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Package ast

Overview

Package ast declares the types used to represent syntax trees for Go packages.

Index

Package files

ast.go commentmap.go filter.go import.go print.go resolve.go scope.go walk.go

func FileExportsSource

func FileExports(src *File) bool

FileExports trims the AST for a Go source file in place such that only exported nodes remain: all top-level identifiers which are not exported and their associated information (such as type, initial value, or function body) are removed. Non-exported fields and methods of exported types are stripped. The File.Comments list is not changed.

FileExports reports whether there are exported declarations.

func FilterDeclSource

func FilterDecl(decl Decl, f Filter) bool

FilterDecl trims the AST for a Go declaration in place by removing all names (including struct field and interface method names, but not from parameter lists) that don't pass through the filter f.

FilterDecl reports whether there are any declared names left after filtering.

func FilterFileSource

func FilterFile(src *File, f Filter) bool

FilterFile trims the AST for a Go file in place by removing all names from top-level declarations (including struct field and interface method names, but not from parameter lists) that don't pass through the filter f. If the declaration is empty afterwards, the declaration is removed from the AST. Import declarations are always removed. The File.Comments list is not changed.

FilterFile reports whether there are any top-level declarations left after filtering.

func FilterPackageSource

func FilterPackage(pkg *Package, f Filter) bool

FilterPackage trims the AST for a Go package in place by removing all names from top-level declarations (including struct field and interface method names, but not from parameter lists) that don't pass through the filter f. If the declaration is empty afterwards, the declaration is removed from the AST. The pkg.Files list is not changed, so that file names and top-level package comments don't get lost.

FilterPackage reports whether there are any top-level declarations left after filtering.

func FprintSource

func Fprint(w io.Writer, fset *token.FileSet, x interface{}, f FieldFilter) error

Fprint prints the (sub-)tree starting at AST node x to w. If fset != nil, position information is interpreted relative to that file set. Otherwise positions are printed as integer values (file set specific offsets).

A non-nil FieldFilter f may be provided to control the output: struct fields for which f(fieldname, fieldvalue) is true are printed; all others are filtered from the output. Unexported struct fields are never printed.

func InspectSource

func Inspect(node Node, f func(Node) bool)

Inspect traverses an AST in depth-first order: It starts by calling f(node); node must not be nil. If f returns true, Inspect invokes f recursively for each of the non-nil children of node, followed by a call of f(nil).

Example

This example demonstrates how to inspect the AST of a Go program.

package main

import (
	"fmt"
	"go/ast"
	"go/parser"
	"go/token"
)

func main() {
	// src is the input for which we want to inspect the AST.
	src := `
package p
const c = 1.0
var X = f(3.14)*2 + c
`

	// Create the AST by parsing src.
	fset := token.NewFileSet() // positions are relative to fset
	f, err := parser.ParseFile(fset, "src.go", src, 0)
	if err != nil {
		panic(err)
	}

	// Inspect the AST and print all identifiers and literals.
	ast.Inspect(f, func(n ast.Node) bool {
		var s string
		switch x := n.(type) {
		case *ast.BasicLit:
			s = x.Value
		case *ast.Ident:
			s = x.Name
		}
		if s != "" {
			fmt.Printf("%s:\t%s\n", fset.Position(n.Pos()), s)
		}
		return true
	})

}

func IsExportedSource

func IsExported(name string) bool

IsExported reports whether name is an exported Go symbol (that is, whether it begins with an upper-case letter).

func NotNilFilterSource

func NotNilFilter(_ string, v reflect.Value) bool

NotNilFilter returns true for field values that are not nil; it returns false otherwise.

func PackageExportsSource

func PackageExports(pkg *Package) bool

PackageExports trims the AST for a Go package in place such that only exported nodes remain. The pkg.Files list is not changed, so that file names and top-level package comments don't get lost.

PackageExports reports whether there are exported declarations; it returns false otherwise.

func PrintSource

func Print(fset *token.FileSet, x interface{}) error

Print prints x to standard output, skipping nil fields. Print(fset, x) is the same as Fprint(os.Stdout, fset, x, NotNilFilter).

Example

This example shows what an AST looks like when printed for debugging.

package main

import (
	"go/ast"
	"go/parser"
	"go/token"
)

func main() {
	// src is the input for which we want to print the AST.
	src := `
package main
func main() {
	println("Hello, World!")
}
`

	// Create the AST by parsing src.
	fset := token.NewFileSet() // positions are relative to fset
	f, err := parser.ParseFile(fset, "", src, 0)
	if err != nil {
		panic(err)
	}

	// Print the AST.
	ast.Print(fset, f)

}

func SortImportsSource

func SortImports(fset *token.FileSet, f *File)

SortImports sorts runs of consecutive import lines in import blocks in f. It also removes duplicate imports when it is possible to do so without data loss.

func WalkSource

func Walk(v Visitor, node Node)

