Documentation ¶
Overview ¶
Package adt represents partially and fully evaluated CUE types.
This package introduces several categories of types that indicate some set of values that may be used in a certain situation. Concrete types may belong to multiple categories.
Abstract Types ¶
The following types describe the a place where a value may be used:
Decl a value than can be used as a StructLit element. Elem a value than can be used as a ListLit element. Expr represents an Expr in the CUE grammar. Value a fully evaluated value that has no references (except for children in composite values). Node any of the above values.
The following types categorize nodes by function:
Resolver a reference to position in the result tree. Evaluator evaluates to 1 value. Yielder evaluates to 0 or more values. Validator validates another value.
Reference resolution algorithm ¶
A Resolver is resolved within the context of an Environment. In CUE, a reference is evaluated by substituting it with a copy of the value to which it refers. If the copied value itself contains references we can distinguish two different cases. References that refer to values within the copied reference (not regarding selectors) will henceforth point to the copied node. References that point to outside the referened value will keep referring to their original value.
a: b: { c: int d: c e: f } f: 4 g: a.b { // d.c points to inside the referred value, e.f, not. c: 3 }
The implementation doesn't actually copy referred values, but rather resolves references with the aid of an Environment. During compile time, each references is associated with the label and a number indicating in which parent scope (offset from the current) this label needs to be looked up. An Environment keeps track of the point at which a value was referenced, providing enough information to look up the labeled value. This Environment is the identical for all references within a fields conjunct. Often, an Environment can even be shared among conjuncts.
Values ¶
Values are fully evaluated expressions. As this means that all references will have been eliminated, Values are fully defined without the need for an Environment. Additionally, Values represent a fully evaluated form, stripped of any comprehensions, optional fields or embeddings.
Index ¶
- Constants
- func IsConcrete(v Value) bool
- func Pos(n Node) token.Pos
- type Acceptor
- type BasicType
- type BinaryExpr
- type Bool
- type Bottom
- type BoundExpr
- type BoundValue
- type Builtin
- type BuiltinValidator
- type BulkOptionalField
- type Bytes
- type CallExpr
- type Concreteness
- type Config
- type Conjunct
- type Conjunction
- type Decl
- type Disjunct
- type Disjunction
- type DisjunctionExpr
- type DynamicField
- type DynamicReference
- type Elem
- type Ellipsis
- type Environment
- type ErrorCode
- type Evaluator
- type Expr
- type Feature
- func (f Feature) Index() int
- func (f Feature) IsDef() bool
- func (f Feature) IsHidden() bool
- func (f Feature) IsInt() bool
- func (f Feature) IsRegular() bool
- func (f Feature) IsString() bool
- func (f Feature) IsValid() bool
- func (f Feature) SelectorString(index StringIndexer) string
- func (f Feature) StringValue(index StringIndexer) string
- func (f Feature) ToValue(ctx *OpContext) Value
- func (f Feature) Typ() FeatureType
- type FeatureType
- type Field
- type FieldReference
- type ForClause
- type ID
- type IfClause
- type ImportReference
- type IndexExpr
- type Interpolation
- type Kind
- type LabelReference
- type LetClause
- type LetReference
- type ListLit
- type ListMarker
- type Node
- type NodeLink
- type Null
- type Num
- type Op
- type OpContext
- func (c *OpContext) AddBottom(b *Bottom)
- func (c *OpContext) AddErr(err errors.Error) *Bottom
- func (c *OpContext) AddErrf(format string, args ...interface{}) *Bottom
- func (c *OpContext) AddPosition(n Node)
- func (c *OpContext) BoolValue(v Value) bool
- func (c *OpContext) Concrete(env *Environment, x Expr, msg interface{}) (result Value, complete bool)
- func (c *OpContext) Elems(v Value) []*Vertex
- func (c *OpContext) Env(upCount int32) *Environment
- func (c *OpContext) Err() *Bottom
- func (c *OpContext) Evaluate(env *Environment, x Expr) (result Value, complete bool)
- func (c *OpContext) HasErr() bool
