eval

package
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 Go to latest Published: Sep 8, 2016 License: BSD-2-Clause Imports: 29 Imported by: 0

Documentation

Overview

Package eval handles evaluation of nodes and consists the runtime of the shell.

Index

Constants

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const (
	Return flow = iota
	Break
	Continue
)

Control flows.

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const FnPrefix = "&"

FnPrefix is the prefix for the variable names of functions. Defining a function "foo" is equivalent to setting a variable named FnPrefix + "foo".

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const (
	NoPretty = util.MinInt
)

Variables

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var (
	ErrArgs              = errors.New("args error")
	ErrInput             = errors.New("input error")
	ErrStoreNotConnected = errors.New("store not connected")
	ErrNoMatchingDir     = errors.New("no matching directory")
	ErrNotInSameGroup    = errors.New("not in the same process group")
	ErrInterrupted       = errors.New("interrupted")
)
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var (
	ErrBadGlobPattern          = errors.New("bad GlobPattern; elvish bug")
	ErrCannotDetermineUsername = errors.New("cannot determine user name from glob pattern")
)
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var (
	ErrCanOnlyAssignList          = errors.New("can only assign compatible values")
	ErrPathMustBeString           = errors.New("path must be string")
	ErrPathCannotContainColonZero = errors.New(`path cannot contain colon or \0`)
)

Errors

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var (
	ErrMustFollowWildcard   = errors.New("must follow wildcard")
	ErrModifierMustBeString = errors.New("modifier must be string")
)
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var (
	// ErrNeedIntIndex    = errors.New("need integer index")
	ErrBadIndex        = errors.New("bad index")
	ErrIndexOutOfRange = errors.New("index out of range")
)

Error definitions.

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var BuiltinSpecialNames []string

BuiltinSpecialNames contains all names of builtin special forms. It is useful for the syntax highlighter.

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var ErrArityMismatch = errors.New("arity mismatch")
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var ErrBadBase = errors.New("bad base")
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var ErrCdNoArg = errors.New("implicit cd accepts no arguments")
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var (
	ErrIndexMustBeString = errors.New("index must be string")
)
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var ErrMoreThanOneRest = errors.New("more than one @ lvalue")
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var (
	ErrOnlyStrOrRat = errors.New("only str or rat may be converted to rat")
)

Error definitions.

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var (
	ErrRoCannotBeSet = errors.New("read-only; cannot be set")
)
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var ErrStoreUnconnected = errors.New("store unconnected")

ErrStoreUnconnected is thrown by ResolveVar when a shared: variable needs to be resolved but the store is not connected.

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var (
	ErrValueMustBeString = errors.New("index must be string")
)
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var Logger = util.GetLogger("[eval] ")
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var OK = Error{nil}

OK is an alias for the zero value of Error.

Functions

func ClosePorts 

func ClosePorts(ports []*Port)

ClosePorts closes a list of Ports.

func DeepEq 

func DeepEq(a, b Value) bool

DeepEq compares two Value's deeply.

func IncIndent 

func IncIndent(indent, inc int) int

func IsListOfFnValue 

func IsListOfFnValue(v Value) error

func MakeVariableName 

func MakeVariableName(splice bool, ns string, name string) string

func NewExternalCmdExit 

func NewExternalCmdExit(name string, ws syscall.WaitStatus, pid int) error

func ParseAndFixListIndex 

func ParseAndFixListIndex(s string, n int) (bool, int, int)

ParseAndFixListIndex parses a list index and returns whether the index is a slice and "real" (-1 becomes n-1) indicies. It throws errors when the index is invalid or out of range.

func ParseVariable 

func ParseVariable(qname string) (splice bool, ns string, name string)

ParseVariable parses a variable name.

func PprintError 

func PprintError(e error)

PprintError pretty prints an error. It understands specialized error types defined in this package.

func ToBool 

func ToBool(v Value) bool

ToBool converts a Value to bool. When the Value type implements Bool(), it is used. Otherwise it is considered true.

func ToString 

func ToString(v Value) string

ToString converts a Value to String. When the Value type implements String(), it is used. Otherwise Repr(NoPretty) is used.

func WrapFn 

func WrapFn(inner interface{}) func(*EvalCtx, []Value)

WrapFn wraps an inner function into one suitable as a builtin function. It generates argument checking and conversion code according to the signature of the inner function. The inner function must accept evalCtx* as the first argument and return an exitus.