Walk traverses an AST in depth-first order: It starts by calling v.Visit(node); node must not be nil. If the visitor w returned by v.Visit(node) is not nil, Walk is invoked recursively with visitor w for each of the non-nil children of node, followed by a call of w.Visit(nil).

type ArrayTypeSource

An ArrayType node represents an array or slice type.

type ArrayType struct {
        Lbrack token.Pos // position of "["
        Len    Expr      // Ellipsis node for [...]T array types, nil for slice types
        Elt    Expr      // element type
}

func (*ArrayType) EndSource

func (x *ArrayType) End() token.Pos

func (*ArrayType) PosSource

func (x *ArrayType) Pos() token.Pos

type AssignStmtSource

An AssignStmt node represents an assignment or a short variable declaration.

type AssignStmt struct {
        Lhs    []Expr
        TokPos token.Pos   // position of Tok
        Tok    token.Token // assignment token, DEFINE
        Rhs    []Expr
}

func (*AssignStmt) EndSource

func (s *AssignStmt) End() token.Pos

func (*AssignStmt) PosSource

func (s *AssignStmt) Pos() token.Pos

type BadDeclSource

A BadDecl node is a placeholder for declarations containing syntax errors for which no correct declaration nodes can be created.

type BadDecl struct {
        From, To token.Pos // position range of bad declaration
}

func (*BadDecl) EndSource

func (d *BadDecl) End() token.Pos

func (*BadDecl) PosSource

func (d *BadDecl) Pos() token.Pos

type BadExprSource

A BadExpr node is a placeholder for expressions containing syntax errors for which no correct expression nodes can be created.

type BadExpr struct {
        From, To token.Pos // position range of bad expression
}

func (*BadExpr) EndSource

func (x *BadExpr) End() token.Pos

func (*BadExpr) PosSource

func (x *BadExpr) Pos() token.Pos

type BadStmtSource

A BadStmt node is a placeholder for statements containing syntax errors for which no correct statement nodes can be created.

type BadStmt struct {
        From, To token.Pos // position range of bad statement
}

func (*BadStmt) EndSource

func (s *BadStmt) End() token.Pos

func (*BadStmt) PosSource

func (s *BadStmt) Pos() token.Pos

type BasicLitSource

A BasicLit node represents a literal of basic type.

type BasicLit struct {
        ValuePos token.Pos   // literal position
        Kind     token.Token // token.INT, token.FLOAT, token.IMAG, token.CHAR, or token.STRING
        Value    string      // literal string; e.g. 42, 0x7f, 3.14, 1e-9, 2.4i, 'a', '\x7f', "foo" or `\m\n\o`
}

func (*BasicLit) EndSource

func (x *BasicLit) End() token.Pos

func (*BasicLit) PosSource

func (x *BasicLit) Pos() token.Pos

type BinaryExprSource

A BinaryExpr node represents a binary expression.

type BinaryExpr struct {
        X     Expr        // left operand
        OpPos token.Pos   // position of Op
        Op    token.Token // operator
        Y     Expr        // right operand
}

func (*BinaryExpr) EndSource

func (x *BinaryExpr) End() token.Pos

func (*BinaryExpr) PosSource

func (x *BinaryExpr) Pos() token.Pos

type BlockStmtSource

A BlockStmt node represents a braced statement list.

type BlockStmt struct {
        Lbrace token.Pos // position of "{"
        List   []Stmt
        Rbrace token.Pos // position of "}"
}

func (*BlockStmt) EndSource

func (s *BlockStmt) End() token.Pos

func (*BlockStmt) PosSource

func (s *BlockStmt) Pos() token.Pos

type BranchStmtSource

A BranchStmt node represents a break, continue, goto, or fallthrough statement.

type BranchStmt struct {
        TokPos token.Pos   // position of Tok
        Tok    token.Token // keyword token (BREAK, CONTINUE, GOTO, FALLTHROUGH)
        Label  *Ident      // label name; or nil
}

func (*BranchStmt) EndSource

func (s *BranchStmt) End() token.Pos

func (*BranchStmt) PosSource

func (s *BranchStmt) Pos() token.Pos

type CallExprSource

A CallExpr node represents an expression followed by an argument list.

type CallExpr struct {
        Fun      Expr      // function expression
        Lparen   token.Pos // position of "("
        Args     []Expr    // function arguments; or nil
        Ellipsis token.Pos // position of "..." (token.NoPos if there is no "...")
        Rparen   token.Pos // position of ")"
}

func (*CallExpr) EndSource

func (x *CallExpr) End() token.Pos

func (*CallExpr) PosSource

func (x *CallExpr) Pos() token.Pos

type CaseClauseSource

A CaseClause represents a case of an expression or type switch statement.

