rel

package
v0.10.0 Latest Latest
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 Go to latest Published: Jun 2, 2020 License: Apache-2.0 Imports: 21 Imported by: 8

Documentation

Index

Constants

View Source 
const ArrayItemAttr = "@item"
View Source 
const BytesByteAttr = "@byte"

BytesByteAttr is the standard name for the value-attr of a character tuple.

View Source 
const DictValueAttr = "@value"
View Source 
const StringCharAttr = "@char"

StringCharAttr is the standard name for the value-attr of a character tuple.

Variables

View Source 
var (
	None  = Set(GenericSet{frozen.Set{}})
	False = None
	True  = None.With(EmptyTuple)
)

genericSet equivalents for Boolean true and false

View Source 
var DotIdent = IdentExpr{ExprScanner: ExprScanner{Src: *parser.NewScanner(".")}, /* contains filtered or unexported fields */}

DotIdent represents the special identifier '.'.

View Source 
var EmptyNames = Names(frozen.Set{})

EmptyNames is the empty set of names.

View Source 
var LexerNamePat = `([$@A-Za-z_][0-9$@A-Za-z_]*)`

LexerNamePat defines valid unquoted identifiers. This really belongs in rel/syntax/lex.go, but that creates a dep cycle.

Functions

func ASTBranchFromValue 

func ASTBranchFromValue(b Tuple) ast.Branch

func ASTLeafFromValue 

func ASTLeafFromValue(s String) ast.Leaf

func ASTNodeFromValue 

func ASTNodeFromValue(value Value) ast.Node

func AssertEqualValues 

func AssertEqualValues(t *testing.T, expected, actual Value) bool

AssertEqualValues asserts that the two values are Equal.

func AssertExprEvalsToType 

func AssertExprEvalsToType(t *testing.T, expected interface{}, expr Expr) bool

AssertExprEvalsToType asserts that the exprs evaluate to the same value.

func AssertExprPanics 

func AssertExprPanics(t *testing.T, expr Expr) bool

AssertExprPanics asserts that the expr panics when evaluates.

func AssertExprsEvalToSameValue 

func AssertExprsEvalToSameValue(t *testing.T, expected, expr Expr) bool

AssertExprsEvalToSameValue asserts that the exprs evaluate to the same value.

func AttrEnumeratorToMap 

func AttrEnumeratorToMap(e AttrEnumerator) map[string]Value

AttrEnumeratorToMap transcribes its Attrs in a map.

func Combine 

func Combine(a, b Tuple, op CombineOp) map[string]Pair

Combine returns a map of names to pairs of corresponding Values from a and b. Which names appear in the output is determined by the masks provided in op.

func DictTupleMatcher 

func DictTupleMatcher() func(v Value) (key, value Value, matches bool)

func EqualValues 

func EqualValues(expected, actual Value) bool

func GetStringValue 

func GetStringValue(expr Expr) (string, bool)

GetStringValue returns the string value for expr or false if not a string.

func MakeBinValExpr 

func MakeBinValExpr(op string, eval valueEval) func(scanner parser.Scanner, a, b Expr) Expr

MakeBinValExpr returns a function that creates a binExpr for the given logical operator.

func MarshalToJSON 

func MarshalToJSON(value Value) []byte

MarshalToJSON marshals the given value to JSON with sets escaped as s -> {"{||}": s}.

func Repr 

func Repr(v Value) string

func RequireEqualValues 

func RequireEqualValues(t *testing.T, expected, actual Value)

RequireEqualValues requires that the two values are Equal.

func RequireExprsEvalToSameValue 

func RequireExprsEvalToSameValue(t *testing.T, expected, expr Expr)

RequireExprsEvalToSameValue requires that the exprs evaluate to the same value.

func TupleNameRepr 

func TupleNameRepr(name string) string

func TupleOrderedNames 

func TupleOrderedNames(t *GenericTuple) []string

TupleOrderedNames returns the names of this tuple in sorted order.

Types

type AndExpr 

type AndExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

func (AndExpr) Eval 

func (e AndExpr) Eval(local Scope) (Value, error)

func (AndExpr) String 

func (e AndExpr) String() string

type Array 

type Array struct {
	// contains filtered or unexported fields
}

Array is an ordered collection of Values.

func AsArray 

func AsArray(s Set) (Array, bool)

func (Array) ArrayEnumerator 

func (a Array) ArrayEnumerator() (OffsetValueEnumerator, bool)

func (Array) Bind added in v0.3.0 

func (a Array) Bind(scope Scope, value Value) (Scope, error)

Bind it is not supported by now.

func (Array) CallAll added in v0.3.0 

func (a Array) CallAll(arg Value) Set

func (Array) Count 

func (a Array) Count() int

Count returns the number of elements in the Array.

func (Array) Enumerator 

func (a Array) Enumerator() ValueEnumerator

Enumerator returns an enumerator over the Values in the Array.

func (Array) Equal 

func (a Array) Equal(v interface{}) bool

Equal tests two Sets for equality. Any other type returns false.

func (Array) Eval 

func (a Array) Eval(_ Scope) (Value, error)

Eval returns the string.

func (Array) Export 

func (a Array) Export() interface{}

Export exports an Array as a slice.

func (Array) Has 

func (a Array) Has(value Value) bool

Has returns true iff the given Value is in the Array.

func (Array) Hash 

func (a Array) Hash(seed uintptr) uintptr

Hash computes a hash for a Array.

func (Array) IsTrue 

func (a Array) IsTrue() bool

IsTrue returns true if the tuple has attributes.

func (Array) Kind 

func (a Array) Kind() int

Kind returns a number that is unique for each major kind of Value.

func (Array) Less 

func (a Array) Less(v Value) bool

Less returns true iff v is not a number or tuple, or v is a tuple and t precedes v in a lexicographical comparison of their name/value pairs.

func (Array) Map 

func (a Array) Map(f func(v Value) Value) Set

Map maps values per f.

func (Array) Negate 

func (a Array) Negate() Value

Negate returns {@neg: a}.

func (Array) Shift added in v0.5.0 

func (a Array) Shift(offset int) Array

Shift increments the Array's offset

func (Array) Source 

func (a Array) Source() parser.Scanner

Source returns a scanner locating the Array's source code.

func (Array) String 

func (a Array) String() string

String returns a string representation of an Array.

func (Array) Values 

func (a Array) Values() []Value

Values returns the slice of values in the array. Holes in the indices are represented by nil elements.

Callers must not reassign elements of the returned slice.

func (Array) Where 

func (a Array) Where(p func(v Value) bool) Set

Where returns a new Array with all the Values satisfying predicate p.

func (Array) With 

func (a Array) With(value Value) Set

With returns the original Array with given value added. Iff the value was already present, the original Array is returned.

func (Array) Without 

func (a Array) Without(value Value) Set

Without returns the original Array without the given value. Iff the value was already absent, the original Array is returned.

type ArrayExpr 

type ArrayExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

ArrayExpr represents an expr that evaluates to an Array.

func (ArrayExpr) Elements 

func (e ArrayExpr) Elements() []Expr

Elements returns a Set's elements.

func (ArrayExpr) Eval 

func (e ArrayExpr) Eval(local Scope) (Value, error)

Eval returns the subject.

func (ArrayExpr) String 

func (e ArrayExpr) String() string

String returns a string representation of the expression.

type ArrayItemTuple 

type ArrayItemTuple struct {
	// contains filtered or unexported fields
}

ArrayItemTuple represents a tuple of the form (@: at, @item: item).

func NewArrayItemTuple 

func NewArrayItemTuple(at int, item Value) ArrayItemTuple

NewArrayItemTuple constructs a CharTuple.

func (ArrayItemTuple) Attributes 

func (t ArrayItemTuple) Attributes() map[string]Value

Attributes returns attributes as a map.

func (ArrayItemTuple) Count 

func (t ArrayItemTuple) Count() int

Count returns how many attributes are in the Tuple.

func (ArrayItemTuple) Enumerator 

func (t ArrayItemTuple) Enumerator() AttrEnumerator

Enumerator returns an enumerator over the Values in the CharTuple.

func (ArrayItemTuple) Equal 

func (t ArrayItemTuple) Equal(v interface{}) bool

Equal tests two Tuples for equality. Any other type returns false.

func (ArrayItemTuple) Eval 

func (t ArrayItemTuple) Eval(local Scope) (Value, error)

Eval returns the tuple.

func (ArrayItemTuple) Export 

func (t ArrayItemTuple) Export() interface{}

Export exports a Tuple.

func (ArrayItemTuple) Get 

func (t ArrayItemTuple) Get(name string) (Value, bool)

Get returns the Value associated with a name, and true iff it was found.

func (ArrayItemTuple) HasName 

func (t ArrayItemTuple) HasName(name string) bool

HasName returns true iff the Tuple has an attribute with the given name.

func (ArrayItemTuple) Hash 

func (t ArrayItemTuple) Hash(seed uintptr) uintptr

Hash computes a hash for a CharTuple.

func (ArrayItemTuple) IsTrue 

func (t ArrayItemTuple) IsTrue() bool

Bool returns true iff the tuple has attributes.

func (ArrayItemTuple) Kind 

func (t ArrayItemTuple) Kind() int

Kind returns a number that is unique for each major kind of Value.

func (ArrayItemTuple) Less 

func (t ArrayItemTuple) Less(v Value) bool

Less returns true iff v is not a number or tuple, or v is a tuple and t precedes v in a lexicographical comparison of their name/value pairs.

func (ArrayItemTuple) Map 

func (t ArrayItemTuple) Map(f func(Value) Value) Tuple

func (ArrayItemTuple) MustGet 

func (t ArrayItemTuple) MustGet(name string) Value

MustGet returns e.Get(name) or panics if an error occurs.

func (ArrayItemTuple) Names 

func (t ArrayItemTuple) Names() Names

Names returns the attribute names.

func (ArrayItemTuple) Negate 

func (t ArrayItemTuple) Negate() Value

func (ArrayItemTuple) Project 

func (t ArrayItemTuple) Project(names Names) Tuple

Project returns a tuple with the given names from this tuple, or nil if any name wasn't found.

func (ArrayItemTuple) Source 

func (t ArrayItemTuple) Source() parser.Scanner

Source returns a scanner locating the ArrayItemTuple's source code.

func (ArrayItemTuple) String 

func (t ArrayItemTuple) String() string

String returns a string representation of a Tuple.

func (ArrayItemTuple) With 

func (t ArrayItemTuple) With(name string, value Value) Tuple

With returns a Tuple with all name/Value pairs in t (except the one for the given name, if present) with the addition of the given name/Value pair.

func (ArrayItemTuple) Without 

func (t ArrayItemTuple) Without(name string) Tuple

Without returns a Tuple with all name/Value pairs in t exception the one of the given name.

type ArrayItemTupleExpr 

type ArrayItemTupleExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

ArrayItemTupleExpr represents an expr that evaluates to an ArrayItemTuple.

func NewArrayItemTupleExpr 

func NewArrayItemTupleExpr(scanner parser.Scanner, at, value Expr) ArrayItemTupleExpr

NewArrayItemTupleExpr returns a new ArrayItemTupleExpr.

func (ArrayItemTupleExpr) Eval 

func (e ArrayItemTupleExpr) Eval(local Scope) (_ Value, err error)

Eval returns the subject.

func (ArrayItemTupleExpr) String 

func (e ArrayItemTupleExpr) String() string

String returns a string representation of the expression.

type ArrayPattern 

type ArrayPattern struct {
	// contains filtered or unexported fields
}

func NewArrayPattern 

func NewArrayPattern(elements ...Pattern) ArrayPattern

func (ArrayPattern) Bind 

func (p ArrayPattern) Bind(local Scope, value Value) (Scope, error)

func (ArrayPattern) String 

func (p ArrayPattern) String() string

type ArrowExpr 

type ArrowExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

ArrowExpr returns the tuple applied to a function.