- func (c *OpContext) Impl() Runtime
- func (c *OpContext) Int64(v Value) int64
- func (c *OpContext) IsTentative() bool
- func (c *OpContext) Label(x Value) Feature
- func (c *OpContext) MarkPositions() int
- func (c *OpContext) NewErrf(format string, args ...interface{}) *Bottom
- func (c *OpContext) NewInt64(n int64, sources ...Node) Value
- func (c *OpContext) NewList(values ...Value) *Vertex
- func (c *OpContext) NewPosf(p token.Pos, format string, args ...interface{}) *ValueError
- func (c *OpContext) NewString(s string) Value
- func (c *OpContext) Newf(format string, args ...interface{}) *ValueError
- func (c *OpContext) PopArc(saved *Vertex)
- func (c *OpContext) PopState(s frame) *Bottom
- func (c *OpContext) Pos() token.Pos
- func (c *OpContext) PushArc(v *Vertex) (saved *Vertex)
- func (c *OpContext) PushState(env *Environment, src ast.Node) (saved frame)
- func (c *OpContext) ReleasePositions(p int)
- func (c *OpContext) Resolve(env *Environment, r Resolver) (*Vertex, *Bottom)
- func (c *OpContext) Source() ast.Node
- func (c *OpContext) Str(x Node) string
- func (c *OpContext) StringLabel(s string) Feature
- func (c *OpContext) StringValue(v Value) string
- func (c *OpContext) ToBytes(v Value) []byte
- func (c *OpContext) ToString(v Value) string
- func (c *OpContext) Validate(check Validator, value Value) *Bottom
- func (c *OpContext) Yield(env *Environment, y Yielder, f YieldFunc) *Bottom
- type OptionalField
- type OptionalType
- type Resolver
- type Runtime
- type SelectorExpr
- type SliceExpr
- type String
- type StringIndexer
- type StructLit
- type StructMarker
- type Top
- type UnaryExpr
- type Unifier
- type Validator
- type Value
- type ValueClause
- type ValueError
- type Vertex
- func (v *Vertex) Accept(ctx *OpContext, f Feature) bool
- func (v *Vertex) AddChildError(recursive *Bottom)
- func (v *Vertex) AddConjunct(c Conjunct) *Bottom
- func (v *Vertex) AddErr(ctx *OpContext, b *Bottom)
- func (v *Vertex) AddStructs(a ...*StructLit)
- func (x *Vertex) Concreteness() Concreteness
- func (v *Vertex) Default() *Vertex
- func (v *Vertex) Elems() []*Vertex
- func (v *Vertex) Err(c *OpContext, state VertexStatus) *Bottom
- func (v *Vertex) Finalize(c *OpContext)
- func (v *Vertex) GetArc(f Feature) (arc *Vertex, isNew bool)
- func (v *Vertex) IsClosed(ctx *OpContext) bool
- func (v *Vertex) IsData() bool
- func (v *Vertex) IsErr() bool
- func (v *Vertex) IsList() bool
- func (v *Vertex) Kind() Kind
- func (v *Vertex) Lookup(f Feature) *Vertex
- func (v *Vertex) MatchAndInsert(ctx *OpContext, arc *Vertex)
- func (v *Vertex) OptionalTypes() OptionalType
- func (v *Vertex) Path() []Feature
- func (v *Vertex) SetValue(ctx *OpContext, state VertexStatus, value Value) *Bottom
- func (v *Vertex) Source() ast.Node
- func (v *Vertex) Status() VertexStatus
- func (v *Vertex) ToDataAll() *Vertex
- func (v *Vertex) ToDataSingle() *Vertex
- func (v *Vertex) UpdateStatus(s VertexStatus)
- type VertexStatus
- type YieldFunc
- type Yielder
Constants ¶
const MaxIndex int64 = 1<<28 - 1
MaxIndex indicates the maximum number of unique strings that are used for labeles within this CUE implementation.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Acceptor ¶
type Acceptor interface { // Accept reports whether a given field is accepted as output. // Pass an InvalidLabel to determine whether this is always open. Accept(ctx *OpContext, f Feature) bool // MatchAndInsert finds the conjuncts for optional fields, pattern // constraints, and additional constraints that match f and inserts them in // arc. Use f is 0 to match all additional constraints only. MatchAndInsert(c *OpContext, arc *Vertex) // OptionalTypes returns a bit field with the type of optional constraints // that are represented by this Acceptor. OptionalTypes() OptionalType }
Acceptor is a single interface that reports whether feature f is a valid field label for this vertex.
TODO: combine this with the StructMarker functionality?
type BasicType ¶
BasicType represents all values of a certain Kind. It can be used as a Value and Expr.
string int num bool
func (*BasicType) Concreteness ¶
func (*BasicType) Concreteness() Concreteness
type BinaryExpr ¶
type BinaryExpr struct { Src *ast.BinaryExpr Op Op X Expr Y Expr }
BinaryExpr is a binary expression.