type CaseClause struct {
        Case  token.Pos // position of "case" or "default" keyword
        List  []Expr    // list of expressions or types; nil means default case
        Colon token.Pos // position of ":"
        Body  []Stmt    // statement list; or nil
}

func (*CaseClause) EndSource

func (s *CaseClause) End() token.Pos

func (*CaseClause) PosSource

func (s *CaseClause) Pos() token.Pos

type ChanDirSource

The direction of a channel type is indicated by one of the following constants.

type ChanDir int
const (
        SEND ChanDir = 1 << iota
        RECV
)

type ChanTypeSource

A ChanType node represents a channel type.

type ChanType struct {
        Begin token.Pos // position of "chan" keyword or "<-" (whichever comes first)
        Arrow token.Pos // position of "<-" (token.NoPos if there is no "<-")
        Dir   ChanDir   // channel direction
        Value Expr      // value type
}

func (*ChanType) EndSource

func (x *ChanType) End() token.Pos

func (*ChanType) PosSource

func (x *ChanType) Pos() token.Pos

type CommClauseSource

A CommClause node represents a case of a select statement.

type CommClause struct {
        Case  token.Pos // position of "case" or "default" keyword
        Comm  Stmt      // send or receive statement; nil means default case
        Colon token.Pos // position of ":"
        Body  []Stmt    // statement list; or nil
}

func (*CommClause) EndSource

func (s *CommClause) End() token.Pos

func (*CommClause) PosSource

func (s *CommClause) Pos() token.Pos

type CommentSource

A Comment node represents a single //-style or /*-style comment.

type Comment struct {
        Slash token.Pos // position of "/" starting the comment
        Text  string    // comment text (excluding '\n' for //-style comments)
}

func (*Comment) EndSource

func (c *Comment) End() token.Pos

func (*Comment) PosSource

func (c *Comment) Pos() token.Pos

type CommentGroupSource

A CommentGroup represents a sequence of comments with no other tokens and no empty lines between.

type CommentGroup struct {
        List []*Comment // len(List) > 0
}

func (*CommentGroup) EndSource

func (g *CommentGroup) End() token.Pos

func (*CommentGroup) PosSource

func (g *CommentGroup) Pos() token.Pos

func (*CommentGroup) TextSource

func (g *CommentGroup) Text() string

Text returns the text of the comment. Comment markers (//, /*, and */), the first space of a line comment, and leading and trailing empty lines are removed. Multiple empty lines are reduced to one, and trailing space on lines is trimmed. Unless the result is empty, it is newline-terminated.

type CommentMapSource

A CommentMap maps an AST node to a list of comment groups associated with it. See NewCommentMap for a description of the association.

type CommentMap map[Node][]*CommentGroup

Example

This example illustrates how to remove a variable declaration in a Go program while maintaining correct comment association using an ast.CommentMap.

Code:

// src is the input for which we create the AST that we
// are going to manipulate.
src := `
// This is the package comment.
package main

// This comment is associated with the hello constant.
const hello = "Hello, World!" // line comment 1

// This comment is associated with the foo variable.
var foo = hello // line comment 2 

// This comment is associated with the main function.
func main() {
        fmt.Println(hello) // line comment 3
}
`

// Create the AST by parsing src.
fset := token.NewFileSet() // positions are relative to fset
f, err := parser.ParseFile(fset, "src.go", src, parser.ParseComments)
if err != nil {
        panic(err)
}

// Create an ast.CommentMap from the ast.File's comments.
// This helps keeping the association between comments
// and AST nodes.
cmap := ast.NewCommentMap(fset, f, f.Comments)

// Remove the first variable declaration from the list of declarations.
f.Decls = removeFirstVarDecl(f.Decls)

// Use the comment map to filter comments that don't belong anymore
// (the comments associated with the variable declaration), and create
// the new comments list.
f.Comments = cmap.Filter(f).Comments()

// Print the modified AST.
var buf bytes.Buffer
if err := format.Node(&buf, fset, f); err != nil {
        panic(err)
}
fmt.Printf("%s", buf.Bytes())

Output:

// This is the package comment.
package main

// This comment is associated with the hello constant.
const hello = "Hello, World!" // line comment 1

// This comment is associated with the main function.
func main() {
	fmt.Println(hello) // line comment 3
}

func NewCommentMapSource

func NewCommentMap(fset *token.FileSet, node Node, comments []*CommentGroup) CommentMap

NewCommentMap creates a new comment map by associating comment groups of the comments list with the nodes of the AST specified by node.