func (*ArrowExpr) Eval 

func (e *ArrowExpr) Eval(local Scope) (_ Value, err error)

Eval returns the lhs

func (*ArrowExpr) Fn 

func (e *ArrowExpr) Fn() *Function

Fn returns the function to be applied to the LHS.

func (*ArrowExpr) LHS 

func (e *ArrowExpr) LHS() Expr

LHS returns the LHS of the ArrowExpr.

func (*ArrowExpr) String 

func (e *ArrowExpr) String() string

String returns a string representation of the expression.

type Attr 

type Attr struct {
	Name  string
	Value Value
}

Attr is a name/Value pair used to construct a Tuple.

func AttrEnumeratorToSlice 

func AttrEnumeratorToSlice(e AttrEnumerator) []Attr

AttrEnumeratorToSlice transcribes its Attrs in a slice.

func NewAttr 

func NewAttr(name string, value Value) Attr

NewAttr returns an Attr with the given name and value.

func NewBoolAttr 

func NewBoolAttr(name string, value bool) Attr

NewBoolAttr return an attr with a bool value.

func NewFloatAttr 

func NewFloatAttr(name string, value float64) Attr

NewFloatAttr return an attr with a float value.

func NewIntAttr 

func NewIntAttr(name string, value int) Attr

NewIntAttr return an attr with an int value.

func NewNativeFunctionAttr 

func NewNativeFunctionAttr(name string, fn func(Value) Value) Attr

NewNativeFunction returns a new function.

func NewStringAttr 

func NewStringAttr(name string, value []rune) Attr

NewStringAttr return an attr with a string value.

func NewTupleAttr 

func NewTupleAttr(name string, attrs ...Attr) Attr

NewTupleAttr return an attr with a new tuple value.

type AttrEnumerator 

type AttrEnumerator interface {
	MoveNext() bool
	Current() (string, Value)
}

AttrEnumerator enumerates Values.

type AttrExpr 

type AttrExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

AttrExpr represents a single name:expr in a TupleExpr.

func MustNewAttrExpr 

func MustNewAttrExpr(scanner parser.Scanner, name string, expr Expr) AttrExpr

func NewAttrExpr 

func NewAttrExpr(scanner parser.Scanner, name string, expr Expr) (AttrExpr, error)

NewAttrExpr constructs a new AttrExpr from the given arguments.

func NewWildcardExpr 

func NewWildcardExpr(scanner parser.Scanner, lhs Expr) AttrExpr

NewWildcardExpr constructs a new wildcard AttrExpr.

func (*AttrExpr) Apply 

func (e *AttrExpr) Apply(
	local Scope, tuple Tuple,
) (Tuple, error)

Apply applies the AttrExpr to the Tuple.

func (*AttrExpr) Expr 

func (e *AttrExpr) Expr() Expr

Expr returns the AttrExpr's expr.

func (*AttrExpr) IsWildcard 

func (e *AttrExpr) IsWildcard() bool

IsWildcard returns true iff the AttrExpr is a wildcard expression.

func (*AttrExpr) Name 

func (e *AttrExpr) Name() string

Name returns the AttrExpr's name.

type BinExpr 

type BinExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

BinExpr represents a range of operators.

func (*BinExpr) Eval 

func (e *BinExpr) Eval(local Scope) (_ Value, err error)

Eval returns the subject

func (*BinExpr) LHS 

func (e *BinExpr) LHS() Expr

LHS returns the left hand side of the BinExpr.

func (*BinExpr) RHS 

func (e *BinExpr) RHS() Expr

RHS returns the right hand side of the BinExpr.

func (*BinExpr) String 

func (e *BinExpr) String() string

String returns a string representation of the expression.

type BindMatcher 

type BindMatcher struct {
	// contains filtered or unexported fields
}

func Bind 

func Bind(target interface{}) BindMatcher

func (BindMatcher) Match 

func (m BindMatcher) Match(v Value) bool

type Bytes 

type Bytes struct {
	// contains filtered or unexported fields
}

Bytes is a set of Values.

func AsBytes 

func AsBytes(s Set) (Bytes, bool)

func (Bytes) ArrayEnumerator 

func (b Bytes) ArrayEnumerator() (OffsetValueEnumerator, bool)

func (Bytes) Bytes 

func (b Bytes) Bytes() []byte

Bytes returns the bytes of b. The caller must not modify the contents.

func (Bytes) CallAll added in v0.3.0 

func (b Bytes) CallAll(arg Value) Set

func (Bytes) Count 

func (b Bytes) Count() int

Count returns the number of elements in the Bytes.

func (Bytes) Enumerator 

func (b Bytes) Enumerator() ValueEnumerator

Enumerator returns an enumerator over the Values in the Bytes.

func (Bytes) Equal 

func (b Bytes) Equal(v interface{}) bool

Equal tests two Sets for equality. Any other type returns false.

func (Bytes) Eval 

func (b Bytes) Eval(_ Scope) (Value, error)

Eval returns the string.

func (Bytes) Export 

func (b Bytes) Export() interface{}

Export exports a Bytes as a string.

func (Bytes) Has 

func (b Bytes) Has(value Value) bool

Has returns true iff the given Value is in the Bytes.

func (Bytes) Hash 

func (b Bytes) Hash(seed uintptr) uintptr

Hash computes a hash for a Bytes.

func (Bytes) IsTrue 

func (b Bytes) IsTrue() bool

Bool returns true iff the tuple has attributes.

func (Bytes) Kind 

func (b Bytes) Kind() int

Kind returns a number that is unique for each major kind of Value.

func (Bytes) Less 

func (b Bytes) Less(v Value) bool

Less returns true iff v is not a number or tuple, or v is a tuple and t precedes v in a lexicographical comparison of their name/value pairs.

func (Bytes) Map 

func (b Bytes) Map(f func(v Value) Value) Set

Map maps values per f.

func (Bytes) Negate 

func (b Bytes) Negate() Value

Negate returns {(negateTag): b}.

func (Bytes) Source 

func (b Bytes) Source() parser.Scanner

Source returns a scanner locating the Bytes's source code.

func (Bytes) String 

func (b Bytes) String() string

String returns a string representation of a Bytes.

func (Bytes) Where 

func (b Bytes) Where(p func(v Value) bool) Set

Where returns a new Bytes with all the Values satisfying predicate p.

func (Bytes) With 

func (b Bytes) With(value Value) Set

With returns the original Bytes with given value added. Iff the value was already present, the original Bytes is returned.

func (Bytes) Without 

func (b Bytes) Without(value Value) Set

Without returns the original Bytes without the given value. Iff the value was already absent, the original Bytes is returned.

type BytesByteTuple 

type BytesByteTuple struct {
	// contains filtered or unexported fields
}

BytesByteTuple represents a tuple of the form (@: at, @byte: byteval).

func NewBytesByteTuple 

func NewBytesByteTuple(at int, byteval byte) BytesByteTuple

NewBytesByteTuple constructs a BytesByteTuple.

func (BytesByteTuple) Attributes 

func (t BytesByteTuple) Attributes() map[string]Value

Attributes returns attributes as a map.

func (BytesByteTuple) Count 

func (t BytesByteTuple) Count() int

Count returns how many attributes are in the Tuple.

func (BytesByteTuple) Enumerator 

func (t BytesByteTuple) Enumerator() AttrEnumerator

Enumerator returns an enumerator over the Values in the BytesByteTuple.

func (BytesByteTuple) Equal 

func (t BytesByteTuple) Equal(v interface{}) bool

Equal tests two Tuples for equality. Any other type returns false.

func (BytesByteTuple) Eval 

func (t BytesByteTuple) Eval(local Scope) (Value, error)

Eval returns the tuple.

func (BytesByteTuple) Export 

func (t BytesByteTuple) Export() interface{}

Export exports a Tuple.

func (BytesByteTuple) Get 

func (t BytesByteTuple) Get(name string) (Value, bool)

Get returns the Value associated with a name, and true iff it was found.

func (BytesByteTuple) HasName 

func (t BytesByteTuple) HasName(name string) bool

HasName returns true iff the Tuple has an attribute with the given name.

func (BytesByteTuple) Hash 

func (t BytesByteTuple) Hash(seed uintptr) uintptr

Hash computes a hash for a BytesByteTuple.

func (BytesByteTuple) IsTrue 

func (t BytesByteTuple) IsTrue() bool

Bool returns true iff the tuple has attributes.

func (BytesByteTuple) Kind 

func (t BytesByteTuple) Kind() int

Kind returns a number that is unique for each major kind of Value.

func (BytesByteTuple) Less 

func (t BytesByteTuple) Less(v Value) bool

Less returns true iff v is not a number or tuple, or v is a tuple and t precedes v in a lexicographical comparison of their name/value pairs.

func (BytesByteTuple) Map 

func (t BytesByteTuple) Map(f func(Value) Value) Tuple

func (BytesByteTuple) MustGet 

func (t BytesByteTuple) MustGet(name string) Value

MustGet returns e.Get(name) or panics if an error occurs.

func (BytesByteTuple) Names 

func (t BytesByteTuple) Names() Names

Names returns the attribute names.

func (BytesByteTuple) Negate 

func (t BytesByteTuple) Negate() Value

func (BytesByteTuple) Project 

func (t BytesByteTuple) Project(names Names) Tuple

Project returns a tuple with the given names from this tuple, or nil if any name wasn't found.

func (BytesByteTuple) Source 

func (t BytesByteTuple) Source() parser.Scanner

Source returns a scanner locating the BytesByteTuple's source code.

func (BytesByteTuple) String 

func (t BytesByteTuple) String() string

String returns a string representation of a Tuple.

func (BytesByteTuple) With 

func (t BytesByteTuple) With(name string, value Value) Tuple

With returns a Tuple with all name/Value pairs in t (except the one for the given name, if present) with the addition of the given name/Value pair.

func (BytesByteTuple) Without 

func (t BytesByteTuple) Without(name string) Tuple

Without returns a Tuple with all name/Value pairs in t exception the one of the given name.

type BytesEnumerator 

type BytesEnumerator struct {
	// contains filtered or unexported fields
}

BytesEnumerator represents an enumerator over a Bytes.

func (*BytesEnumerator) Current 

func (e *BytesEnumerator) Current() Value

Current returns the enumerator'b current Value.

func (*BytesEnumerator) MoveNext 

func (e *BytesEnumerator) MoveNext() bool

MoveNext moves the enumerator to the next Value.

type BytesExpr added in v0.3.0 

type BytesExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

BytesExpr is an expression that evaluates to a Byte Array

func (BytesExpr) Eval added in v0.3.0 

func (b BytesExpr) Eval(local Scope) (Value, error)

func (BytesExpr) String added in v0.3.0 

func (b BytesExpr) String() string

type Closure 

type Closure struct {
	// contains filtered or unexported fields
}

Closure represents the closure of a function over a scope.

func (Closure) ArrayEnumerator added in v0.3.0 

func (c Closure) ArrayEnumerator() (OffsetValueEnumerator, bool)

func (Closure) CallAll added in v0.3.0 

func (c Closure) CallAll(arg Value) Set

func (Closure) Count added in v0.3.0 

func (c Closure) Count() int

func (Closure) Enumerator added in v0.3.0 

func (c Closure) Enumerator() ValueEnumerator

func (Closure) Equal 

func (c Closure) Equal(i interface{}) bool

Equal tests two Values for equality. Any other type returns false.

func (Closure) EqualClosure 

func (c Closure) EqualClosure(d Closure) bool

Equal tests two Values for equality. Any other type returns false.

func (Closure) Eval 

func (c Closure) Eval(local Scope) (Value, error)

Eval returns the Value

func (Closure) Export 

func (c Closure) Export() interface{}

Export exports a Closure.

func (Closure) Has added in v0.3.0 

func (c Closure) Has(v Value) bool

func (Closure) Hash 

func (c Closure) Hash(seed uintptr) uintptr

Hash computes a hash for a Closure.

func (Closure) IsTrue 

func (c Closure) IsTrue() bool

Bool returns true iff the tuple has attributes.

func (Closure) Kind 

func (c Closure) Kind() int

Kind returns a number that is unique for each major kind of Value.

func (Closure) Less 

func (c Closure) Less(d Value) bool

Less returns true iff g is not a number or f.number < g.number.

func (Closure) Map added in v0.3.0 

func (c Closure) Map(f func(Value) Value) Set

func (Closure) Negate 

func (c Closure) Negate() Value

Negate returns {(negateTag): f}.

func (Closure) Source 

func (c Closure) Source() parser.Scanner

Source returns a scanner locating the Closure's source code.

func (Closure) String 

func (c Closure) String() string

String returns a string representation of the expression.

func (Closure) Where added in v0.3.0 

func (c Closure) Where(f func(Value) bool) Set

func (Closure) With added in v0.3.0 

func (c Closure) With(v Value) Set

func (Closure) Without added in v0.3.0 

func (c Closure) Without(v Value) Set

type CombineOp 

type CombineOp int

CombineOp specifies which pairings to include in Combine(). 

const (
	OnlyOnLHS CombineOp = 1 << iota // Include elements only found on lhs.
	InBoth                          // Include elements found on both sides.
	OnlyOnRHS                       // Include elements only found on rhs.