X + Y X & Y
func (*BinaryExpr) Source ¶
func (x *BinaryExpr) Source() ast.Node
type Bool ¶
Bool is a boolean value. It can be used as a Value and Expr.
func (*Bool) Concreteness ¶
func (*Bool) Concreteness() Concreteness
type Bottom ¶
type Bottom struct { Src ast.Node Err errors.Error Code ErrorCode HasRecursive bool ChildError bool // Err is the error of the child // Value holds the computed value so far in case Value Value }
Bottom represents an error or bottom symbol.
Although a Bottom node holds control data, it should not be created until the control information already resulted in an error.
func CombineErrors ¶
CombineErrors combines two errors that originate at the same Vertex.
func (*Bottom) Concreteness ¶
func (*Bottom) Concreteness() Concreteness
func (*Bottom) IsIncomplete ¶
func (*Bottom) Specialize ¶
type BoundValue ¶
A BoundValue is a fully evaluated unary comparator that can be used to validate other values.
<5 =~"Name$"
func (*BoundValue) Concreteness ¶
func (*BoundValue) Concreteness() Concreteness
func (*BoundValue) Kind ¶
func (x *BoundValue) Kind() Kind
func (*BoundValue) Source ¶
func (x *BoundValue) Source() ast.Node
type Builtin ¶
type Builtin struct { // TODO: make these values for better type checking. Params []Kind Result Kind Func func(c *OpContext, args []Value) Expr Package Feature Name string // REMOVE: for legacy Const string }
A Builtin is a value representing a native function call.
func (*Builtin) Concreteness ¶
func (*Builtin) Concreteness() Concreteness
Constraint only applies if Builtin is used as constraint.
type BuiltinValidator ¶
type BuiltinValidator struct { Src *ast.CallExpr Builtin *Builtin Args []Value // any but the first value }
A BuiltinValidator is a Value that results from evaluation a partial call to a builtin (using CallExpr).
strings.MinRunes(4)
func (*BuiltinValidator) Concreteness ¶
func (*BuiltinValidator) Concreteness() Concreteness
func (*BuiltinValidator) Kind ¶
func (x *BuiltinValidator) Kind() Kind
func (*BuiltinValidator) Source ¶
func (x *BuiltinValidator) Source() ast.Node
type BulkOptionalField ¶
type BulkOptionalField struct { Src *ast.Field // Elipsis or Field Filter Expr Value Expr Label Feature // for reference and formatting }
A BulkOptionalField represents a set of optional field.
[expr]: expr
func (*BulkOptionalField) Source ¶
func (x *BulkOptionalField) Source() ast.Node
type Bytes ¶
Bytes is a bytes value. It can be used as a Value and Expr.
func (*Bytes) Concreteness ¶
func (*Bytes) Concreteness() Concreteness
type Concreteness ¶
type Concreteness int
Concreteness is a measure of the level of concreteness of a value, where lower values mean more concrete.
const ( BottomLevel Concreteness = iota // Concrete indicates a concrete scalar value, list or struct. Concrete // Constraint indicates a non-concrete scalar value that is more specific, // than a top-level type. Constraint // PrimitiveType indicates a top-level specific type, for instance, string, // bytes, number, or bool. Type // Any indicates any value, or top. Any )
type Conjunct ¶
type Conjunct struct { Env *Environment // CloseID is a unique number that tracks a group of conjuncts that need // belong to a single originating definition. CloseID ID // contains filtered or unexported fields }
An Conjunct is an Environment-Expr pair. The Environment is the starting point for reference lookup for any reference contained in X.
func MakeConjunct ¶
func MakeConjunct(env *Environment, x Node, id ID) Conjunct
func MakeRootConjunct ¶
func MakeRootConjunct(env *Environment, x Node) Conjunct
MakeRootConjunct creates a conjunct from the given environment and node. It panics if x cannot be used as an expression.
type Conjunction ¶
A Conjunction is a conjunction of values that cannot be represented as a single value. It is the result of unification.
func (*Conjunction) Concreteness ¶
func (*Conjunction) Concreteness() Concreteness
func (*Conjunction) Kind ¶
func (x *Conjunction) Kind() Kind
func (*Conjunction) Source ¶
func (x *Conjunction) Source() ast.Node
type Decl ¶
type Decl interface { Node // contains filtered or unexported methods }
A Decl represents all valid StructLit elements.