A comment group g is associated with a node n if:

- g starts on the same line as n ends
- g starts on the line immediately following n, and there is
  at least one empty line after g and before the next node
- g starts before n and is not associated to the node before n
  via the previous rules

NewCommentMap tries to associate a comment group to the "largest" node possible: For instance, if the comment is a line comment trailing an assignment, the comment is associated with the entire assignment rather than just the last operand in the assignment.

func (CommentMap) CommentsSource

func (cmap CommentMap) Comments() []*CommentGroup

Comments returns the list of comment groups in the comment map. The result is sorted in source order.

func (CommentMap) FilterSource

func (cmap CommentMap) Filter(node Node) CommentMap

Filter returns a new comment map consisting of only those entries of cmap for which a corresponding node exists in the AST specified by node.

func (CommentMap) StringSource

func (cmap CommentMap) String() string

func (CommentMap) UpdateSource

func (cmap CommentMap) Update(old, new Node) Node

Update replaces an old node in the comment map with the new node and returns the new node. Comments that were associated with the old node are associated with the new node.

type CompositeLitSource

A CompositeLit node represents a composite literal.

type CompositeLit struct {
        Type   Expr      // literal type; or nil
        Lbrace token.Pos // position of "{"
        Elts   []Expr    // list of composite elements; or nil
        Rbrace token.Pos // position of "}"
}

func (*CompositeLit) EndSource

func (x *CompositeLit) End() token.Pos

func (*CompositeLit) PosSource

func (x *CompositeLit) Pos() token.Pos

type DeclSource

All declaration nodes implement the Decl interface.

type Decl interface {
        Node
        // contains filtered or unexported methods
}

type DeclStmtSource

A DeclStmt node represents a declaration in a statement list.

type DeclStmt struct {
        Decl Decl // *GenDecl with CONST, TYPE, or VAR token
}

func (*DeclStmt) EndSource

func (s *DeclStmt) End() token.Pos

func (*DeclStmt) PosSource

func (s *DeclStmt) Pos() token.Pos

type DeferStmtSource

A DeferStmt node represents a defer statement.

type DeferStmt struct {
        Defer token.Pos // position of "defer" keyword
        Call  *CallExpr
}

func (*DeferStmt) EndSource

func (s *DeferStmt) End() token.Pos

func (*DeferStmt) PosSource

func (s *DeferStmt) Pos() token.Pos

type EllipsisSource

An Ellipsis node stands for the "..." type in a parameter list or the "..." length in an array type.

type Ellipsis struct {
        Ellipsis token.Pos // position of "..."
        Elt      Expr      // ellipsis element type (parameter lists only); or nil
}

func (*Ellipsis) EndSource

func (x *Ellipsis) End() token.Pos

func (*Ellipsis) PosSource

func (x *Ellipsis) Pos() token.Pos

type EmptyStmtSource

An EmptyStmt node represents an empty statement. The "position" of the empty statement is the position of the immediately following (explicit or implicit) semicolon.

type EmptyStmt struct {
        Semicolon token.Pos // position of following ";"
        Implicit  bool      // if set, ";" was omitted in the source
}

func (*EmptyStmt) EndSource

func (s *EmptyStmt) End() token.Pos

func (*EmptyStmt) PosSource

func (s *EmptyStmt) Pos() token.Pos

type ExprSource

All expression nodes implement the Expr interface.

type Expr interface {
        Node
        // contains filtered or unexported methods
}

type ExprStmtSource

An ExprStmt node represents a (stand-alone) expression in a statement list.

type ExprStmt struct {
        X Expr // expression
}

func (*ExprStmt) EndSource

func (s *ExprStmt) End() token.Pos

func (*ExprStmt) PosSource

func (s *ExprStmt) Pos() token.Pos

type FieldSource

A Field represents a Field declaration list in a struct type, a method list in an interface type, or a parameter/result declaration in a signature.

type Field struct {
        Doc     *CommentGroup // associated documentation; or nil
        Names   []*Ident      // field/method/parameter names; or nil if anonymous field
        Type    Expr          // field/method/parameter type
        Tag     *BasicLit     // field tag; or nil
        Comment *CommentGroup // line comments; or nil
}

func (*Field) EndSource

func (f *Field) End() token.Pos

func (*Field) PosSource

func (f *Field) Pos() token.Pos

type FieldFilterSource

A FieldFilter may be provided to Fprint to control the output.

type FieldFilter func(name string, value reflect.Value) bool

type FieldListSource

A FieldList represents a list of Fields, enclosed by parentheses or braces.

type FieldList struct {
        Opening token.Pos // position of opening parenthesis/brace, if any
        List    []*Field  // field list; or nil
        Closing token.Pos // position of closing parenthesis/brace, if any
}

func (*FieldList) EndSource

func (f *FieldList) End() token.Pos

func (*FieldList) NumFieldsSource

func (f *FieldList) NumFields() int

NumFields returns the number of (named and anonymous fields) in a FieldList.

func (*FieldList) PosSource

func (f *FieldList) Pos() token.Pos

type FileSource

A File node represents a Go source file.