	AllPairs = OnlyOnLHS | InBoth | OnlyOnRHS
)

The following masks control which elements to include in Combine().

type CompareExpr 

type CompareExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

CompareExpr represents a range of operators.

func NewCompareExpr 

func NewCompareExpr(scanner parser.Scanner, args []Expr, comps []CompareFunc, ops []string) CompareExpr

func (CompareExpr) Eval 

func (e CompareExpr) Eval(local Scope) (Value, error)

Eval returns the subject

func (CompareExpr) String 

func (e CompareExpr) String() string

String returns a string representation of the expression.

type CompareFunc 

type CompareFunc func(a, b Value) bool

type CondControlVarExpr 

type CondControlVarExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

CondControlVarExpr returns the tuple applied to a function, the expression looks like: let a = 1 + 1; a cond (1 : 2 + 1, 2 : 5, *: 10) let a = 1 + 1; let b = a cond (1 : 2 + 1, 2 : 5, *: 10); b

func (CondControlVarExpr) Eval 

func (e CondControlVarExpr) Eval(local Scope) (Value, error)

Eval returns the value of valid condition and whose value equals to the control var value, or the value of default condition.

func (CondControlVarExpr) String 

func (e CondControlVarExpr) String() string

String returns a string representation of the expression.

type CondExpr 

type CondExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

CondExpr returns the tuple applied to a function, the expression looks like: cond (1 > 0: 2 + 1, 3 > 4: 5, _: 10). The original keyword was switch (SwitchExpr), and finally it was chanaged from switch to cond. The keyword cond is more unusual, therefore less likely to be chosen as a regular name, and avoids accidental comparisons with the switch statement in other languages.

func (CondExpr) Eval 

func (e CondExpr) Eval(local Scope) (Value, error)

Eval returns the value of true condition, or default condition value.

func (CondExpr) String 

func (e CondExpr) String() string

String returns a string representation of the expression.

type CondPatternControlVarExpr added in v0.3.0 

type CondPatternControlVarExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

CondPatternControlVarExpr which is used for `cond` pattern matching.

func (CondPatternControlVarExpr) Eval added in v0.3.0 

func (expr CondPatternControlVarExpr) Eval(local Scope) (Value, error)

Eval evaluates to find the first valid condition and return its value.

func (CondPatternControlVarExpr) String added in v0.3.0 

func (expr CondPatternControlVarExpr) String() string

type ContextErr added in v0.4.0 

type ContextErr struct {
	// contains filtered or unexported fields
}

func (ContextErr) Error added in v0.4.0 

func (c ContextErr) Error() string

func (ContextErr) GetLastScope added in v0.4.0 

func (c ContextErr) GetLastScope() Scope

GetLastScope gets the scope nearest to the error

func (ContextErr) NextErr added in v0.8.0 

func (c ContextErr) NextErr() error

NextErr returns the error contained in ContextErr

type DArrowExpr 

type DArrowExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

DArrowExpr returns the set applied elementwise to a function.

func (*DArrowExpr) Eval 

func (e *DArrowExpr) Eval(local Scope) (_ Value, err error)

Eval returns the lhs transformed elementwise by fn.

func (*DArrowExpr) Fn 

func (e *DArrowExpr) Fn() *Function

Fn returns the function to be applied to the LHS.

func (*DArrowExpr) LHS 

func (e *DArrowExpr) LHS() Expr

LHS returns the LHS of the DArrowExpr.

func (*DArrowExpr) String 

func (e *DArrowExpr) String() string

String returns a string representation of the expression.

type Dict 

type Dict struct {
	// contains filtered or unexported fields
}

Dict is a map from keys to values.

func (Dict) ArrayEnumerator 

func (d Dict) ArrayEnumerator() (OffsetValueEnumerator, bool)

func (Dict) CallAll added in v0.3.0 

func (d Dict) CallAll(arg Value) Set

func (Dict) Count 

func (d Dict) Count() int

func (Dict) DictEnumerator 

func (d Dict) DictEnumerator() *DictEnumerator

func (Dict) Enumerator 

func (d Dict) Enumerator() ValueEnumerator

func (Dict) Equal 

func (d Dict) Equal(v interface{}) bool

func (Dict) Eval 

func (d Dict) Eval(local Scope) (Value, error)

func (Dict) Export 

func (d Dict) Export() interface{}

func (Dict) Has 

func (d Dict) Has(v Value) bool

func (Dict) Hash 

func (d Dict) Hash(seed uintptr) uintptr

func (Dict) IsTrue 

func (d Dict) IsTrue() bool

func (Dict) Kind 

func (d Dict) Kind() int

Kind returns a number that is unique for each major kind of Value.

func (Dict) Less 

func (d Dict) Less(v Value) bool

func (Dict) Map 

func (d Dict) Map(m func(Value) Value) Set

func (Dict) Negate 

func (d Dict) Negate() Value

func (Dict) OrderedEntries 

func (d Dict) OrderedEntries() []DictEntryTuple

func (Dict) Source 

func (d Dict) Source() parser.Scanner

Source returns a scanner locating the Dict's source code.

func (Dict) String 

func (d Dict) String() string

func (Dict) Where 

func (d Dict) Where(pred func(Value) bool) Set

func (Dict) With 

func (d Dict) With(v Value) Set

func (Dict) Without 

func (d Dict) Without(v Value) Set

type DictEntryTuple 

type DictEntryTuple struct {
	// contains filtered or unexported fields
}

DictEntryTuple represents a tuple of the form (@: at, @value: item).

func NewDictEntryTuple 

func NewDictEntryTuple(at Value, item Value) DictEntryTuple

NewDictEntryTuple constructs a CharTuple.

func (DictEntryTuple) Attributes 

func (t DictEntryTuple) Attributes() map[string]Value

Attributes returns attributes as a map.

func (DictEntryTuple) Count 

func (t DictEntryTuple) Count() int

Count returns how many attributes are in the Tuple.

func (DictEntryTuple) Enumerator 

func (t DictEntryTuple) Enumerator() AttrEnumerator

Enumerator returns an enumerator over the Values in the CharTuple.

func (DictEntryTuple) Equal 

func (t DictEntryTuple) Equal(v interface{}) bool

Equal tests two Tuples for equality. Any other type returns false.

func (DictEntryTuple) Eval 

func (t DictEntryTuple) Eval(local Scope) (Value, error)

Eval returns the tuple.

func (DictEntryTuple) Export 

func (t DictEntryTuple) Export() interface{}

Export exports a Tuple.

func (DictEntryTuple) Get 

func (t DictEntryTuple) Get(name string) (Value, bool)

Get returns the Value associated with a name, and true iff it was found.

func (DictEntryTuple) HasName 

func (t DictEntryTuple) HasName(name string) bool

HasName returns true iff the Tuple has an attribute with the given name.

func (DictEntryTuple) Hash 

func (t DictEntryTuple) Hash(seed uintptr) uintptr

Hash computes a hash for a CharTuple.

func (DictEntryTuple) IsTrue 

func (t DictEntryTuple) IsTrue() bool

Bool returns true iff the tuple has attributes.

func (DictEntryTuple) Kind 

func (t DictEntryTuple) Kind() int

Kind returns a number that is unique for each major kind of Value.

func (DictEntryTuple) Less 

func (t DictEntryTuple) Less(v Value) bool

Less returns true iff v is not a number or tuple, or v is a tuple and t precedes v in a lexicographical comparison of their name/value pairs.

func (DictEntryTuple) Map 

func (t DictEntryTuple) Map(f func(Value) Value) Tuple

func (DictEntryTuple) MustGet 

func (t DictEntryTuple) MustGet(name string) Value

MustGet returns e.Get(name) or panics if an error occurs.

func (DictEntryTuple) Names 

func (t DictEntryTuple) Names() Names

Names returns the attribute names.

func (DictEntryTuple) Negate 

func (t DictEntryTuple) Negate() Value

func (DictEntryTuple) Project 

func (t DictEntryTuple) Project(names Names) Tuple

Project returns a tuple with the given names from this tuple, or nil if any name wasn't found.

func (DictEntryTuple) Source 

func (t DictEntryTuple) Source() parser.Scanner

Source returns a scanner locating the DictEntryTuple's source code.

func (DictEntryTuple) String 

func (t DictEntryTuple) String() string

String returns a string representation of a Tuple.

func (DictEntryTuple) With 

func (t DictEntryTuple) With(name string, value Value) Tuple

With returns a Tuple with all name/Value pairs in t (except the one for the given name, if present) with the addition of the given name/Value pair.

func (DictEntryTuple) Without 

func (t DictEntryTuple) Without(name string) Tuple

Without returns a Tuple with all name/Value pairs in t exception the one of the given name.

type DictEntryTupleExpr 

type DictEntryTupleExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

DictEntryTupleExpr represents an expr that evaluates to a DictEntryTuple.

func NewDictEntryTupleExpr 

func NewDictEntryTupleExpr(scanner parser.Scanner, at, value Expr) DictEntryTupleExpr

NewDictEntryTupleExpr returns a new dictEntryTupleExpr.

func (DictEntryTupleExpr) Eval 

func (e DictEntryTupleExpr) Eval(local Scope) (Value, error)

Eval returns the subject

func (DictEntryTupleExpr) String 

func (e DictEntryTupleExpr) String() string

String returns a string representation of the expression.

type DictEnumerator 

type DictEnumerator struct {
	// contains filtered or unexported fields
}

func (*DictEnumerator) Current 

func (a *DictEnumerator) Current() (key, value Value)

func (*DictEnumerator) MoveNext 

func (a *DictEnumerator) MoveNext() bool

type DictExpr 

type DictExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

DictExpr represents an expression that yields a dict.

func (DictExpr) Eval 

func (e DictExpr) Eval(local Scope) (Value, error)

Eval returns the subject

func (DictExpr) String 

func (e DictExpr) String() string

String returns a string representation of the expression.

type DictPattern added in v0.3.0 

type DictPattern struct {
	// contains filtered or unexported fields
}

func NewDictPattern added in v0.3.0 

func NewDictPattern(entries ...DictPatternEntry) DictPattern

func (DictPattern) Bind added in v0.3.0 

func (p DictPattern) Bind(local Scope, value Value) (Scope, error)

func (DictPattern) String added in v0.3.0 

func (p DictPattern) String() string

type DictPatternEntry added in v0.3.0 

type DictPatternEntry struct {
	// contains filtered or unexported fields
}

func NewDictPatternEntry added in v0.3.0 

func NewDictPatternEntry(at Expr, value Pattern) DictPatternEntry

func (DictPatternEntry) String added in v0.3.0 

func (p DictPatternEntry) String() string

type DotExpr 

type DotExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

DotExpr returns the tuple or set with a single field replaced by an expression.