type Disjunction ¶
type Disjunction struct { Src ast.Expr // Values are the non-error disjuncts of this expression. The first // NumDefault values are default values. Values []*Vertex Errors *Bottom // []bottom // NumDefaults indicates the number of default values. NumDefaults int }
A disjunction is a disjunction of values. It is the result of expanding a DisjunctionExpr if the expression cannot be represented as a single value.
func (*Disjunction) Concreteness ¶
func (*Disjunction) Concreteness() Concreteness
func (*Disjunction) Default ¶
func (d *Disjunction) Default() Value
func (*Disjunction) Kind ¶
func (x *Disjunction) Kind() Kind
func (*Disjunction) Source ¶
func (x *Disjunction) Source() ast.Node
type DisjunctionExpr ¶
type DisjunctionExpr struct { Src *ast.BinaryExpr Values []Disjunct HasDefaults bool }
A Disjunction represents a disjunction, where each disjunct may or may not be marked as a default.
func (*DisjunctionExpr) Source ¶
func (x *DisjunctionExpr) Source() ast.Node
type DynamicField ¶
A DynamicField represents a regular field for which the key is computed.
"\(expr)": expr (expr): expr
func (*DynamicField) IsOptional ¶
func (x *DynamicField) IsOptional() bool
func (*DynamicField) Source ¶
func (x *DynamicField) Source() ast.Node
type DynamicReference ¶
type DynamicReference struct { Src *ast.Ident UpCount int32 Label Expr // TODO: only use aliases and store the actual expression only in the scope. // The feature is unique for every instance. This will also allow dynamic // fields to be ordered among normal fields. // // This could also be used to assign labels to embedded values, if they // don't match a label. Alias Feature }
A DynamicReference is like a LabelReference, but with a computed label.
X=(x): X X="\(x)": X
func (*DynamicReference) Source ¶
func (x *DynamicReference) Source() ast.Node
type Elem ¶
type Elem interface { Decl // contains filtered or unexported methods }
An Elem represents all value ListLit elements.
All Elem values can be used as a Decl.
type Environment ¶
type Environment struct { Up *Environment Vertex *Vertex // DynamicLabel is only set when instantiating a field from a pattern // constraint. It is used to resolve label references. DynamicLabel Feature // Cyclic indicates a structural cycle was detected for this conjunct or one // of its ancestors. Cyclic bool // Deref keeps track of nodes that should dereference to Vertex. It is used // for detecting structural cycle. // // The detection algorithm is based on Tomabechi's quasi-destructive graph // unification. This detection requires dependencies to be resolved into // fully dereferenced vertices. This is not the case in our algorithm: // the result of evaluating conjuncts is placed into dereferenced vertices // _after_ they are evaluated, but the Environment still points to the // non-dereferenced context. // // In order to be able to detect structural cycles, we need to ensure that // at least one node that is part of a cycle in the context in which // conjunctions are evaluated dereferences correctly. // // The only field necessary to detect a structural cycle, however, is // the Status field of the Vertex. So rather than dereferencing a node // proper, it is sufficient to copy the Status of the dereferenced nodes // to these nodes (will always be EvaluatingArcs). Deref []*Vertex // Cycles contains vertices for which cycles are detected. It is used // for tracking self-references within structural cycles. // // Unlike Deref, Cycles is not incremented with child nodes. // TODO: Cycles is always a tail end of Deref, so this can be optimized. Cycles []*Vertex // contains filtered or unexported fields }
An Environment links the parent scopes for identifier lookup to a composite node. Each conjunct that make up node in the tree can be associated with a different environment (although some conjuncts may share an Environment).
type ErrorCode ¶
type ErrorCode int
ErrorCode indicates the type of error. The type of error may influence control flow. No other aspects of an error may influence control flow.
const ( // An EvalError is a fatal evaluation error. EvalError ErrorCode = iota // A UserError is a fatal error originating from the user. UserError // NotExistError is used to indicate a value does not exist. // Mostly used for legacy reasons. NotExistError // StructuralCycleError means a structural cycle was found. Structural // cycles are permanent errors, but they are not passed up recursively, // as a unification of a value with a structural cycle with one that // doesn't may still give a useful result. StructuralCycleError // IncompleteError means an evaluation could not complete because of // insufficient information that may still be added later. IncompleteError // A CycleError indicates a reference error. It is considered to be // an incomplete error, as reference errors may be broken by providing // a concrete value. CycleError )
type Evaluator ¶
type Evaluator interface { Node // contains filtered or unexported methods }
An Evaluator provides a method to convert to a value.
type Expr ¶
type Expr interface { Elem // contains filtered or unexported methods }
An Expr corresponds to an ast.Expr.