The Comments list contains all comments in the source file in order of appearance, including the comments that are pointed to from other nodes via Doc and Comment fields.

type File struct {
        Doc        *CommentGroup   // associated documentation; or nil
        Package    token.Pos       // position of "package" keyword
        Name       *Ident          // package name
        Decls      []Decl          // top-level declarations; or nil
        Scope      *Scope          // package scope (this file only)
        Imports    []*ImportSpec   // imports in this file
        Unresolved []*Ident        // unresolved identifiers in this file
        Comments   []*CommentGroup // list of all comments in the source file
}

func MergePackageFilesSource

func MergePackageFiles(pkg *Package, mode MergeMode) *File

MergePackageFiles creates a file AST by merging the ASTs of the files belonging to a package. The mode flags control merging behavior.

func (*File) EndSource

func (f *File) End() token.Pos

func (*File) PosSource

func (f *File) Pos() token.Pos

type FilterSource

type Filter func(string) bool

type ForStmtSource

A ForStmt represents a for statement.

type ForStmt struct {
        For  token.Pos // position of "for" keyword
        Init Stmt      // initialization statement; or nil
        Cond Expr      // condition; or nil
        Post Stmt      // post iteration statement; or nil
        Body *BlockStmt
}

func (*ForStmt) EndSource

func (s *ForStmt) End() token.Pos

func (*ForStmt) PosSource

func (s *ForStmt) Pos() token.Pos

type FuncDeclSource

A FuncDecl node represents a function declaration.

type FuncDecl struct {
        Doc  *CommentGroup // associated documentation; or nil
        Recv *FieldList    // receiver (methods); or nil (functions)
        Name *Ident        // function/method name
        Type *FuncType     // function signature: parameters, results, and position of "func" keyword
        Body *BlockStmt    // function body; or nil (forward declaration)
}

func (*FuncDecl) EndSource

func (d *FuncDecl) End() token.Pos

func (*FuncDecl) PosSource

func (d *FuncDecl) Pos() token.Pos

type FuncLitSource

A FuncLit node represents a function literal.

type FuncLit struct {
        Type *FuncType  // function type
        Body *BlockStmt // function body
}

func (*FuncLit) EndSource

func (x *FuncLit) End() token.Pos

func (*FuncLit) PosSource

func (x *FuncLit) Pos() token.Pos

type FuncTypeSource

A FuncType node represents a function type.

type FuncType struct {
        Func    token.Pos  // position of "func" keyword (token.NoPos if there is no "func")
        Params  *FieldList // (incoming) parameters; non-nil
        Results *FieldList // (outgoing) results; or nil
}

func (*FuncType) EndSource

func (x *FuncType) End() token.Pos

func (*FuncType) PosSource

func (x *FuncType) Pos() token.Pos

type GenDeclSource

A GenDecl node (generic declaration node) represents an import, constant, type or variable declaration. A valid Lparen position (Lparen.IsValid()) indicates a parenthesized declaration.

Relationship between Tok value and Specs element type:

token.IMPORT  *ImportSpec
token.CONST   *ValueSpec
token.TYPE    *TypeSpec
token.VAR     *ValueSpec
type GenDecl struct {
        Doc    *CommentGroup // associated documentation; or nil
        TokPos token.Pos     // position of Tok
        Tok    token.Token   // IMPORT, CONST, TYPE, VAR
        Lparen token.Pos     // position of '(', if any
        Specs  []Spec
        Rparen token.Pos // position of ')', if any
}

func (*GenDecl) EndSource

func (d *GenDecl) End() token.Pos

func (*GenDecl) PosSource

func (d *GenDecl) Pos() token.Pos

type GoStmtSource

A GoStmt node represents a go statement.

type GoStmt struct {
        Go   token.Pos // position of "go" keyword
        Call *CallExpr
}

func (*GoStmt) EndSource

func (s *GoStmt) End() token.Pos

func (*GoStmt) PosSource

func (s *GoStmt) Pos() token.Pos

type IdentSource

An Ident node represents an identifier.

type Ident struct {
        NamePos token.Pos // identifier position
        Name    string    // identifier name
        Obj     *Object   // denoted object; or nil
}

func NewIdentSource

func NewIdent(name string) *Ident

NewIdent creates a new Ident without position. Useful for ASTs generated by code other than the Go parser.

func (*Ident) EndSource

func (x *Ident) End() token.Pos

func (*Ident) IsExportedSource

func (id *Ident) IsExported() bool

IsExported reports whether id is an exported Go symbol (that is, whether it begins with an uppercase letter).

func (*Ident) PosSource

func (x *Ident) Pos() token.Pos

func (*Ident) StringSource

func (id *Ident) String() string

type IfStmtSource

An IfStmt node represents an if statement.

type IfStmt struct {
        If   token.Pos // position of "if" keyword
        Init Stmt      // initialization statement; or nil
        Cond Expr      // condition
        Body *BlockStmt
        Else Stmt // else branch; or nil
}

func (*IfStmt) EndSource

func (s *IfStmt) End() token.Pos

func (*IfStmt) PosSource

func (s *IfStmt) Pos() token.Pos

type ImportSpecSource

An ImportSpec node represents a single package import.