func (*DotExpr) Attr 

func (x *DotExpr) Attr() string

Attr returns the name of the attribute accessed by the DotExpr.

func (*DotExpr) Eval 

func (x *DotExpr) Eval(local Scope) (_ Value, err error)

Eval returns the lhs

func (*DotExpr) String 

func (x *DotExpr) String() string

String returns a string representation of the expression.

func (*DotExpr) Subject 

func (x *DotExpr) Subject() Expr

Subject returns the DotExpr's LHS.

type Expr 

type Expr interface {
	// Require a String() method.
	fmt.Stringer

	// Eval evaluates the expr in a given scope.
	Eval(local Scope) (Value, error)

	Source() parser.Scanner
}

Expr represents an arr.ai expression.

func NewAddExpr 

func NewAddExpr(scanner parser.Scanner, a, b Expr) Expr

NewAddExpr evaluates a + b, given two Numbers.

func NewAndExpr 

func NewAndExpr(scanner parser.Scanner, a, b Expr) Expr

func NewArrayExpr 

func NewArrayExpr(scanner parser.Scanner, elements ...Expr) Expr

NewArrayExpr returns a new Expr that constructs an Array.

func NewArrowExpr 

func NewArrowExpr(scanner parser.Scanner, lhs, fn Expr) Expr

NewArrowExpr returns a new ArrowExpr.

func NewBytesExpr added in v0.3.0 

func NewBytesExpr(scanner parser.Scanner, elements ...Expr) Expr

func NewCallExpr 

func NewCallExpr(scanner parser.Scanner, a, b Expr) Expr

NewCallExpr evaluates a without b, given a set lhs.

func NewCallExprCurry 

func NewCallExprCurry(scanner parser.Scanner, f Expr, args ...Expr) Expr

func NewConcatExpr 

func NewConcatExpr(scanner parser.Scanner, a, b Expr) Expr

NewConcatExpr evaluates a ++ b.

func NewCondControlVarExpr 

func NewCondControlVarExpr(scanner parser.Scanner, controlVar Expr, dictExpr Expr) Expr

NewCondControlVarExpr returns a new CondControlVarExpr.

func NewCondExpr 

func NewCondExpr(scanner parser.Scanner, dict Expr) Expr

NewCondExpr returns a new CondExpr.

func NewCondPatternControlVarExpr added in v0.3.0 

func NewCondPatternControlVarExpr(scanner parser.Scanner, controlVar Expr, patternExprs ...PatternExpr) Expr

NewCondPatternControlVarExpr returns a new CondPatternControlVarExpr.

func NewCountExpr 

func NewCountExpr(scanner parser.Scanner, a Expr) Expr

NewCountExpr evaluates to the number of elements in a.

func NewDictExpr 

func NewDictExpr(scanner parser.Scanner,
	allowDupKeys bool, dictExprAlways bool, entryExprs ...DictEntryTupleExpr) Expr

NewDictExpr returns a new DictExpr from pairs.

func NewDiffExpr 

func NewDiffExpr(scanner parser.Scanner, a, b Expr) Expr

NewDiffExpr evaluates a &~ b.

func NewDivExpr 

func NewDivExpr(scanner parser.Scanner, a, b Expr) Expr

NewDivExpr evaluates a / b, given two Numbers.

func NewDotExpr 

func NewDotExpr(scanner parser.Scanner, lhs Expr, attr string) Expr

NewDotExpr returns a new DotExpr that fetches the given attr from the lhs, which is expected to be a tuple.

func NewEvalExpr 

func NewEvalExpr(scanner parser.Scanner, a Expr) Expr

NewEvalExpr evaluates to *a, given a set lhs.

func NewFunction 

func NewFunction(scanner parser.Scanner, arg Pattern, body Expr) Expr

NewFunction returns a new function.

func NewIdivExpr 

func NewIdivExpr(scanner parser.Scanner, a, b Expr) Expr

NewIdivExpr evaluates ⎣a / b⎦, given two Numbers.

func NewIfElseExpr 

func NewIfElseExpr(scanner parser.Scanner, ifTrue, cond, ifFalse Expr) Expr

NewIfElseExpr returns a new IfElseExpr. Deprecated: NewIfElseExpr will be removed, it should use NewCondExpr instead.

func NewIndexedSequenceMapExpr 

func NewIndexedSequenceMapExpr(scanner parser.Scanner, lhs, rhs Expr) Expr

func NewIntersectExpr 

func NewIntersectExpr(scanner parser.Scanner, a, b Expr) Expr

NewIntersectExpr evaluates a <&> b.

func NewJoinExpr 

func NewJoinExpr(scanner parser.Scanner, a, b Expr) Expr

NewJoinExpr evaluates a <&> b.

func NewMapExpr 

func NewMapExpr(scanner parser.Scanner, lhs Expr, fn Expr) Expr

NewDArrowExpr returns a new DArrowExpr.

func NewMaxExpr 

func NewMaxExpr(scanner parser.Scanner, a, b Expr) Expr

NewMaxExpr evaluates to the max of expr over all elements in a.

func NewMeanExpr 

func NewMeanExpr(scanner parser.Scanner, a, b Expr) Expr

NewMeanExpr evaluates to the mean of expr over all elements in a.

func NewMedianExpr 

func NewMedianExpr(scanner parser.Scanner, a, b Expr) Expr

NewMedianExpr evaluates to the median of expr over all elements in a.

func NewMinExpr 

func NewMinExpr(scanner parser.Scanner, a, b Expr) Expr

NewMinExpr evaluates to the min of expr over all elements in a.

func NewModExpr 

func NewModExpr(scanner parser.Scanner, a, b Expr) Expr

NewModExpr evaluates a % b, given two Numbers.

func NewMulExpr 

func NewMulExpr(scanner parser.Scanner, a, b Expr) Expr

NewMulExpr evaluates a * b, given two Numbers.

func NewNegExpr 

func NewNegExpr(scanner parser.Scanner, a Expr) Expr

NewNegExpr evaluates to -a.

func NewNestExpr 

func NewNestExpr(scanner parser.Scanner, lhs Expr, attrs Names, attr string) Expr

NewNestExpr returns a new NestExpr.

func NewNotExpr 

func NewNotExpr(scanner parser.Scanner, a Expr) Expr

NewNotExpr evaluates to !a.

func NewOffsetExpr 

func NewOffsetExpr(scanner parser.Scanner, n, s Expr) Expr

NewOffsetExpr returns a new OffsetExpr

func NewOrExpr 

func NewOrExpr(scanner parser.Scanner, a, b Expr) Expr

func NewOrderByExpr 

func NewOrderByExpr(scanner parser.Scanner, a, key Expr) Expr

NewOrderByExpr evaluates a orderby key, given a set lhs, returning an array.

func NewOrderExpr 

func NewOrderExpr(scanner parser.Scanner, a, key Expr) Expr

NewOrderExpr evaluates a order less, given a set lhs, returning an array.

func NewPosExpr 

func NewPosExpr(scanner parser.Scanner, a Expr) Expr

NewPosExpr evaluates to a.

func NewPowExpr 

func NewPowExpr(scanner parser.Scanner, a, b Expr) Expr

NewPowExpr evaluates a to the power of b, given two Numbers.

func NewPowerSetExpr 

func NewPowerSetExpr(scanner parser.Scanner, a Expr) Expr

NewPowerSetExpr evaluates to ^a.

func NewRankExpr added in v0.3.0 

func NewRankExpr(scanner parser.Scanner, a, key Expr) Expr

NewRankExpr evaluates a rank tuplef, given a relation lhs, returning a new relation with each lhs tuple augmented by the tuplef attrs containing the corresponding rank.

func NewRecursionExpr added in v0.3.0 

func NewRecursionExpr(scanner parser.Scanner, name Pattern, fn Expr, fix, fixt Value) Expr

func NewReduceExpr 

func NewReduceExpr(scanner parser.Scanner,
	a Expr,
	f *Function,
	format string,
	init func(s Set) (interface{}, error),
	reduce func(acc interface{}, v Value) (interface{}, error),
	output func(acc interface{}) (Value, error),
) Expr

NewReduceExpr evaluates a reduce f, given a set lhs.

func NewRelationExpr 

func NewRelationExpr(scanner parser.Scanner, names []string, tuples ...[]Expr) (Expr, error)

NewRelationExpr returns a new relation for the given data.

func NewSafeTailExpr added in v0.3.0 

func NewSafeTailExpr(scanner parser.Scanner, fallback, base Expr, tailExprs []SafeTailCallback) Expr

func NewSequenceMapExpr 

func NewSequenceMapExpr(scanner parser.Scanner, lhs Expr, fn Expr) Expr

NewAngleArrowExpr returns a new AtArrowExpr.

func NewSetExpr 

func NewSetExpr(scanner parser.Scanner, elements ...Expr) Expr

NewSetExpr returns a new TupleExpr.

func NewSingleExpr added in v0.3.0 

func NewSingleExpr(scanner parser.Scanner, a Expr) Expr

NewSingleExpr evaluates to the single element in a or fails if a count != 1.

func NewSubExpr 

func NewSubExpr(scanner parser.Scanner, a, b Expr) Expr

NewSubExpr evaluates a - b, given two Numbers.

func NewSubModExpr 

func NewSubModExpr(scanner parser.Scanner, a, b Expr) Expr

NewSubModExpr evaluates a % b, given two Numbers.

func NewSumExpr 

func NewSumExpr(scanner parser.Scanner, a, b Expr) Expr

NewSumExpr evaluates to the sum of expr over all elements in a.

func NewSymmDiffExpr 

func NewSymmDiffExpr(scanner parser.Scanner, a, b Expr) Expr

NewSymmDiffExpr evaluates a ~~ b.

func NewTupleExpr 

func NewTupleExpr(scanner parser.Scanner, attrs ...AttrExpr) Expr

NewTupleExpr returns a new TupleExpr.

func NewTupleExprFromMap 

func NewTupleExprFromMap(scanner parser.Scanner, attrMap map[string]Expr) Expr

NewTupleExprFromMap returns a new TupleExpr from a map[string]Expr.

func NewTupleMapExpr 

func NewTupleMapExpr(scanner parser.Scanner, lhs Expr, fn Expr) Expr

NewAngleArrowExpr returns a new AtArrowExpr.

func NewUnionExpr 

func NewUnionExpr(scanner parser.Scanner, a, b Expr) Expr

NewUnionExpr evaluates a | b.

func NewUnnestExpr 

func NewUnnestExpr(scanner parser.Scanner, lhs Expr, attr string) Expr

NewUnnestExpr returns a new UnnestExpr.

func NewWhereExpr 

func NewWhereExpr(scanner parser.Scanner, a, pred Expr) Expr

NewWhereExpr evaluates a where pred, given a set lhs.

func NewWithExpr 

func NewWithExpr(scanner parser.Scanner, a, b Expr) Expr

NewWithExpr evaluates a with b, given a set lhs.

func NewWithoutExpr 

func NewWithoutExpr(scanner parser.Scanner, a, b Expr) Expr

NewWithoutExpr evaluates a without b, given a set lhs.

type ExprClosure 

type ExprClosure struct {
	// contains filtered or unexported fields
}

ExprClosure represents the closure of an expression over a scope.

func (ExprClosure) ArrayEnumerator added in v0.3.0 

func (ExprClosure) ArrayEnumerator() (OffsetValueEnumerator, bool)

func (ExprClosure) CallAll added in v0.3.0 

func (c ExprClosure) CallAll(arg Value) Set

func (ExprClosure) Count added in v0.3.0 

func (ExprClosure) Count() int

func (ExprClosure) Enumerator added in v0.3.0 

func (ExprClosure) Enumerator() ValueEnumerator

func (ExprClosure) Equal 

func (c ExprClosure) Equal(i interface{}) bool

Equal tests two Values for equality. Any other type returns false.