Types

type Bool 

type Bool bool

Bool represents truthness.

func (Bool) Bool 

func (b Bool) Bool() bool

func (Bool) Kind 

func (Bool) Kind() string

func (Bool) Repr 

func (b Bool) Repr(int) string

type Booler 

type Booler interface {
	Bool() bool
}

Booler is anything that can be converted to a bool.

type BuiltinFn 

type BuiltinFn struct {
	Name string
	Impl func(*EvalCtx, []Value)
}

BuiltinFn is a builtin function.

func (*BuiltinFn) Call 

func (b *BuiltinFn) Call(ec *EvalCtx, args []Value)

Call calls a builtin function.

func (*BuiltinFn) Kind 

func (*BuiltinFn) Kind() string

func (*BuiltinFn) Repr 

func (b *BuiltinFn) Repr(int) string

type Closure 

type Closure struct {
	ArgNames []string
	// The name for the rest argument. If empty, the function has fixed arity.
	// If equal to unnamedRestArg, the rest argument is unnamed but can be
	// accessed via $args.
	RestArg  string
	Op       Op
	Captured map[string]Variable
}

Closure is a closure defined in elvish script.

func (*Closure) Call 

func (c *Closure) Call(ec *EvalCtx, args []Value)

Call calls a closure.

func (*Closure) Kind 

func (*Closure) Kind() string

func (*Closure) Repr 

func (c *Closure) Repr(int) string

type EnvPathList 

type EnvPathList struct {
	sync.RWMutex
	// contains filtered or unexported fields
}

EnvPathList is a variable whose value is constructed from an environment variable by splitting at colons. Changes to it are also propagated to the corresponding environment variable. Its elements cannot contain colons or \0; attempting to put colon or \0 in its elements will result in an error.

EnvPathList implements both Value and Variable interfaces. It also satisfied ListLike.

func (*EnvPathList) Elems 

func (epl *EnvPathList) Elems() <-chan Value

func (*EnvPathList) Get 

func (epl *EnvPathList) Get() Value

func (*EnvPathList) IndexOne 

func (epl *EnvPathList) IndexOne(idx Value) Value

func (*EnvPathList) IndexSet 

func (epl *EnvPathList) IndexSet(idx, v Value)

func (*EnvPathList) Iterate 

func (epl *EnvPathList) Iterate(f func(Value) bool)

func (*EnvPathList) Kind 

func (epl *EnvPathList) Kind() string

func (*EnvPathList) Len 

func (epl *EnvPathList) Len() int

func (*EnvPathList) Repr 

func (epl *EnvPathList) Repr(indent int) string

func (*EnvPathList) Set 

func (epl *EnvPathList) Set(v Value)

type Error 

type Error struct {
	Inner error
}

Error represents runtime errors in elvish constructs.

func (Error) Bool 

func (e Error) Bool() bool

func (Error) Kind 

func (Error) Kind() string

func (Error) Repr 

func (e Error) Repr(indent int) string

type EvalCtx 

type EvalCtx struct {
	*Evaler
	// contains filtered or unexported fields
}

EvalCtx maintains an Evaler along with its runtime context. After creation an EvalCtx is not modified, and new instances are created when needed.

func NewTopEvalCtx 

func NewTopEvalCtx(ev *Evaler, name, text string, ports []*Port) *EvalCtx

NewTopEvalCtx creates a top-level evalCtx.

func (*EvalCtx) IterateInputs 

func (ec *EvalCtx) IterateInputs(f func(Value))

IterateInput calls the passed function for each input element.

func (*EvalCtx) OutputChan 

func (ec *EvalCtx) OutputChan() chan<- Value

OutputChan returns a channel onto which output can be written.

func (*EvalCtx) PCall 

func (ec *EvalCtx) PCall(f Fn, args []Value) (err error)

func (*EvalCtx) PCaptureOutput 

func (ec *EvalCtx) PCaptureOutput(f Fn, args []Value) (vs []Value, err error)

func (*EvalCtx) PEval 

func (ec *EvalCtx) PEval(op Op) (err error)

PEval evaluates an op in a protected environment so that calls to errorf are wrapped in an Error.