type ImportSpec struct {
        Doc     *CommentGroup // associated documentation; or nil
        Name    *Ident        // local package name (including "."); or nil
        Path    *BasicLit     // import path
        Comment *CommentGroup // line comments; or nil
        EndPos  token.Pos     // end of spec (overrides Path.Pos if nonzero)
}

func (*ImportSpec) EndSource

func (s *ImportSpec) End() token.Pos

func (*ImportSpec) PosSource

func (s *ImportSpec) Pos() token.Pos

type ImporterSource

An Importer resolves import paths to package Objects. The imports map records the packages already imported, indexed by package id (canonical import path). An Importer must determine the canonical import path and check the map to see if it is already present in the imports map. If so, the Importer can return the map entry. Otherwise, the Importer should load the package data for the given path into a new *Object (pkg), record pkg in the imports map, and then return pkg.

type Importer func(imports map[string]*Object, path string) (pkg *Object, err error)

type IncDecStmtSource

An IncDecStmt node represents an increment or decrement statement.

type IncDecStmt struct {
        X      Expr
        TokPos token.Pos   // position of Tok
        Tok    token.Token // INC or DEC
}

func (*IncDecStmt) EndSource

func (s *IncDecStmt) End() token.Pos

func (*IncDecStmt) PosSource

func (s *IncDecStmt) Pos() token.Pos

type IndexExprSource

An IndexExpr node represents an expression followed by an index.

type IndexExpr struct {
        X      Expr      // expression
        Lbrack token.Pos // position of "["
        Index  Expr      // index expression
        Rbrack token.Pos // position of "]"
}

func (*IndexExpr) EndSource

func (x *IndexExpr) End() token.Pos

func (*IndexExpr) PosSource

func (x *IndexExpr) Pos() token.Pos

type InterfaceTypeSource

An InterfaceType node represents an interface type.

type InterfaceType struct {
        Interface  token.Pos  // position of "interface" keyword
        Methods    *FieldList // list of methods
        Incomplete bool       // true if (source) methods are missing in the Methods list
}

func (*InterfaceType) EndSource

func (x *InterfaceType) End() token.Pos

func (*InterfaceType) PosSource

func (x *InterfaceType) Pos() token.Pos

type KeyValueExprSource

A KeyValueExpr node represents (key : value) pairs in composite literals.

type KeyValueExpr struct {
        Key   Expr
        Colon token.Pos // position of ":"
        Value Expr
}

func (*KeyValueExpr) EndSource

func (x *KeyValueExpr) End() token.Pos

func (*KeyValueExpr) PosSource

func (x *KeyValueExpr) Pos() token.Pos

type LabeledStmtSource

A LabeledStmt node represents a labeled statement.

type LabeledStmt struct {
        Label *Ident
        Colon token.Pos // position of ":"
        Stmt  Stmt
}

func (*LabeledStmt) EndSource

func (s *LabeledStmt) End() token.Pos

func (*LabeledStmt) PosSource

func (s *LabeledStmt) Pos() token.Pos

type MapTypeSource

A MapType node represents a map type.

type MapType struct {
        Map   token.Pos // position of "map" keyword
        Key   Expr
        Value Expr
}

func (*MapType) EndSource

func (x *MapType) End() token.Pos

func (*MapType) PosSource

func (x *MapType) Pos() token.Pos

type MergeModeSource

The MergeMode flags control the behavior of MergePackageFiles.

type MergeMode uint
const (
        // If set, duplicate function declarations are excluded.
        FilterFuncDuplicates MergeMode = 1 << iota
        // If set, comments that are not associated with a specific
        // AST node (as Doc or Comment) are excluded.
        FilterUnassociatedComments
        // If set, duplicate import declarations are excluded.
        FilterImportDuplicates
)

type NodeSource

All node types implement the Node interface.

type Node interface {
        Pos() token.Pos // position of first character belonging to the node
        End() token.Pos // position of first character immediately after the node
}

type ObjKindSource

ObjKind describes what an object represents.

type ObjKind int

The list of possible Object kinds.

const (
        Bad ObjKind = iota // for error handling
        Pkg                // package
        Con                // constant
        Typ                // type
        Var                // variable
        Fun                // function or method
        Lbl                // label
)

func (ObjKind) StringSource

func (kind ObjKind) String() string

type ObjectSource

An Object describes a named language entity such as a package, constant, type, variable, function (incl. methods), or label.