func (ExprClosure) EqualExprClosure 

func (c ExprClosure) EqualExprClosure(d ExprClosure) bool

Equal tests two Values for equality. Any other type returns false.

func (ExprClosure) Eval 

func (c ExprClosure) Eval(_ Scope) (Value, error)

Eval returns the Value

func (ExprClosure) Export 

func (c ExprClosure) Export() interface{}

Export exports a ExprClosure.

func (ExprClosure) Has added in v0.3.0 

func (ExprClosure) Has(Value) bool

func (ExprClosure) Hash 

func (c ExprClosure) Hash(seed uintptr) uintptr

Hash computes a hash for a ExprClosure.

func (ExprClosure) IsTrue 

func (c ExprClosure) IsTrue() bool

Bool returns true iff the tuple has attributes.

func (ExprClosure) Kind 

func (c ExprClosure) Kind() int

Kind returns a number that is unique for each major kind of Value.

func (ExprClosure) Less 

func (c ExprClosure) Less(d Value) bool

Less returns true iff g is not a number or f.number < g.number.

func (ExprClosure) Map added in v0.3.0 

func (ExprClosure) Map(func(Value) Value) Set

func (ExprClosure) Negate 

func (c ExprClosure) Negate() Value

Negate returns {(negateTag): f}.

func (ExprClosure) Source 

func (c ExprClosure) Source() parser.Scanner

Source returns a scanner locating the ExprClosure's source code.

func (ExprClosure) String 

func (c ExprClosure) String() string

String returns a string representation of the expression.

func (ExprClosure) Where added in v0.3.0 

func (ExprClosure) Where(func(Value) bool) Set

func (ExprClosure) With added in v0.3.0 

func (c ExprClosure) With(Value) Set

func (ExprClosure) Without added in v0.3.0 

func (ExprClosure) Without(Value) Set

type ExprScanner 

type ExprScanner struct {
	Src parser.Scanner
}

func (ExprScanner) Source 

func (e ExprScanner) Source() parser.Scanner

Source returns a scanner locating the expression's source code.

type ExprsPattern added in v0.3.0 

type ExprsPattern struct {
	// contains filtered or unexported fields
}

func NewExprsPattern added in v0.3.0 

func NewExprsPattern(exprs ...Expr) ExprsPattern

func (ExprsPattern) Bind added in v0.3.0 

func (ep ExprsPattern) Bind(scope Scope, value Value) (Scope, error)

func (ExprsPattern) String added in v0.3.0 

func (ep ExprsPattern) String() string

type ExtraElementPattern added in v0.3.0 

type ExtraElementPattern struct {
	// contains filtered or unexported fields
}

func NewExtraElementPattern added in v0.3.0 

func NewExtraElementPattern(ident string) ExtraElementPattern

func (ExtraElementPattern) Bind added in v0.3.0 

func (p ExtraElementPattern) Bind(scope Scope, value Value) (Scope, error)

func (ExtraElementPattern) String added in v0.3.0 

func (p ExtraElementPattern) String() string

type FuncMatcher 

type FuncMatcher struct {
	// contains filtered or unexported fields
}

func MatchFunc 

func MatchFunc(tuples [][2]Matcher, rest Matcher) FuncMatcher

func (FuncMatcher) Match 

func (m FuncMatcher) Match(v Value) bool

type Function 

type Function struct {
	ExprScanner
	// contains filtered or unexported fields
}

Function represents a binary relation uniquely mapping inputs to outputs.

func ExprAsFunction 

func ExprAsFunction(expr Expr) *Function

ExprAsFunction returns a function for an expr. If the expr is already a function, returns expr. Otherwise, returns expr wrapper in a function with arg '.'.

func (*Function) Arg 

func (f *Function) Arg() string

Arg returns a function's formal argument.

func (*Function) Body 

func (f *Function) Body() Expr

Body returns a function's body.

func (*Function) Equal 

func (f *Function) Equal(i interface{}) bool

Equal tests two Values for equality. Any other type returns false.

func (*Function) EqualFunction 

func (f *Function) EqualFunction(g *Function) bool

Equal tests two Values for equality. Any other type returns false.

func (*Function) Eval 

func (f *Function) Eval(local Scope) (Value, error)

Eval returns the Value

func (*Function) Hash 

func (f *Function) Hash(seed uintptr) uintptr

Hash computes a hash for a Function.

func (*Function) String 

func (f *Function) String() string

String returns a string representation of the expression.

type GenericSet 

type GenericSet struct {
	// contains filtered or unexported fields
}

GenericSet is a set of Values.

func (GenericSet) Any 

func (s GenericSet) Any() Value

Any return any value from the set.

func (GenericSet) ArrayEnumerator 

func (s GenericSet) ArrayEnumerator() (OffsetValueEnumerator, bool)

func (GenericSet) CallAll added in v0.3.0 

func (s GenericSet) CallAll(arg Value) Set

func (GenericSet) Count 

func (s GenericSet) Count() int

Count returns the number of elements in the genericSet.

func (GenericSet) Enumerator 

func (s GenericSet) Enumerator() ValueEnumerator

Enumerator returns an enumerator over the Values in the genericSet.

func (GenericSet) Equal 

func (s GenericSet) Equal(v interface{}) bool

Equal tests two Sets for equality. Any other type returns false.

func (GenericSet) Eval 

func (s GenericSet) Eval(local Scope) (Value, error)

Eval returns the set.

func (GenericSet) Export 

func (s GenericSet) Export() interface{}

Export exports a genericSet as an array of exported Values.

func (GenericSet) Has 

func (s GenericSet) Has(value Value) bool

Has returns true iff the given Value is in the genericSet.

func (GenericSet) Hash 

func (s GenericSet) Hash(seed uintptr) uintptr

Hash computes a hash for a genericSet.

func (GenericSet) IsTrue 

func (s GenericSet) IsTrue() bool

Bool returns true iff the tuple has attributes.

func (GenericSet) Kind 

func (s GenericSet) Kind() int

Kind returns a number that is unique for each major kind of Value.

func (GenericSet) Less 

func (s GenericSet) Less(v Value) bool

Less returns true iff v.Kind() < genericSet.Kind() or v is a genericSet and t precedes v in a lexicographical comparison of their sorted values.

func (GenericSet) Map 

func (s GenericSet) Map(f func(v Value) Value) Set

Map maps values per f.

func (GenericSet) Negate 

func (s GenericSet) Negate() Value

Negate returns {(negateTag): s}.

func (GenericSet) OrderedValues 

func (s GenericSet) OrderedValues() []Value

OrderedValues returns Values in a canonical ordering.

func (GenericSet) Source 

func (s GenericSet) Source() parser.Scanner

Source returns a scanner locating the GenericSet's source code.

func (GenericSet) String 

func (s GenericSet) String() string

String returns a string representation of a genericSet.

func (GenericSet) Where 

func (s GenericSet) Where(p func(v Value) bool) Set

Where returns a new genericSet with all the Values satisfying predicate p.

func (GenericSet) With 

func (s GenericSet) With(value Value) Set

With returns the original genericSet with given value added. Iff the value was already present, the original genericSet is returned.

func (GenericSet) Without 

func (s GenericSet) Without(value Value) Set

Without returns the original genericSet without the given value. Iff the value was already absent, the original genericSet is returned.

type GenericTuple 

type GenericTuple struct {
	// contains filtered or unexported fields
}

GenericTuple is the default implementation of Tuple.

func (*GenericTuple) Attributes 

func (t *GenericTuple) Attributes() map[string]Value

Attributes returns attributes as a map.

func (*GenericTuple) Canonical 

func (t *GenericTuple) Canonical() Tuple

func (*GenericTuple) Count 

func (t *GenericTuple) Count() int

Count returns how many attributes are in the Tuple.

func (*GenericTuple) Enumerator 

func (t *GenericTuple) Enumerator() AttrEnumerator

Enumerator returns an enumerator over the Values in the GenericTuple.

func (*GenericTuple) Equal 

func (t *GenericTuple) Equal(v interface{}) bool

Equal tests two Tuples for equality. Any other type returns false.

func (*GenericTuple) Eval 

func (t *GenericTuple) Eval(local Scope) (Value, error)

Eval returns the tuple.

func (*GenericTuple) Export 

func (t *GenericTuple) Export() interface{}

Export exports a Tuple.

func (*GenericTuple) Get 

func (t *GenericTuple) Get(name string) (Value, bool)

Get returns the Value associated with a name, and true iff it was found.

func (*GenericTuple) HasName 

func (t *GenericTuple) HasName(name string) bool

HasName returns true iff the Tuple has an attribute with the given name.

func (*GenericTuple) Hash 

func (t *GenericTuple) Hash(seed uintptr) uintptr

Hash computes a hash for a GenericTuple.

func (*GenericTuple) IsTrue 

func (t *GenericTuple) IsTrue() bool

Bool returns true iff the tuple has attributes.

func (*GenericTuple) Kind 

func (t *GenericTuple) Kind() int

Kind returns a number that is unique for each major kind of Value.

func (*GenericTuple) Less 

func (t *GenericTuple) Less(v Value) bool

Less returns true iff v is not a number or tuple, or v is a tuple and t precedes v in a lexicographical comparison of their name/value pairs.

func (*GenericTuple) Map 

func (t *GenericTuple) Map(f func(Value) Value) Tuple

func (*GenericTuple) MustGet 

func (t *GenericTuple) MustGet(name string) Value

MustGet returns e.Get(name) or panics if an error occurs.

func (*GenericTuple) Names 

func (t *GenericTuple) Names() Names

Names returns the attribute names.

func (*GenericTuple) Negate 

func (t *GenericTuple) Negate() Value

Negate returns x if t matches {(negateTag): x} else {(negateTag): t}.

func (*GenericTuple) Project 

func (t *GenericTuple) Project(names Names) Tuple

Project returns a tuple with the given names from this tuple, or nil if any name wasn't found.

func (*GenericTuple) Source 

func (t *GenericTuple) Source() parser.Scanner

Source returns a scanner locating the GenericTuple's source code.

func (*GenericTuple) String 

func (t *GenericTuple) String() string

String returns a string representation of a Tuple.

func (*GenericTuple) With 

func (t *GenericTuple) With(name string, value Value) Tuple

With returns a Tuple with all name/Value pairs in t (except the one for the given name, if present) with the addition of the given name/Value pair.

func (*GenericTuple) Without 

func (t *GenericTuple) Without(name string) Tuple

Without returns a Tuple with all name/Value pairs in t exception the one of the given name.

type GenericTupleEnumerator 

type GenericTupleEnumerator struct {
	// contains filtered or unexported fields
}

GenericTupleEnumerator represents an enumerator over a GenericTuple.

func (*GenericTupleEnumerator) Current 

func (e *GenericTupleEnumerator) Current() (string, Value)

Current returns the enumerator's current Value.

func (*GenericTupleEnumerator) MoveNext 

func (e *GenericTupleEnumerator) MoveNext() bool

MoveNext moves the enumerator to the next Value.

type IdentExpr 

type IdentExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

IdentExpr returns the variable referenced by ident.

func NewIdentExpr 

func NewIdentExpr(scanner parser.Scanner, ident string) IdentExpr

NewIdentExpr returns a new identifier.

func (IdentExpr) Bind 

func (e IdentExpr) Bind(scope Scope, value Value) (Scope, error)

func (IdentExpr) Eval 

func (e IdentExpr) Eval(local Scope) (Value, error)

Eval returns the value from scope corresponding to the ident.

func (IdentExpr) Ident 

func (e IdentExpr) Ident() string

Ident returns the ident for the IdentExpr.

func (IdentExpr) String 

func (e IdentExpr) String() string

String returns a string representation of the expression.