func (*EvalCtx) ResolveVar 

func (ec *EvalCtx) ResolveVar(ns, name string) Variable

ResolveVar resolves a variable. When the variable cannot be found, nil is returned.

type Evaler 

type Evaler struct {
	Global  Namespace
	Modules map[string]Namespace

	Stub *stub.Stub
	// contains filtered or unexported fields
}

Evaler is used to evaluate elvish sources. It maintains runtime context shared among all evalCtx instances.

func NewEvaler 

func NewEvaler(st *store.Store) *Evaler

NewEvaler creates a new Evaler.

func (*Evaler) AllExecutables 

func (ev *Evaler) AllExecutables(names chan<- string)

AllExecutables writes the names of all executable files in the search path to a channel.

func (*Evaler) Compile 

func (ev *Evaler) Compile(n *parse.Chunk) (Op, error)

Compile compiles elvish code in the global scope.

func (*Evaler) Eval 

func (ev *Evaler) Eval(name, text string, n *parse.Chunk, ports []*Port) error

Eval evaluates a chunk node n. The supplied name and text are used in diagnostic messages.

func (*Evaler) EvalInteractive 

func (ev *Evaler) EvalInteractive(text string, n *parse.Chunk) error

func (*Evaler) Search 

func (ev *Evaler) Search(exe string) (string, error)

Search tries to resolve an external command and return the full (possibly relative) path.

func (*Evaler) Source 

func (ev *Evaler) Source(fname string) error

Source evaluates the content of a file.

func (*Evaler) SourceText 

func (ev *Evaler) SourceText(src string) error

SourceText evaluates a chunk of elvish source.

type ExternalCmd 

type ExternalCmd struct {
	Name string
}

ExternalCmd is an external command.

func (ExternalCmd) Call 

func (e ExternalCmd) Call(ec *EvalCtx, argVals []Value)

Call calls an external command.

func (ExternalCmd) Kind 

func (ExternalCmd) Kind() string

func (ExternalCmd) Repr 

func (e ExternalCmd) Repr(int) string

type ExternalCmdExit 

type ExternalCmdExit struct {
	syscall.WaitStatus
	CmdName string
	Pid     int
}

ExternalCmdExit contains the exit status of external commands. If the command was stopped rather than terminated, the Pid field contains the pid of the process.

func FakeExternalCmdExit 

func FakeExternalCmdExit(name string, exit int, sig syscall.Signal) ExternalCmdExit

func (ExternalCmdExit) Error 

func (exit ExternalCmdExit) Error() string

type File 

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

func (File) Kind 

func (File) Kind() string

func (File) Repr 

func (f File) Repr(int) string

type Fn 

type Fn interface {
	Call(ec *EvalCtx, args []Value)
}

Fn is anything may be called on an evalCtx with a list of Value's.

type FnAsIndexer 

type FnAsIndexer struct {
	Fn
	// contains filtered or unexported fields
}

FnAsIndexer adapts a Fn to an Indexer.

func (FnAsIndexer) Index 

func (ci FnAsIndexer) Index(idx []Value) []Value

type FnValue 

type FnValue interface {
	Value
	Fn
}

type GlobPattern 

type GlobPattern glob.Pattern

GlobPattern is en ephemeral Value generated when evaluating tilde and wildcards.

func (GlobPattern) Index 

func (gp GlobPattern) Index(modifiers []Value) []Value

func (GlobPattern) Kind 

func (GlobPattern) Kind() string

func (GlobPattern) Repr 

func (gp GlobPattern) Repr(int) string

type HasKeyer 

type HasKeyer interface {
	HasKey(k Value) bool
}

type IndexOneer 

type IndexOneer interface {
	IndexOne(idx Value) Value
}

IndexOneer is anything that can be indexed by one Value and yields one Value.

type IndexOneerIndexer 

type IndexOneerIndexer struct {
	IndexOneer
}

IndexOneerIndexer adapts an IndexOneer to an Indexer by calling all the indicies on the IndexOner and collect the results.

func (IndexOneerIndexer) Index 

func (ioi IndexOneerIndexer) Index(vs []Value) []Value

type IndexSetter 

type IndexSetter interface {
	IndexOneer
	IndexSet(idx Value, v Value)
}

IndexSetter is a Value whose elements can be get as well as set.

type Indexer 

type Indexer interface {
	Index(idx []Value) []Value
}

Indexer is anything that can be indexed by Values and yields Values.