All Expr values can be used as an Elem or Decl.
type Feature ¶
type Feature uint32
A Feature is an encoded form of a label which comprises a compact representation of an integer or string label as well as a label type.
const InvalidLabel Feature = 0x7 // 0xb111
InvalidLabel is an encoding of an erroneous label.
func MakeIdentLabel ¶
func MakeIdentLabel(r StringIndexer, s string) Feature
MakeIdentLabel creates a label for the given identifier.
func MakeStringLabel ¶
func MakeStringLabel(r StringIndexer, s string) Feature
MakeStringLabel creates a label for the given string.
func (Feature) IsDef ¶
IsDef reports whether the label is a definition (an identifier starting with # or #_.
func (Feature) IsHidden ¶
IsHidden reports whether this label is hidden (an identifier starting with _ or #_).
func (Feature) SelectorString ¶
func (f Feature) SelectorString(index StringIndexer) string
SelectorString reports the shortest string representation of f when used as a selector.
func (Feature) StringValue ¶
func (f Feature) StringValue(index StringIndexer) string
StringValue reports the string value of f, which must be a string label.
type FeatureType ¶
type FeatureType int8
A FeatureType indicates the type of label.
const ( StringLabel FeatureType = 0 // 0b000 IntLabel FeatureType = 1 // 0b001 DefinitionLabel FeatureType = 3 // 0b011 HiddenLabel FeatureType = 6 // 0b110 HiddenDefinitionLabel FeatureType = 7 // 0b111 )
type Field ¶
Field represents a field with a fixed label. It can be a regular field, definition or hidden field.
foo: bar #foo: bar _foo: bar
Legacy:
Foo :: bar
type FieldReference ¶
A FieldReference represents a lexical reference to a field.
a
func (*FieldReference) Source ¶
func (x *FieldReference) Source() ast.Node
type ForClause ¶
A ForClause represents a for clause of a comprehension. It can be used as a struct or list element.
for k, v in src {}
type IfClause ¶
An IfClause represents an if clause of a comprehension. It can be used as a struct or list element.
if cond {}
type ImportReference ¶
type ImportReference struct { Src *ast.Ident ImportPath Feature Label Feature // for informative purposes }
An ImportReference refers to an imported package.
import "strings" strings.ToLower("Upper")
func (*ImportReference) Source ¶
func (x *ImportReference) Source() ast.Node
type Interpolation ¶
type Interpolation struct { Src *ast.Interpolation K Kind // string or bytes Parts []Expr // odd: strings, even sources }
An Interpolation is a string interpolation.
"a \(b) c"
func (*Interpolation) Source ¶
func (x *Interpolation) Source() ast.Node
type Kind ¶
type Kind uint16
Kind reports the Value kind.
const ( NullKind Kind = (1 << iota) BoolKind IntKind FloatKind StringKind BytesKind ListKind StructKind NumberKind = IntKind | FloatKind BottomKind Kind = 0 NumKind = IntKind | FloatKind TopKind Kind = (allKinds - 1) // all kinds, but not references ScalarKinds = NullKind | BoolKind | IntKind | FloatKind | StringKind | BytesKind )
func (Kind) IsAnyOf ¶
IsAnyOf reports whether k is any of the given kinds.
For instances, k.IsAnyOf(String|Bytes) reports whether k overlaps with the String or Bytes kind.
func (Kind) String ¶
String returns the representation of the Kind as a CUE expression. For example:
(IntKind|ListKind).String()
will return:
(int|[...])
func (Kind) TypeString ¶
TypeString is like String, but returns a string representation of a valid CUE type.
type LabelReference ¶
A LabelReference refers to the string or integer value of a label.
[X=Pattern]: b: X
func (*LabelReference) Source ¶
func (x *LabelReference) Source() ast.Node
type LetReference ¶
type LetReference struct { Src *ast.Ident UpCount int32 Label Feature // for informative purposes X Expr }
A LetReference evaluates a let expression in its original environment.
let X = x
func (*LetReference) Source ¶
func (x *LetReference) Source() ast.Node
type ListMarker ¶
func (*ListMarker) Concreteness ¶
func (x *ListMarker) Concreteness() Concreteness
func (*ListMarker) Kind ¶
func (x *ListMarker) Kind() Kind
func (*ListMarker) Source ¶
func (x *ListMarker) Source() ast.Node
type NodeLink ¶
type NodeLink struct {
Node *Vertex
}
A NodeLink is used during computation to refer to an existing Vertex. It is used to signal a potential cycle or reference. Note that a NodeLink may be used as a value. This should be taken into account.