type IdentLookupFailed 

type IdentLookupFailed struct {
	// contains filtered or unexported fields
}

IdentLookupFailed represents failure to lookup a scope variable.

func (IdentLookupFailed) Error 

func (e IdentLookupFailed) Error() string

type IdentPattern 

type IdentPattern struct {
	// contains filtered or unexported fields
}

func NewIdentPattern 

func NewIdentPattern(ident string) IdentPattern

func (IdentPattern) Bind 

func (p IdentPattern) Bind(scope Scope, value Value) (Scope, error)

func (IdentPattern) String 

func (p IdentPattern) String() string

type IfElseExpr 

type IfElseExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

IfElseExpr returns the tuple applied to a function. Deprecated: IfElseExpr will be removed, it should use CondExpr instead.

func (*IfElseExpr) Cond 

func (e *IfElseExpr) Cond() Expr

Cond returns the condition of the IfElseExpr.

func (*IfElseExpr) Eval 

func (e *IfElseExpr) Eval(local Scope) (Value, error)

Eval returns the ifTrue

func (*IfElseExpr) LHS 

func (e *IfElseExpr) LHS() Expr

LHS returns the LHS of the IfElseExpr.

func (*IfElseExpr) RHS 

func (e *IfElseExpr) RHS() Expr

RHS returns the RHS of the IfElseExpr.

func (*IfElseExpr) String 

func (e *IfElseExpr) String() string

String returns a string representation of the expression.

type IndexedSequenceMapExpr 

type IndexedSequenceMapExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

func (*IndexedSequenceMapExpr) Eval 

func (is *IndexedSequenceMapExpr) Eval(local Scope) (Value, error)

func (*IndexedSequenceMapExpr) String 

func (is *IndexedSequenceMapExpr) String() string

String returns a string representation of the expression.

type LHSExpr 

type LHSExpr interface {
	LHS() Expr
}

LHSExpr represents any Expr that has a LHS component.

type Less 

type Less func(a, b Value) bool

type Let 

type Let func(Value)

func (Let) Match 

func (m Let) Match(v Value) bool

type LiteralMatcher 

type LiteralMatcher struct {
	// contains filtered or unexported fields
}

func Lit 

func Lit(value Value) LiteralMatcher

func (LiteralMatcher) Match 

func (m LiteralMatcher) Match(v Value) bool

type MatchAll 

type MatchAll []Matcher

func (MatchAll) Match 

func (m MatchAll) Match(v Value) bool

type MatchFirst 

type MatchFirst []Matcher

func (MatchFirst) Match 

func (m MatchFirst) Match(v Value) bool

type MatchInt 

type MatchInt func(i int)

func (MatchInt) Match 

func (m MatchInt) Match(v Value) bool

type MatchNum 

type MatchNum func(n Number)

func (MatchNum) Match 

func (m MatchNum) Match(v Value) bool

type Matcher 

type Matcher interface {
	Match(Value) bool
}

type MissingAttrError added in v0.3.0 

type MissingAttrError struct {
	// contains filtered or unexported fields
}

func (MissingAttrError) Error added in v0.3.0 

func (m MissingAttrError) Error() string

type Names 

type Names frozen.Set

Names represents a set of names.

func CombineNames 

func CombineNames(a, b Tuple, op CombineOp) Names

CombineNames returns names from a and b according to the given mask.

func NewNames 

func NewNames(names ...string) Names

NewNames returns a new set of names with the given names.

func RelationAttrs 

func RelationAttrs(a Set) (Names, bool)

RelationAttrs returns the set of names for a relation type, or false if the set isn't a regular relation.

func (Names) Any 

func (n Names) Any() string

Any returns an arbitrary element from `n`.

func (Names) Count 

func (n Names) Count() int

Count returns the number of names in a set of names.

func (Names) Enumerator 

func (n Names) Enumerator() *NamesEnumerator

Enumerator returns an enumerator over a set of names.

func (Names) Equal 

func (n Names) Equal(i interface{}) bool

Equal returns true iff the given sets of names are equal.

func (Names) Has 

func (n Names) Has(name string) bool

Has returns true iff the given name is in the set of names.

func (Names) Hash 

func (n Names) Hash(seed uint32) uint32

Hash computes a hash value for the set of names.

func (Names) Intersect 

func (n Names) Intersect(o Names) Names

Intersect returns names in both sets.

func (Names) IsSubsetOf 

func (n Names) IsSubsetOf(o Names) bool

IsSubsetOf returns true if `n“ is a subset of `o`.

func (Names) IsTrue 

func (n Names) IsTrue() bool

Bool returns true iff there are names in the set.

func (Names) Minus 

func (n Names) Minus(o Names) Names

Minus returns names in one set not found in the other.

func (Names) Names 

func (n Names) Names() []string

Names returns a slice of the names in the set.

func (Names) OrderedNames 

func (n Names) OrderedNames() []string

Names returns a sorted slice of the names in the set.

func (Names) String 

func (n Names) String() string

String returns a string representation of the set of names.

func (Names) TheOne 

func (n Names) TheOne() string

TheOne return the single name in the set; panics otherwise.

func (Names) ToSlice 

func (n Names) ToSlice() []string

ToSlice returns a slice of the names in the set.

func (Names) With 

func (n Names) With(name string) Names

With returns a set with all the input names and the given name.

func (Names) Without 

func (n Names) Without(name string) Names

Without returns a set with all the input names, excluding the given name.

type NamesEnumerator 

type NamesEnumerator struct {
	// contains filtered or unexported fields
}

NamesEnumerator represents an enumerator over a set of names.

func (*NamesEnumerator) Current 

func (e *NamesEnumerator) Current() string

Current returns the enumerator's current Value.

func (*NamesEnumerator) MoveNext 

func (e *NamesEnumerator) MoveNext() bool

MoveNext moves the enumerator to the next Value.

type NativeFunction 

type NativeFunction struct {
	// contains filtered or unexported fields
}

NativeFunction represents a binary relation uniquely mapping inputs to outputs.

func (*NativeFunction) ArrayEnumerator added in v0.3.0 

func (*NativeFunction) ArrayEnumerator() (OffsetValueEnumerator, bool)

func (*NativeFunction) CallAll added in v0.3.0 

func (f *NativeFunction) CallAll(arg Value) Set

Call calls the NativeFunction with the given parameter.

func (*NativeFunction) Count added in v0.3.0 

func (*NativeFunction) Count() int

func (*NativeFunction) Enumerator added in v0.3.0 

func (*NativeFunction) Enumerator() ValueEnumerator

func (*NativeFunction) Equal 

func (f *NativeFunction) Equal(i interface{}) bool

Equal tests two Values for equality. Any other type returns false.

func (*NativeFunction) Eval 

func (f *NativeFunction) Eval(local Scope) (Value, error)

Eval returns the Value

func (*NativeFunction) Export 

func (f *NativeFunction) Export() interface{}

Export exports a NativeFunction.

func (*NativeFunction) Fn 

func (f *NativeFunction) Fn() func(Value) Value

Fn returns a native function's implementation.

func (*NativeFunction) Has added in v0.3.0 

func (*NativeFunction) Has(Value) bool

func (*NativeFunction) Hash 

func (f *NativeFunction) Hash(seed uintptr) uintptr

Hash computes a hash for a NativeFunction.

func (*NativeFunction) IsTrue 

func (f *NativeFunction) IsTrue() bool

Bool always returns true.

func (*NativeFunction) Kind 

func (f *NativeFunction) Kind() int

Kind returns a number that is unique for each major kind of Value.

func (*NativeFunction) Less 

func (f *NativeFunction) Less(g Value) bool

Less returns true iff g is not a number or f.number < g.number.

func (*NativeFunction) Map added in v0.3.0 

func (*NativeFunction) Map(func(Value) Value) Set

func (*NativeFunction) Name 

func (f *NativeFunction) Name() string

Name returns a native function's name.

func (*NativeFunction) Negate 

func (f *NativeFunction) Negate() Value

Negate returns {(negateTag): f}.

func (*NativeFunction) Source 

func (f *NativeFunction) Source() parser.Scanner

Source returns an empty scanner since NativeFunction doesn't have associated source code.

func (*NativeFunction) String 

func (f *NativeFunction) String() string

String returns a string representation of the expression.

func (*NativeFunction) Where added in v0.3.0 

func (*NativeFunction) Where(func(Value) bool) Set

func (*NativeFunction) With added in v0.3.0 

func (*NativeFunction) With(Value) Set

func (*NativeFunction) Without added in v0.3.0 

func (*NativeFunction) Without(Value) Set

type NestExpr 

type NestExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

NestExpr returns the relation with names grouped into a nested relation.

func (*NestExpr) AttrsToNest 

func (e *NestExpr) AttrsToNest() Names

AttrsToNest returns the attrs from the LHS to be nested.

func (*NestExpr) Eval 

func (e *NestExpr) Eval(local Scope) (Value, error)

Eval returns e.lhs with e.attrs grouped under e.attr.

func (*NestExpr) LHS 

func (e *NestExpr) LHS() Expr

LHS returns the LHS of the NestExpr.

func (*NestExpr) NestedAttr 

func (e *NestExpr) NestedAttr() Names

NestedAttr returns the attr name for the nested relations.

func (*NestExpr) String 

func (e *NestExpr) String() string

String returns a string representation of the expression.

type NoReturnError added in v0.3.0 

type NoReturnError struct {
	// contains filtered or unexported fields
}

func (NoReturnError) Error added in v0.3.0 

func (n NoReturnError) Error() string

type Number 

type Number float64

Number is a number.

func NewNumber 

func NewNumber(n float64) Number

NewNumber returns a Number for the given number.

func (Number) Bind 

func (n Number) Bind(scope Scope, value Value) (Scope, error)

func (Number) Equal 

func (n Number) Equal(v interface{}) bool

Equal tests two Values for equality. Any other type returns false.

func (Number) Eval 

func (n Number) Eval(_ Scope) (Value, error)

Eval returns the number.

func (Number) Export 

func (n Number) Export() interface{}

Export exports a Number.

func (Number) Float64 

func (n Number) Float64() float64

Float64 returns the value of the number.

func (Number) Hash 

func (n Number) Hash(seed uintptr) uintptr

Hash computes a hash for a Number.

func (Number) Int 

func (n Number) Int() (int, bool)

func (Number) IsTrue 

func (n Number) IsTrue() bool

Bool returns true iff the tuple has attributes.

func (Number) Kind 

func (n Number) Kind() int

Kind returns a number that is unique for each major kind of Value.

func (Number) Less 

func (n Number) Less(v Value) bool

Less returns true iff v is not a number or n < v.

func (Number) Negate 

func (n Number) Negate() Value

Negate returns -n.

func (Number) Source 

func (n Number) Source() parser.Scanner

Source returns a scanner locating the Number's source code.

func (Number) String 

func (n Number) String() string

String returns a string representation of a Number.

type OffsetExpr 

type OffsetExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

OffsetExpr is an expression which offsets the provided array by the provided offset

func (*OffsetExpr) Eval 

func (o *OffsetExpr) Eval(local Scope) (_ Value, err error)

func (*OffsetExpr) String 

func (o *OffsetExpr) String() string

type OffsetValueEnumerator 

type OffsetValueEnumerator interface {
	ValueEnumerator
	Offset() int
}

type OrExpr 

type OrExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

func (OrExpr) Eval 

func (e OrExpr) Eval(local Scope) (Value, error)

func (OrExpr) String 

func (e OrExpr) String() string

type Pair 

type Pair struct {
	// contains filtered or unexported fields
}

Pair represents a pair of values.

type Pattern 

type Pattern interface {
	// Require a String() method.
	fmt.Stringer

	Bind(scope Scope, value Value) (Scope, error)
}

Pattern can be inside an Expr, Expr can be a Pattern.