type IndexerAsFn 

type IndexerAsFn struct {
	Indexer
}

IndexerAsFn adapts an Indexer to a Fn.

func (IndexerAsFn) Call 

func (ic IndexerAsFn) Call(ec *EvalCtx, args []Value)

type Iterator 

type Iterator interface {
	Iterate(func(Value) bool)
}

Iterator is anything that can be iterated.

type IteratorValue 

type IteratorValue interface {
	Iterator
	Value
}

type Kinder 

type Kinder interface {
	Kind() string
}

Kinder is anything with kind string.

type LValuesOp 

type LValuesOp struct {
	Func       LValuesOpFunc
	Begin, End int
}

VariablesOp is an operation on an EvalCtx that produce Variable's.

func (LValuesOp) Exec 

func (op LValuesOp) Exec(ec *EvalCtx) []Variable

type LValuesOpFunc 

type LValuesOpFunc func(*EvalCtx) []Variable

type Lener 

type Lener interface {
	Len() int
}

Lener is anything with a length.

type List 

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

List is a list of Value's.

func NewList 

func NewList(vs ...Value) List

NewList creates a new List.

func (List) IndexOne 

func (l List) IndexOne(idx Value) Value

func (List) IndexSet 

func (l List) IndexSet(idx Value, v Value)

func (List) Iterate 

func (l List) Iterate(f func(Value) bool)

func (List) Kind 

func (List) Kind() string

func (List) Len 

func (l List) Len() int

func (List) MarshalJSON 

func (l List) MarshalJSON() ([]byte, error)

func (List) Repr 

func (l List) Repr(indent int) string

type ListLike 

type ListLike interface {
	Lener
	Iterator
	IndexOneer
}

type ListReprBuilder 

type ListReprBuilder struct {
	Indent int
	// contains filtered or unexported fields
}

ListReprBuilder helps to build Repr of list-like Values.

func (*ListReprBuilder) String 

func (b *ListReprBuilder) String() string

func (*ListReprBuilder) WriteElem 

func (b *ListReprBuilder) WriteElem(v string)

type Map 

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

Map is a map from string to Value.

func NewMap 

func NewMap(inner map[Value]Value) Map

NewMap creates a new Map.

func (Map) HasKey 

func (m Map) HasKey(k Value) bool

func (Map) IndexOne 

func (m Map) IndexOne(idx Value) Value

func (Map) IndexSet 

func (m Map) IndexSet(idx Value, v Value)

func (Map) Kind 

func (Map) Kind() string

func (Map) Len 

func (m Map) Len() int

func (Map) MarshalJSON 

func (m Map) MarshalJSON() ([]byte, error)

func (Map) Repr 

func (m Map) Repr(indent int) string

type MapLike 

type MapLike interface {
	Lener
	IndexOneer
	HasKeyer
}

type MapReprBuilder 

type MapReprBuilder struct {
	ListReprBuilder
}

MapReprBuilder helps building the Repr of a Map. It is also useful for implementing other Map-like values. The zero value of a MapReprBuilder is ready to use.

func (*MapReprBuilder) String 

func (b *MapReprBuilder) String() string

func (*MapReprBuilder) WritePair 

func (b *MapReprBuilder) WritePair(k, v string)

type MapStringString 

type MapStringString map[string]string

MapStringString implements MapLike for map[string]string.

func (MapStringString) HasKey 

func (m MapStringString) HasKey(idx Value) bool

func (MapStringString) IndexOne 

func (m MapStringString) IndexOne(idx Value) Value

func (MapStringString) IndexSet 

func (m MapStringString) IndexSet(idx Value, val Value)

func (MapStringString) Kind 

func (MapStringString) Kind() string

func (MapStringString) Len 

func (m MapStringString) Len() int

func (MapStringString) Repr 

func (m MapStringString) Repr(indent int) string

type MultiError 

type MultiError struct {
	Errors []Error
}

multiError is multiple errors packed into one. It is used for reporting errors of pipelines, in which multiple forms may error.

func (MultiError) Error 

func (me MultiError) Error() string

func (MultiError) Repr 

func (me MultiError) Repr(indent int) string

type Namespace 

type Namespace map[string]Variable

Namespace is a map from name to variables.

func Builtin 

func Builtin() Namespace

Builtin returns the builtin namespace.