The Data fields contains object-specific data:

Kind    Data type         Data value
Pkg     *Scope            package scope
Con     int               iota for the respective declaration
type Object struct {
        Kind ObjKind
        Name string      // declared name
        Decl interface{} // corresponding Field, XxxSpec, FuncDecl, LabeledStmt, AssignStmt, Scope; or nil
        Data interface{} // object-specific data; or nil
        Type interface{} // placeholder for type information; may be nil
}

func NewObjSource

func NewObj(kind ObjKind, name string) *Object

NewObj creates a new object of a given kind and name.

func (*Object) PosSource

func (obj *Object) Pos() token.Pos

Pos computes the source position of the declaration of an object name. The result may be an invalid position if it cannot be computed (obj.Decl may be nil or not correct).

type PackageSource

A Package node represents a set of source files collectively building a Go package.

type Package struct {
        Name    string             // package name
        Scope   *Scope             // package scope across all files
        Imports map[string]*Object // map of package id -> package object
        Files   map[string]*File   // Go source files by filename
}

func NewPackageSource

func NewPackage(fset *token.FileSet, files map[string]*File, importer Importer, universe *Scope) (*Package, error)

NewPackage creates a new Package node from a set of File nodes. It resolves unresolved identifiers across files and updates each file's Unresolved list accordingly. If a non-nil importer and universe scope are provided, they are used to resolve identifiers not declared in any of the package files. Any remaining unresolved identifiers are reported as undeclared. If the files belong to different packages, one package name is selected and files with different package names are reported and then ignored. The result is a package node and a scanner.ErrorList if there were errors.

func (*Package) EndSource

func (p *Package) End() token.Pos

func (*Package) PosSource

func (p *Package) Pos() token.Pos

type ParenExprSource

A ParenExpr node represents a parenthesized expression.

type ParenExpr struct {
        Lparen token.Pos // position of "("
        X      Expr      // parenthesized expression
        Rparen token.Pos // position of ")"
}

func (*ParenExpr) EndSource

func (x *ParenExpr) End() token.Pos

func (*ParenExpr) PosSource

func (x *ParenExpr) Pos() token.Pos

type RangeStmtSource

A RangeStmt represents a for statement with a range clause.

type RangeStmt struct {
        For        token.Pos   // position of "for" keyword
        Key, Value Expr        // Key, Value may be nil
        TokPos     token.Pos   // position of Tok; invalid if Key == nil
        Tok        token.Token // ILLEGAL if Key == nil, ASSIGN, DEFINE
        X          Expr        // value to range over
        Body       *BlockStmt
}

func (*RangeStmt) EndSource

func (s *RangeStmt) End() token.Pos

func (*RangeStmt) PosSource

func (s *RangeStmt) Pos() token.Pos

type ReturnStmtSource

A ReturnStmt node represents a return statement.

type ReturnStmt struct {
        Return  token.Pos // position of "return" keyword
        Results []Expr    // result expressions; or nil
}

func (*ReturnStmt) EndSource

func (s *ReturnStmt) End() token.Pos

func (*ReturnStmt) PosSource

func (s *ReturnStmt) Pos() token.Pos

type ScopeSource

A Scope maintains the set of named language entities declared in the scope and a link to the immediately surrounding (outer) scope.

type Scope struct {
        Outer   *Scope
        Objects map[string]*Object
}

func NewScopeSource

func NewScope(outer *Scope) *Scope

NewScope creates a new scope nested in the outer scope.

func (*Scope) InsertSource

func (s *Scope) Insert(obj *Object) (alt *Object)

Insert attempts to insert a named object obj into the scope s. If the scope already contains an object alt with the same name, Insert leaves the scope unchanged and returns alt. Otherwise it inserts obj and returns nil.

func (*Scope) LookupSource

func (s *Scope) Lookup(name string) *Object

Lookup returns the object with the given name if it is found in scope s, otherwise it returns nil. Outer scopes are ignored.

func (*Scope) StringSource

func (s *Scope) String() string

Debugging support

type SelectStmtSource

An SelectStmt node represents a select statement.

type SelectStmt struct {
        Select token.Pos  // position of "select" keyword
        Body   *BlockStmt // CommClauses only
}

func (*SelectStmt) EndSource

func (s *SelectStmt) End() token.Pos

func (*SelectStmt) PosSource

func (s *SelectStmt) Pos() token.Pos

type SelectorExprSource

A SelectorExpr node represents an expression followed by a selector.

type SelectorExpr struct {
        X   Expr   // expression
        Sel *Ident // field selector
}

func (*SelectorExpr) EndSource

func (x *SelectorExpr) End() token.Pos

func (*SelectorExpr) PosSource

func (x *SelectorExpr) Pos() token.Pos

type SendStmtSource

A SendStmt node represents a send statement.

type SendStmt struct {
        Chan  Expr
        Arrow token.Pos // position of "<-"
        Value Expr
}

func (*SendStmt) EndSource

func (s *SendStmt) End() token.Pos

func (*SendStmt) PosSource

func (s *SendStmt) Pos() token.Pos

type SliceExprSource

An SliceExpr node represents an expression followed by slice indices.