type PatternExpr added in v0.3.0 

type PatternExpr struct {
	// contains filtered or unexported fields
}

func NewPatternExpr added in v0.3.0 

func NewPatternExpr(pattern Pattern, expr Expr) PatternExpr

NewPatternExpr returns a new PatternExpr.

func (PatternExpr) Bind added in v0.3.0 

func (pt PatternExpr) Bind(local Scope, value Value) (Scope, error)

func (PatternExpr) Eval added in v0.3.0 

func (pt PatternExpr) Eval(local Scope) (Value, error)

func (PatternExpr) String added in v0.3.0 

func (pt PatternExpr) String() string

String returns a string representation of a PatternPair.

type RecursionExpr added in v0.3.0 

type RecursionExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

func (RecursionExpr) Eval added in v0.3.0 

func (r RecursionExpr) Eval(local Scope) (Value, error)

func (RecursionExpr) String added in v0.3.0 

func (r RecursionExpr) String() string

type ReduceExpr 

type ReduceExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

ReduceExpr represents a range of operators.

func (*ReduceExpr) Eval 

func (e *ReduceExpr) Eval(local Scope) (_ Value, err error)

Eval returns the subject

func (*ReduceExpr) String 

func (e *ReduceExpr) String() string

String returns a string representation of the expression.

type Relation 

type Relation Set

Relation is a Set that only contains Tuples, all of which map the same keys.

type SafeTailCallback added in v0.3.0 

type SafeTailCallback func(Value, Scope) (Value, error)

type SafeTailExpr added in v0.3.0 

type SafeTailExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

func (*SafeTailExpr) Eval added in v0.3.0 

func (s *SafeTailExpr) Eval(local Scope) (value Value, err error)

func (*SafeTailExpr) String added in v0.3.0 

func (s *SafeTailExpr) String() string

type Scope 

type Scope struct {
	// contains filtered or unexported fields
}

Scope represents an expression scope. 

var EmptyScope Scope

EmptyScope is the scope with no variables.

func (Scope) Count 

func (s Scope) Count() int

Count returns the number of variables in this Scope.

func (Scope) Enumerator 

func (s Scope) Enumerator() *ScopeEnumerator

Enumerator returns an enumerator over the Values in the Scope.

func (Scope) Eval 

func (s Scope) Eval(local Scope) (Value, error)

Eval evaluates an expression in a given symbol environment.

func (Scope) Get 

func (s Scope) Get(name string) (Expr, bool)

Get returns the Expr for the given name or nil.

func (Scope) MatchedUpdate 

func (s Scope) MatchedUpdate(t Scope) Scope

MatchedUpdate merges s and t. New keys are added as Update, but existing keys fail unless the new value equals the existing value

func (Scope) MatchedWith 

func (s Scope) MatchedWith(name string, expr Expr) Scope

MatchedWith returns a new scope. New keys are added as With, but existing keys fail unless the new value equals the existing value

func (Scope) MustGet 

func (s Scope) MustGet(name string) Expr

MustGet returns the Expr for the given name or panics if not found.

func (Scope) Names 

func (s Scope) Names() []string

Names returns the attribute names as a slice.

func (Scope) OrderedNames 

func (s Scope) OrderedNames() []string

OrderedNames returns the names of this tuple in sorted order.

func (Scope) Project 

func (s Scope) Project(names Names) (Scope, error)

Project returns a new scope with just names from the input scope.

func (Scope) String 

func (s Scope) String() string

func (Scope) Update 

func (s Scope) Update(t Scope) Scope

s.Update(t) merges s and t, choosing t's binding in the event of a name clash. It's like calling s.With(t0).With(t1).With(t2)... for each element of t

func (Scope) With 

func (s Scope) With(name string, expr Expr) Scope

With returns a new scope with all the old bindings and a new or replacement binding for the given name to the given Expr.

func (Scope) Without 

func (s Scope) Without(name ...string) Scope

Without returns a new scope with with all the old bindings except the ones that correspond to the provided names.

type ScopeEnumerator 

type ScopeEnumerator struct {
	// contains filtered or unexported fields
}

ScopeEnumerator represents an enumerator over a Scope.

func (ScopeEnumerator) Current 

func (e ScopeEnumerator) Current() (string, Expr)

Current returns the enumerator's current Value.

func (ScopeEnumerator) MoveNext 

func (e ScopeEnumerator) MoveNext() bool

MoveNext moves the enumerator to the next Value.

type SequenceMapExpr 

type SequenceMapExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

SequenceMapExpr returns the tuple applied to a function.

func (*SequenceMapExpr) Eval 

func (e *SequenceMapExpr) Eval(local Scope) (_ Value, err error)

Eval returns the lhs

func (*SequenceMapExpr) Fn 

func (e *SequenceMapExpr) Fn() *Function

Fn returns the function to be applied to the LHS.

func (*SequenceMapExpr) LHS 

func (e *SequenceMapExpr) LHS() Expr

LHS returns the LHS of the AtArrowExpr.

func (*SequenceMapExpr) String 

func (e *SequenceMapExpr) String() string

String returns a string representation of the expression.

type Set 

type Set interface {
	Value

	// Access
	Count() int
	Has(Value) bool
	Enumerator() ValueEnumerator

	// Transform
	With(Value) Set
	Without(Value) Set
	Map(func(Value) Value) Set
	Where(func(Value) bool) Set
	CallAll(Value) Set

	ArrayEnumerator() (OffsetValueEnumerator, bool)
}

Set represents a Set of Values.

func CanonicalSet 

func CanonicalSet(s Set) Set

func Concatenate 

func Concatenate(a, b Set) (Set, error)

Concatenate is equivalent to a <&> (b => . + {.@ + a count}). Naturally, this assumes that every element in b is a tuple with at least an '@' attribute, which is numeric.

E.g., [1, 2] + [3] = [1, 2, 3]; "hell" + "o" = "hello"

func Difference 

func Difference(a, b Set) Set

Difference returns every Value from the first Set that is not in the second.

func GenericJoin 

func GenericJoin(
	a, b Set,
	getKey func(value Value) Value,
	join func(key Value, a, b Set) Set,
) Set

GenericJoin joins two sets using a key and a joiner

func Intersect 

func Intersect(a, b Set) Set

Intersect returns every Value from a that is also in b.

func Join 

func Join(a, b Set) Set

Join returns the relation join of a and b. Defn: Join(a{x…,y…}, b{y…,z…}) = ∀{x…,y…,z…}: {x…,y…} ∈ a ∧ {y…,z…} ∈ b 

for mutually disjoint x…, y…, z…

func NConcatenate 

func NConcatenate(a Set, bs ...Set) (Set, error)

func NIntersect 

func NIntersect(a Set, bs ...Set) Set

func NUnion 

func NUnion(sets ...Set) Set

func Nest 

func Nest(a Set, attrs Names, attr string) Set

Nest groups the given attributes into nested relations.

func NewArray 

func NewArray(values ...Value) Set

NewArray constructs an array as a relation.

func NewBool 

func NewBool(b bool) Set

NewBool constructs a bool as a relation.

func NewBytes 

func NewBytes(b []byte) Set

NewBytes constructs an array as a relation.

func NewDict 

func NewDict(allowDupKeys bool, entries ...DictEntryTuple) Set

NewDict constructs a dict as a relation {|@, @value|...}.

func NewOffsetArray 

func NewOffsetArray(offset int, values ...Value) Set

NewArray constructs an array as a relation.

func NewOffsetBytes 

func NewOffsetBytes(b []byte, offset int) Set

NewBytes constructs an array as a relation.

func NewOffsetString 

func NewOffsetString(s []rune, offset int) Set

NewString constructs an array as a relation.

func NewSet 

func NewSet(values ...Value) Set

NewSet constructs a genericSet from a set of Values.

func NewSetFrom 

func NewSetFrom(intfs ...interface{}) (Set, error)

NewSetFrom constructs a genericSet from interfaces.

func NewString 

func NewString(s []rune) Set

NewString constructs an array as a relation.

func PowerSet 

func PowerSet(s Set) Set

PowerSet computes the power set of a set.

func Rank added in v0.3.0 

func Rank(s Set, rankerf func(v Tuple) Tuple) (Set, error)

Rank ...

func Reduce 

func Reduce(
	a Set,
	getKey func(value Value) Value,
	reduce func(key Value, tuples Set) Set,
) Set

Reduce reduces a set using the given key and reducer functions.

func SymmetricDifference 

func SymmetricDifference(a, b Set) Set

SymmetricDifference returns Values in either Set, but not in both.

func Union 

func Union(a, b Set) Set

Union returns every Values that is in either input Set or both.

func Unnest 

func Unnest(a Set, attr string) Set

Unnest unpacks the attributes of a nested relation into the outer relation.

type SetExpr 

type SetExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

SetExpr returns the tuple or set with a single field replaced by an expression.

func (*SetExpr) Elements 

func (e *SetExpr) Elements() []Expr

Elements returns a Set's elements.

func (*SetExpr) Eval 

func (e *SetExpr) Eval(local Scope) (Value, error)

Eval returns the subject

func (*SetExpr) String 

func (e *SetExpr) String() string

String returns a string representation of the expression.

type SetMatcher 

type SetMatcher struct {
	// contains filtered or unexported fields
}

func NewSetMatcher 

func NewSetMatcher(elem Matcher) SetMatcher

func (SetMatcher) Match 

func (m SetMatcher) Match(v Value) bool

type String 

type String struct {
	// contains filtered or unexported fields
}

String is a set of Values.

func AsString 

func AsString(s Set) (String, bool)

func (String) ArrayEnumerator 

func (s String) ArrayEnumerator() (OffsetValueEnumerator, bool)

func (String) CallAll added in v0.3.0 

func (s String) CallAll(arg Value) Set

func (String) Count 

func (s String) Count() int

Count returns the number of elements in the String.

func (String) Enumerator 

func (s String) Enumerator() ValueEnumerator

Enumerator returns an enumerator over the Values in the String.

func (String) Equal 

func (s String) Equal(v interface{}) bool

Equal tests two Sets for equality. Any other type returns false.

func (String) Eval 

func (s String) Eval(_ Scope) (Value, error)

Eval returns the string.

func (String) Export 

func (s String) Export() interface{}

Export exports a String as a string.

func (String) Has 

func (s String) Has(value Value) bool

Has returns true iff the given Value is in the String.

func (String) Hash 

func (s String) Hash(seed uintptr) uintptr

Hash computes a hash for a String.

func (String) IsTrue 

func (s String) IsTrue() bool

Bool returns true iff the tuple has attributes.

func (String) Kind 

func (s String) Kind() int

Kind returns a number that is unique for each major kind of Value.

func (String) Less 

func (s String) Less(v Value) bool

Less returns true iff v is not a number or tuple, or v is a tuple and t precedes v in a lexicographical comparison of their name/value pairs.

func (String) Map 

func (s String) Map(f func(v Value) Value) Set

Map maps values per f.

func (String) Negate 

func (s String) Negate() Value

Negate returns {(negateTag): s}.

func (String) Source 

func (s String) Source() parser.Scanner

Source returns a scanner locating the String's source code.

func (String) String 

func (s String) String() string

String returns a string representation of a String.

func (String) Where 

func (s String) Where(p func(v Value) bool) Set

Where returns a new String with all the Values satisfying predicate p.

func (String) With 

func (s String) With(value Value) Set

With returns the original String with given value added. Iff the value was already present, the original String is returned.

func (String) Without 

func (s String) Without(value Value) Set

Without returns the original String without the given value. Iff the value was already absent, the original String is returned.

type StringCharTuple 

type StringCharTuple struct {
	// contains filtered or unexported fields
}

StringCharTuple represents a tuple of the form (@: at, @char: char).

func NewStringCharTuple 

func NewStringCharTuple(at int, char rune) StringCharTuple

NewStringCharTuple constructs a CharTuple.

func (StringCharTuple) Attributes 

func (t StringCharTuple) Attributes() map[string]Value

Attributes returns attributes as a map.