type Op 

type Op struct {
	Func       OpFunc
	Begin, End int
}

Op is an operation on an EvalCtx.

func (Op) Exec 

func (op Op) Exec(ec *EvalCtx)

type OpFunc 

type OpFunc func(*EvalCtx)

type Pipe 

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

func (Pipe) Kind 

func (Pipe) Kind() string

func (Pipe) Repr 

func (p Pipe) Repr(int) string

type Port 

type Port struct {
	File      *os.File
	Chan      chan Value
	CloseFile bool
	CloseChan bool
}

Port conveys data stream. It always consists of a byte band and a channel band.

func (*Port) Close 

func (p *Port) Close()

Close closes a Port.

func (*Port) Fork 

func (p *Port) Fork() *Port

Fork returns a copy of a Port with the Close* flags unset.

type PwdVariable 

type PwdVariable struct{}

PwdVariable is a variable whose value always reflects the current working directory. Setting it changes the current working directory.

func (PwdVariable) Get 

func (PwdVariable) Get() Value

func (PwdVariable) Set 

func (PwdVariable) Set(v Value)

type Rat 

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

Rat is a rational number.

func ToRat 

func ToRat(v Value) (Rat, error)

ToRat converts a Value to rat. A str can be converted to a rat if it can be parsed. A rat is returned as-is. Other types of values cannot be converted.

func (Rat) Kind 

func (Rat) Kind() string

func (Rat) Repr 

func (r Rat) Repr(int) string

func (Rat) String 

func (r Rat) String() string

type Reprer 

type Reprer interface {
	// Repr returns a string that represents a Value. The string either be a
	// literal of that Value that is preferably deep-equal to it (like `[a b c]`
	// for a list), or a string enclosed in "<>" containing the kind and
	// identity of the Value(like `<fn 0xdeadcafe>`).
	//
	// If indent is at least 0, it should be pretty-printed with the current
	// indentation level of indent; the indent of the first line has already
	// been written and shall not be written in Repr. The returned string
	// should never contain a trailing newline.
	Repr(indent int) string
}

Reprer is anything with a Repr method.

type String 

type String string

String is just a string.

func (String) Call 

func (s String) Call(ec *EvalCtx, args []Value)

Call resolves a command name to either a Fn variable or external command and calls it.

func (String) Kind 

func (String) Kind() string

func (String) Len 

func (s String) Len() int

func (String) Repr 

func (s String) Repr(int) string

func (String) String 

func (s String) String() string

type Stringer 

type Stringer interface {
	String() string
}

Stringer is anything that can be converted to a string.

type Struct 

type Struct struct {
	FieldNames []string
	Fields     []Variable
}

Struct is like a Map with fixed keys.

func (*Struct) HasKey 

func (s *Struct) HasKey(k Value) bool

func (*Struct) IndexOne 

func (s *Struct) IndexOne(idx Value) Value

func (*Struct) IndexSet 

func (s *Struct) IndexSet(idx Value, v Value)

func (*Struct) Kind 

func (*Struct) Kind() string

func (*Struct) Len 

func (s *Struct) Len() int

func (*Struct) Repr 

func (s *Struct) Repr(indent int) string

type Value 

type Value interface {
	Kinder
	Reprer
}

Value is an elvish value.

func FromJSONInterface 

func FromJSONInterface(v interface{}) Value

FromJSONInterface converts a interface{} that results from json.Unmarshal to a Value.

type ValuesOp 

type ValuesOp struct {
	Func       ValuesOpFunc
	Begin, End int
}

ValuesOp is an operation on an EvalCtx that produce Value's.

func (ValuesOp) Exec 

func (op ValuesOp) Exec(ec *EvalCtx) []Value

type ValuesOpFunc 

type ValuesOpFunc func(*EvalCtx) []Value

type Variable 

type Variable interface {
	Set(v Value)
	Get() Value
}

Variable represents an elvish variable.

func NewPtrVariable 

func NewPtrVariable(v Value) Variable

func NewPtrVariableWithValidator 

func NewPtrVariableWithValidator(v Value, vld func(Value) error) Variable

func NewRoVariable 

func NewRoVariable(v Value) Variable

Notes

Bugs

  • We rely on the fact that os.Unsetenv always returns nil.

  • When evaluating closures, async access to global variables and ports can be problematic.

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