type SliceExpr struct {
        X      Expr      // expression
        Lbrack token.Pos // position of "["
        Low    Expr      // begin of slice range; or nil
        High   Expr      // end of slice range; or nil
        Max    Expr      // maximum capacity of slice; or nil
        Slice3 bool      // true if 3-index slice (2 colons present)
        Rbrack token.Pos // position of "]"
}

func (*SliceExpr) EndSource

func (x *SliceExpr) End() token.Pos

func (*SliceExpr) PosSource

func (x *SliceExpr) Pos() token.Pos

type SpecSource

The Spec type stands for any of *ImportSpec, *ValueSpec, and *TypeSpec.

type Spec interface {
        Node
        // contains filtered or unexported methods
}

type StarExprSource

A StarExpr node represents an expression of the form "*" Expression. Semantically it could be a unary "*" expression, or a pointer type.

type StarExpr struct {
        Star token.Pos // position of "*"
        X    Expr      // operand
}

func (*StarExpr) EndSource

func (x *StarExpr) End() token.Pos

func (*StarExpr) PosSource

func (x *StarExpr) Pos() token.Pos

type StmtSource

All statement nodes implement the Stmt interface.

type Stmt interface {
        Node
        // contains filtered or unexported methods
}

type StructTypeSource

A StructType node represents a struct type.

type StructType struct {
        Struct     token.Pos  // position of "struct" keyword
        Fields     *FieldList // list of field declarations
        Incomplete bool       // true if (source) fields are missing in the Fields list
}

func (*StructType) EndSource

func (x *StructType) End() token.Pos

func (*StructType) PosSource

func (x *StructType) Pos() token.Pos

type SwitchStmtSource

A SwitchStmt node represents an expression switch statement.

type SwitchStmt struct {
        Switch token.Pos  // position of "switch" keyword
        Init   Stmt       // initialization statement; or nil
        Tag    Expr       // tag expression; or nil
        Body   *BlockStmt // CaseClauses only
}

func (*SwitchStmt) EndSource

func (s *SwitchStmt) End() token.Pos

func (*SwitchStmt) PosSource

func (s *SwitchStmt) Pos() token.Pos

type TypeAssertExprSource

A TypeAssertExpr node represents an expression followed by a type assertion.

type TypeAssertExpr struct {
        X      Expr      // expression
        Lparen token.Pos // position of "("
        Type   Expr      // asserted type; nil means type switch X.(type)
        Rparen token.Pos // position of ")"
}

func (*TypeAssertExpr) EndSource

func (x *TypeAssertExpr) End() token.Pos

func (*TypeAssertExpr) PosSource

func (x *TypeAssertExpr) Pos() token.Pos

type TypeSpecSource

A TypeSpec node represents a type declaration (TypeSpec production).

type TypeSpec struct {
        Doc     *CommentGroup // associated documentation; or nil
        Name    *Ident        // type name
        Type    Expr          // *Ident, *ParenExpr, *SelectorExpr, *StarExpr, or any of the *XxxTypes
        Comment *CommentGroup // line comments; or nil
}

func (*TypeSpec) EndSource

func (s *TypeSpec) End() token.Pos

func (*TypeSpec) PosSource

func (s *TypeSpec) Pos() token.Pos

type TypeSwitchStmtSource

An TypeSwitchStmt node represents a type switch statement.

type TypeSwitchStmt struct {
        Switch token.Pos  // position of "switch" keyword
        Init   Stmt       // initialization statement; or nil
        Assign Stmt       // x := y.(type) or y.(type)
        Body   *BlockStmt // CaseClauses only
}

func (*TypeSwitchStmt) EndSource

func (s *TypeSwitchStmt) End() token.Pos

func (*TypeSwitchStmt) PosSource

func (s *TypeSwitchStmt) Pos() token.Pos

type UnaryExprSource

A UnaryExpr node represents a unary expression. Unary "*" expressions are represented via StarExpr nodes.

type UnaryExpr struct {
        OpPos token.Pos   // position of Op
        Op    token.Token // operator
        X     Expr        // operand
}

func (*UnaryExpr) EndSource

func (x *UnaryExpr) End() token.Pos

func (*UnaryExpr) PosSource

func (x *UnaryExpr) Pos() token.Pos

type ValueSpecSource

A ValueSpec node represents a constant or variable declaration (ConstSpec or VarSpec production).

type ValueSpec struct {
        Doc     *CommentGroup // associated documentation; or nil
        Names   []*Ident      // value names (len(Names) > 0)
        Type    Expr          // value type; or nil
        Values  []Expr        // initial values; or nil
        Comment *CommentGroup // line comments; or nil
}

func (*ValueSpec) EndSource

func (s *ValueSpec) End() token.Pos

func (*ValueSpec) PosSource

func (s *ValueSpec) Pos() token.Pos

type VisitorSource

A Visitor's Visit method is invoked for each node encountered by Walk. If the result visitor w is not nil, Walk visits each of the children of node with the visitor w, followed by a call of w.Visit(nil).

type Visitor interface {
        Visit(node Node) (w Visitor)
}

© Google, Inc.
Licensed under the Creative Commons Attribution License 3.0.
https://golang.org/pkg/go/ast/