func (*NodeLink) Concreteness ¶
func (x *NodeLink) Concreteness() Concreteness
type Null ¶
Null represents null. It can be used as a Value and Expr.
func (*Null) Concreteness ¶
func (*Null) Concreteness() Concreteness
type Num ¶
type Num struct { Src ast.Node K Kind // needed? X apd.Decimal // Is integer if the apd.Decimal is an integer. }
Num is a numeric value. It can be used as a Value and Expr.
func (*Num) Concreteness ¶
func (*Num) Concreteness() Concreteness
type Op ¶
type Op int
Op indicates the operation at the top of an expression tree of the expression use to evaluate a value.
const ( NoOp Op = iota AndOp OrOp SelectorOp IndexOp SliceOp CallOp BoolAndOp BoolOrOp EqualOp NotOp NotEqualOp LessThanOp LessEqualOp GreaterThanOp GreaterEqualOp MatchOp NotMatchOp AddOp SubtractOp MultiplyOp FloatQuotientOp IntQuotientOp IntRemainderOp IntDivideOp IntModuloOp InterpolationOp )
Values of Op.
type OpContext ¶
type OpContext struct {
// contains filtered or unexported fields
}
An OpContext associates a Runtime and Unifier to allow evaluating the types defined in this package. It tracks errors provides convenience methods for evaluating values.
func NewContext ¶
NewContext creates an operation context.
func (*OpContext) AddErr ¶
AddErr records an error in OpContext. It returns errors collected so far.
func (*OpContext) AddErrf ¶
AddErrf records an error in OpContext. It returns errors collected so far.
func (*OpContext) AddPosition ¶
func (*OpContext) Concrete ¶
func (c *OpContext) Concrete(env *Environment, x Expr, msg interface{}) (result Value, complete bool)
Concrete returns the concrete value of x after evaluating it. msg is used to mention the context in which an error occurred, if any.
func (*OpContext) Env ¶
func (c *OpContext) Env(upCount int32) *Environment
func (*OpContext) Evaluate ¶
func (c *OpContext) Evaluate(env *Environment, x Expr) (result Value, complete bool)
Evaluate evaluates an expression within the given environment and indicates whether the result is complete. It will always return a non-nil result.
func (*OpContext) HasErr ¶
HasErr reports whether any error was reported, including whether value was incomplete.
func (*OpContext) IsTentative ¶
If IsTentative is set, evaluation of an arc should not finalize to non-concrete values.
func (*OpContext) MarkPositions ¶
MarkPositions marks the current position stack.
func (*OpContext) NewErrf ¶
NewErrf creates a *Bottom value and returns it. The returned uses the current source as the point of origin of the error.
func (*OpContext) NewPosf ¶
func (c *OpContext) NewPosf(p token.Pos, format string, args ...interface{}) *ValueError
func (*OpContext) Newf ¶
func (c *OpContext) Newf(format string, args ...interface{}) *ValueError
func (*OpContext) PushArc ¶
PushArc signals c that arc v is currently being processed for the purpose of error reporting. PopArc should be called with the returned value once processing of v is completed.
func (*OpContext) PushState ¶
func (c *OpContext) PushState(env *Environment, src ast.Node) (saved frame)
func (*OpContext) ReleasePositions ¶
ReleasePositions sets the position state to one from a call to MarkPositions.
func (*OpContext) Resolve ¶
func (c *OpContext) Resolve(env *Environment, r Resolver) (*Vertex, *Bottom)
Resolve finds a node in the tree.
Should only be used to insert Conjuncts. TODO: perhaps only return Conjuncts and error.
func (*OpContext) StringLabel ¶
StringLabel converts s to a string label.
func (*OpContext) StringValue ¶
type OptionalField ¶
An OptionalField represents an optional regular field.
foo?: expr
func (*OptionalField) Source ¶
func (x *OptionalField) Source() ast.Node
type OptionalType ¶
type OptionalType int
OptionalType is a bit field of the type of optional constraints in use by an Acceptor.
const ( HasField OptionalType = 1 << iota // X: T HasDynamic // (X): T or "\(X)": T HasPattern // [X]: T HasAdditional // ...T IsOpen // Defined for all fields )
type Resolver ¶
type Resolver interface { Node // contains filtered or unexported methods }
A Resolver represents a reference somewhere else within a tree that resolves a value.