func (StringCharTuple) Count 

func (t StringCharTuple) Count() int

Count returns how many attributes are in the Tuple.

func (StringCharTuple) Enumerator 

func (t StringCharTuple) Enumerator() AttrEnumerator

Enumerator returns an enumerator over the Values in the CharTuple.

func (StringCharTuple) Equal 

func (t StringCharTuple) Equal(v interface{}) bool

Equal tests two Tuples for equality. Any other type returns false.

func (StringCharTuple) Eval 

func (t StringCharTuple) Eval(local Scope) (Value, error)

Eval returns the tuple.

func (StringCharTuple) Export 

func (t StringCharTuple) Export() interface{}

Export exports a Tuple.

func (StringCharTuple) Get 

func (t StringCharTuple) Get(name string) (Value, bool)

Get returns the Value associated with a name, and true iff it was found.

func (StringCharTuple) HasName 

func (t StringCharTuple) HasName(name string) bool

HasName returns true iff the Tuple has an attribute with the given name.

func (StringCharTuple) Hash 

func (t StringCharTuple) Hash(seed uintptr) uintptr

Hash computes a hash for a CharTuple.

func (StringCharTuple) IsTrue 

func (t StringCharTuple) IsTrue() bool

Bool returns true iff the tuple has attributes.

func (StringCharTuple) Kind 

func (t StringCharTuple) Kind() int

Kind returns a number that is unique for each major kind of Value.

func (StringCharTuple) Less 

func (t StringCharTuple) Less(v Value) bool

Less returns true iff v is not a number or tuple, or v is a tuple and t precedes v in a lexicographical comparison of their name/value pairs.

func (StringCharTuple) Map 

func (t StringCharTuple) Map(f func(Value) Value) Tuple

func (StringCharTuple) MustGet 

func (t StringCharTuple) MustGet(name string) Value

MustGet returns e.Get(name) or panics if an error occurs.

func (StringCharTuple) Names 

func (t StringCharTuple) Names() Names

Names returns the attribute names.

func (StringCharTuple) Negate 

func (t StringCharTuple) Negate() Value

func (StringCharTuple) Project 

func (t StringCharTuple) Project(names Names) Tuple

Project returns a tuple with the given names from this tuple, or nil if any name wasn't found.

func (StringCharTuple) Source 

func (t StringCharTuple) Source() parser.Scanner

Source returns a scanner locating the StringCharTuple's source code.

func (StringCharTuple) String 

func (t StringCharTuple) String() string

String returns a string representation of a Tuple.

func (StringCharTuple) With 

func (t StringCharTuple) With(name string, value Value) Tuple

With returns a Tuple with all name/Value pairs in t (except the one for the given name, if present) with the addition of the given name/Value pair.

func (StringCharTuple) Without 

func (t StringCharTuple) Without(name string) Tuple

Without returns a Tuple with all name/Value pairs in t exception the one of the given name.

type StringCharTupleExpr 

type StringCharTupleExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

StringCharTupleExpr represents an expr that evaluates to a StringCharTuple.

func NewStringCharTupleExpr 

func NewStringCharTupleExpr(scanner parser.Scanner, at, char Expr) StringCharTupleExpr

NewStringCharTupleExpr returns a new dictEntryTupleExpr.

func (StringCharTupleExpr) Eval 

func (e StringCharTupleExpr) Eval(local Scope) (_ Value, err error)

Eval returns the subject

func (StringCharTupleExpr) String 

func (e StringCharTupleExpr) String() string

String returns a string representation of the expression.

type Tuple 

type Tuple interface {
	Value

	// Access
	Count() int
	Get(name string) (Value, bool)
	MustGet(name string) Value
	HasName(name string) bool
	Names() Names
	Enumerator() AttrEnumerator

	// Transform
	With(name string, value Value) Tuple
	Without(name string) Tuple
	Map(func(Value) Value) Tuple
	Project(names Names) Tuple
}

Tuple is a mapping from names to Values. 

var (
	// EmptyTuple is the tuple with no attributes.
	EmptyTuple Tuple = &GenericTuple{}
)

func ASTBranchToValue 

func ASTBranchToValue(b ast.Branch) Tuple

func Merge 

func Merge(a, b Tuple) Tuple

Merge returns the merger of a and b, if possible or nil otherwise. Success requires that common names map to equal values.

func MergeLeftToRight 

func MergeLeftToRight(t Tuple, ts ...Tuple) Tuple

MergeLeftToRight returns the merger of a and b. Key from tuples to the right override tuples to the left.

func NewTuple 

func NewTuple(attrs ...Attr) Tuple

NewTuple constructs a Tuple from attrs. Passes each Val to NewValue().

func NewTupleFromMap 

func NewTupleFromMap(m map[string]interface{}) (Tuple, error)

NewTupleFromMap constructs a Tuple from a map of strings to Go values.

func NewXML 

func NewXML(tag []rune, attrs []Attr, children ...Value) Tuple

NewXML constructs an XML Tuple from the given data

type TupleBuilder 

type TupleBuilder frozen.MapBuilder

func (*TupleBuilder) Finish 

func (b *TupleBuilder) Finish() Tuple

func (*TupleBuilder) Put 

func (b *TupleBuilder) Put(name string, value Value)

type TupleExpr 

type TupleExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

TupleExpr returns a set from a slice of Exprs.

func (*TupleExpr) Attrs 

func (e *TupleExpr) Attrs() []AttrExpr

Attrs returns a Tuple's attrs.

func (*TupleExpr) Eval 

func (e *TupleExpr) Eval(local Scope) (Value, error)

Eval returns the subject

func (*TupleExpr) Get 

func (e *TupleExpr) Get(name string) Expr

Get returns the Expr for the given name or nil if not found.

func (*TupleExpr) String 

func (e *TupleExpr) String() string

String returns a string representation of the expression.

type TupleMapExpr 

type TupleMapExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

TupleMapExpr returns the tuple applied to a function.

func (*TupleMapExpr) Eval 

func (e *TupleMapExpr) Eval(local Scope) (_ Value, err error)

Eval returns the lhs

func (*TupleMapExpr) Fn 

func (e *TupleMapExpr) Fn() *Function

Fn returns the function to be applied to the LHS.

func (*TupleMapExpr) LHS 

func (e *TupleMapExpr) LHS() Expr

LHS returns the LHS of the AtArrowExpr.

func (*TupleMapExpr) String 

func (e *TupleMapExpr) String() string

String returns a string representation of the expression.

type TupleMatcher 

type TupleMatcher struct {
	// contains filtered or unexported fields
}

func NewTupleMatcher 

func NewTupleMatcher(attrs map[string]Matcher, rest Matcher) TupleMatcher

func (TupleMatcher) Match 

func (m TupleMatcher) Match(v Value) bool

type TuplePattern 

type TuplePattern struct {
	// contains filtered or unexported fields
}

func NewTuplePattern 

func NewTuplePattern(attrs ...TuplePatternAttr) TuplePattern

func (TuplePattern) Bind 

func (p TuplePattern) Bind(local Scope, value Value) (Scope, error)

func (TuplePattern) String 

func (p TuplePattern) String() string

type TuplePatternAttr added in v0.3.0 

type TuplePatternAttr struct {
	// contains filtered or unexported fields
}

func NewTuplePatternAttr added in v0.3.0 

func NewTuplePatternAttr(name string, pattern Pattern) TuplePatternAttr

func (*TuplePatternAttr) IsWildcard added in v0.3.0 

func (a *TuplePatternAttr) IsWildcard() bool

func (TuplePatternAttr) String added in v0.3.0 

func (a TuplePatternAttr) String() string

type UnaryExpr 

type UnaryExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

UnaryExpr represents a range of operators.

func (*UnaryExpr) Arg 

func (e *UnaryExpr) Arg() Expr

Arg returns the UnaryExpr's arg.

func (*UnaryExpr) Eval 

func (e *UnaryExpr) Eval(local Scope) (Value, error)

Eval returns the subject

func (*UnaryExpr) String 

func (e *UnaryExpr) String() string

String returns a string representation of the expression.

type UnnestExpr 

type UnnestExpr struct {
	ExprScanner
	// contains filtered or unexported fields
}

UnnestExpr returns the relation with names grouped into a nested relation.

func (*UnnestExpr) AttrToUnnest 

func (e *UnnestExpr) AttrToUnnest() string

AttrToUnnest returns the attr name to unnest.

func (*UnnestExpr) Eval 

func (e *UnnestExpr) Eval(local Scope) (Value, error)

Eval returns e.lhs with e.attrs grouped under e.attr.

func (*UnnestExpr) LHS 

func (e *UnnestExpr) LHS() Expr

LHS returns the LHS of the UnnestExpr.

func (*UnnestExpr) String 

func (e *UnnestExpr) String() string

String returns a string representation of the expression.

type Value 

type Value interface {
	frozen.Key

	// Values are Exprs.
	Expr

	// Kind returns a number that is unique for each major kind of Value.
	Kind() int

	// Bool returns true iff the Value is non-zero or non-empty.
	IsTrue() bool

	// Less return true iff the Value is less than v. Number < Tuple < Set.
	Less(v Value) bool

	// Negate returns the negation of the Value.
	// - For numbers, this is the arithmetic negation of the value.
	// - For the tuple {(negateTag): x}, it returns x.
	// - For all other values, x, it returns {(negateTag): x}.
	Negate() Value

	// Export converts the Value to a natural Go value.
	Export() interface{}
}

Value represents any arr.ai value.

func ASTLeafToValue 

func ASTLeafToValue(l ast.Leaf) Value

func ASTNodeToValue 

func ASTNodeToValue(n ast.Node) Value

func Call 

func Call(a, b Value, local Scope) (Value, error)

func EvalExpr 

func EvalExpr(expr Expr, local Scope) (_ Value, err error)

func NewClosure 

func NewClosure(scope Scope, f *Function) Value

NewFunction returns a new function.

func NewExprClosure 

func NewExprClosure(scope Scope, e Expr) Value

NewFunction returns a new function.

func NewNativeFunction 

func NewNativeFunction(name string, fn func(Value) Value) Value

NewNativeFunction returns a new function.

func NewNativeLambda 

func NewNativeLambda(fn func(Value) Value) Value

NewNativeLambda returns a nameless function.

func NewValue 

func NewValue(v interface{}) (Value, error)

NewValue constructs a new value from a Go value.

func OrderBy 

func OrderBy(s Set, key func(v Value) (Value, error), less func(a, b Value) bool) ([]Value, error)

OrderBy returns a slice with the sets Values sorted by the given key.

func SafeSetCall added in v0.3.0 

func SafeSetCall(s Set, arg Value) (Value, error)

func SetAny added in v0.3.0 

func SetAny(s Set) Value

func SetCall added in v0.3.0 

func SetCall(s Set, arg Value) Value

SetCall does a CallAll to a Set and panics when there's less or more than 1 value.

func UnmarshalFromJSON 

func UnmarshalFromJSON(data []byte) (Value, error)

UnmarshalFromJSON unmarshals the given value from JSON interpreting escaped sets ({"{||}": s}) accordingly.

func ValueEnumeratorToSlice 

func ValueEnumeratorToSlice(e ValueEnumerator) []Value

ValueEnumeratorToSlice transcribes its Values in a slice.

type ValueEnumerator 

type ValueEnumerator interface {
	MoveNext() bool
	Current() Value
}

ValueEnumerator enumerates Values.

func OrderedValueEnumerator 

func OrderedValueEnumerator(e ValueEnumerator, less Less) ValueEnumerator

type ValueList 

type ValueList []Value

ValueList represents a []Value for use in sort.Sort().

func (ValueList) Len 

func (vl ValueList) Len() int

func (ValueList) Less 

func (vl ValueList) Less(i, j int) bool

func (ValueList) Swap 

func (vl ValueList) Swap(i, j int)

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