type Runtime ¶
type Runtime interface { // StringIndexer allows for converting string labels to and from a // canonical numeric representation. StringIndexer // LoadImport loads a unique Vertex associated with a given import path. It // returns an error if no import for this package could be found. LoadImport(importPath string) (*Vertex, errors.Error) // StoreType associates a CUE expression with a Go type. StoreType(t reflect.Type, src ast.Expr, expr Expr) // LoadType retrieves a previously stored CUE expression for a given Go // type if available. LoadType(t reflect.Type) (src ast.Expr, expr Expr, ok bool) }
Runtime defines an interface for low-level representation conversion and lookup.
type SelectorExpr ¶
type SelectorExpr struct { Src *ast.SelectorExpr X Expr Sel Feature }
A SelectorExpr looks up a fixed field in an expression.
X.Sel
func (*SelectorExpr) Source ¶
func (x *SelectorExpr) Source() ast.Node
type String ¶
String is a string value. It can be used as a Value and Expr.
func (*String) Concreteness ¶
func (*String) Concreteness() Concreteness
type StringIndexer ¶
type StringIndexer interface { // ToIndex returns a unique positive index for s (0 < index < 2^28-1). // // For each pair of strings s and t it must return the same index if and // only if s == t. StringToIndex(s string) (index int64) // ToString returns a string s for index such that ToIndex(s) == index. IndexToString(index int64) string }
A StringIndexer coverts strings to and from an index that is unique for a given string.
type StructMarker ¶
type StructMarker struct { // NeedClose is used to signal that the evaluator should close this struct. // It is only set by the close builtin. NeedClose bool }
func (*StructMarker) Concreteness ¶
func (x *StructMarker) Concreteness() Concreteness
func (*StructMarker) Kind ¶
func (x *StructMarker) Kind() Kind
func (*StructMarker) Source ¶
func (x *StructMarker) Source() ast.Node
type Top ¶
Top represents all possible values. It can be used as a Value and Expr.
func (*Top) Concreteness ¶
func (*Top) Concreteness() Concreteness
type Unifier ¶
type Unifier interface { // Unify fully unifies all values of a Vertex to completion and stores // the result in the Vertex. If Unify was called on v before it returns // the cached results. Unify(c *OpContext, v *Vertex, state VertexStatus) // error or bool? // Evaluate returns the evaluated value associated with v. It may return a // partial result. That is, if v was not yet unified, it may return a // concrete value that must be the result assuming the configuration has no // errors. // // This semantics allows CUE to break reference cycles in a straightforward // manner. // // Vertex v must still be evaluated at some point to catch the underlying // error. // Evaluate(c *OpContext, v *Vertex) Value }
A Unifier implements a strategy for CUE's unification operation. It must handle the following aspects of CUE evaluation:
- Structural and reference cycles
- Non-monotic validation
- Fixed-point computation of comprehension
type Validator ¶
type Validator interface { Value // contains filtered or unexported methods }
A Validator validates a Value. All Validators are Values.
func SimplifyValidator ¶
SimplifyValidator simplifies non-bound validators.
Currently this only checks for pure equality. In the future this can be used to simplify certain builtin validators analogously to how we simplify bounds now.
type Value ¶
type Value interface { Expr Concreteness() Concreteness Kind() Kind }
A Value represents a node in the evaluated data graph.
All Values values can also be used as a Expr.
func BinOp ¶
BinOp handles all operations except AndOp and OrOp. This includes processing unary comparators such as '<4' and '=~"foo"'.
BinOp returns nil if not both left and right are concrete.
func SimplifyBounds ¶
func SimplifyBounds(ctx *OpContext, k Kind, x, y *BoundValue) Value
SimplifyBounds collapses bounds if possible. The bound values must be concrete. It returns nil if the bound values cannot be collapsed.
k represents additional type constraints, such as `int`.
type ValueClause ¶
type ValueClause struct {
*StructLit
}
A ValueClause represents the value part of a comprehension.
func (*ValueClause) Source ¶
func (x *ValueClause) Source() ast.Node
type ValueError ¶
A ValueError is returned as a result of evaluating a value.
func (*ValueError) AddPosition ¶
func (v *ValueError) AddPosition(n Node)
func (*ValueError) Error ¶
func (e *ValueError) Error() string
func (*ValueError) InputPositions ¶
func (e *ValueError) InputPositions() (a []token.Pos)
func (*ValueError) Path ¶
func (e *ValueError) Path() (a []string)
func (*ValueError) Position ¶
func (e *ValueError) Position() token.Pos
type Vertex ¶
type Vertex struct { // Parent links to a parent Vertex. This parent should only be used to // access the parent's Label field to find the relative location within a // tree. Parent *Vertex // Label is the feature leading to this vertex. Label Feature // EvalCount keeps track of temporary dereferencing during evaluation. // If EvalCount > 0, status should be considered to be EvaluatingArcs. EvalCount int // SelfCount is used for tracking self-references. SelfCount int // Value is the value associated with this vertex. For lists and structs // this is a sentinel value indicating its kind. Value Value // ChildErrors is the collection of all errors of children. ChildErrors *Bottom // The parent of nodes can be followed to determine the path within the // configuration of this node. // Value Value Arcs []*Vertex // arcs are sorted in display order. // Conjuncts lists the structs that ultimately formed this Composite value. // This includes all selected disjuncts. // // This value may be nil, in which case the Arcs are considered to define // the final value of this Vertex. Conjuncts []Conjunct // Structs is a slice of struct literals that contributed to this value. // This information is used to compute the topological sort of arcs. Structs []*StructLit // Closed contains information about how to interpret field labels for the // various conjuncts with respect to which fields are allowed in this // Vertex. If allows all fields if it is nil. // The evaluator will first check existing fields before using this. So for // simple cases, an Acceptor can always return false to close the Vertex. Closed Acceptor // contains filtered or unexported fields }
A Vertex is a node in the value tree. It may be a leaf or internal node. It may have arcs to represent elements of a fully evaluated struct or list.
For structs, it only contains definitions and concrete fields. optional fields are dropped.
It maintains source information such as a list of conjuncts that contributed to the value.
func (*Vertex) AddChildError ¶
AddChildError updates x to record an error that occurred in one of its descendent arcs. The resulting error will record the worst error code of the current error or recursive error.
If x is not already an error, the value is recorded in the error for reference.
func (*Vertex) AddConjunct ¶
AddConjunct adds the given Conjuncts to v if it doesn't already exist.
func (*Vertex) AddStructs ¶
func (*Vertex) Concreteness ¶
func (x *Vertex) Concreteness() Concreteness
func (*Vertex) GetArc ¶
GetArc returns a Vertex for the outgoing arc with label f. It creates and ads one if it doesn't yet exist.
func (*Vertex) IsData ¶
IsData reports whether v should be interpreted in data mode. In other words, it tells whether optional field matching and non-regular fields, like definitions and hidden fields, should be ignored.
func (*Vertex) MatchAndInsert ¶
func (*Vertex) OptionalTypes ¶
func (v *Vertex) OptionalTypes() OptionalType
func (*Vertex) Path ¶
Path computes the sequence of Features leading from the root to of the instance to this Vertex.
func (*Vertex) SetValue ¶
func (v *Vertex) SetValue(ctx *OpContext, state VertexStatus, value Value) *Bottom
func (*Vertex) Status ¶
func (v *Vertex) Status() VertexStatus
func (*Vertex) ToDataAll ¶
ToDataAll returns a new v where v and all its descendents contain only the regular fields.
func (*Vertex) ToDataSingle ¶
ToDataSingle creates a new Vertex that represents just the regular fields of this vertex. Arcs are left untouched. It is used by cue.Eval to convert nodes to data on per-node basis.
func (*Vertex) UpdateStatus ¶
func (v *Vertex) UpdateStatus(s VertexStatus)
type VertexStatus ¶
type VertexStatus int8
VertexStatus indicates the evaluation progress of a Vertex.
const ( // Unprocessed indicates a Vertex has not been processed before. // Value must be nil. Unprocessed VertexStatus = iota // Evaluating means that the current Vertex is being evaluated. If this is // encountered it indicates a reference cycle. Value must be nil. Evaluating // Partial indicates that the result was only partially evaluated. It will // need to be fully evaluated to get a complete results. // // TODO: this currently requires a renewed computation. Cache the // nodeContext to allow reusing the computations done so far. Partial // EvaluatingArcs indicates that the arcs of the Vertex are currently being // evaluated. If this is encountered it indicates a structural cycle. // Value does not have to be nil EvaluatingArcs // Finalized means that this node is fully evaluated and that the results // are save to use without further consideration. Finalized )
type YieldFunc ¶
type YieldFunc func(env *Environment, s *StructLit)