Documentation ¶
Overview ¶
Package ast declares the types used to represent syntax trees for Go packages.
Index ¶
- func FileExports(src *File) bool
- func FilterDecl(decl Decl, f Filter) bool
- func FilterFile(src *File, f Filter) bool
- func FilterPackage(pkg *Package, f Filter) bool
- func Fprint(w io.Writer, fset *token.FileSet, x interface{}, f FieldFilter) (n int, err os.Error)
- func Inspect(node Node, f func(Node) bool)
- func IsExported(name string) bool
- func NotNilFilter(_ string, v reflect.Value) bool
- func PackageExports(pkg *Package) bool
- func Print(fset *token.FileSet, x interface{}) (int, os.Error)
- func Walk(v Visitor, node Node)
- type ArrayType
- type AssignStmt
- type BadDecl
- type BadExpr
- type BadStmt
- type BasicLit
- type BinaryExpr
- type BlockStmt
- type BranchStmt
- type CallExpr
- type CaseClause
- type ChanDir
- type ChanType
- type CommClause
- type Comment
- type CommentGroup
- type CompositeLit
- type Decl
- type DeclStmt
- type DeferStmt
- type Ellipsis
- type EmptyStmt
- type Expr
- type ExprStmt
- type Field
- type FieldFilter
- type FieldList
- type File
- type Filter
- type ForStmt
- type FuncDecl
- type FuncLit
- type FuncType
- type GenDecl
- type GoStmt
- type Ident
- type IfStmt
- type ImportSpec
- type Importer
- type IncDecStmt
- type IndexExpr
- type InterfaceType
- type KeyValueExpr
- type LabeledStmt
- type MapType
- type MergeMode
- type Node
- type ObjKind
- type Object
- type Package
- type ParenExpr
- type RangeStmt
- type ReturnStmt
- type Scope
- type SelectStmt
- type SelectorExpr
- type SendStmt
- type SliceExpr
- type Spec
- type StarExpr
- type Stmt
- type StructType
- type SwitchStmt
- type TypeAssertExpr
- type TypeSpec
- type TypeSwitchStmt
- type UnaryExpr
- type ValueSpec
- type Visitor
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func FileExports ¶
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, and the function bodies of exported functions are set to nil. The File.Comments list is not changed.
FileExports returns true if there are exported declarationa; it returns false otherwise.
func FilterDecl ¶
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 returns true if there are any declared names left after filtering; it returns false otherwise.
func FilterFile ¶
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. The File.Comments list is not changed.
FilterFile returns true if there are any top-level declarations left after filtering; it returns false otherwise.
func FilterPackage ¶
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 returns true if there are any top-level declarations left after filtering; it returns false otherwise.
func Fprint ¶
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 are printed; all others are filtered from the output.
func Inspect ¶
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 for all the non-nil children of node, recursively.
func IsExported ¶
IsExported returns whether name is an exported Go symbol (i.e., whether it begins with an uppercase letter).
func NotNilFilter ¶
NotNilFilter returns true for field values that are not nil; it returns false otherwise.
func PackageExports ¶
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 returns true if there are exported declarations; it returns false otherwise.
func Print ¶
Print prints x to standard output, skipping nil fields. Print(fset, x) is the same as Fprint(os.Stdout, fset, x, NotNilFilter).
Types ¶
type ArrayType ¶
type ArrayType struct { Lbrack token.Pos // position of "[" Len Expr // Ellipsis node for [...]T array types, nil for slice types Elt Expr // element type }
An ArrayType node represents an array or slice type.
type AssignStmt ¶
type AssignStmt struct { Lhs []Expr TokPos token.Pos // position of Tok Tok token.Token // assignment token, DEFINE Rhs []Expr }
An AssignStmt node represents an assignment or a short variable declaration.
func (*AssignStmt) End ¶
func (s *AssignStmt) End() token.Pos
func (*AssignStmt) Pos ¶
func (s *AssignStmt) Pos() token.Pos
type BadDecl ¶
A BadDecl node is a placeholder for declarations containing syntax errors for which no correct declaration nodes can be created.
type BadExpr ¶
A BadExpr node is a placeholder for expressions containing syntax errors for which no correct expression nodes can be created.
type BadStmt ¶
A BadStmt node is a placeholder for statements containing syntax errors for which no correct statement nodes can be created.
type BasicLit ¶
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` }
A BasicLit node represents a literal of basic type.
type BinaryExpr ¶
type BinaryExpr struct { X Expr // left operand OpPos token.Pos // position of Op Op token.Token // operator Y Expr // right operand }
A BinaryExpr node represents a binary expression.
func (*BinaryExpr) End ¶
func (x *BinaryExpr) End() token.Pos
func (*BinaryExpr) Pos ¶
func (x *BinaryExpr) Pos() token.Pos
type BlockStmt ¶
type BlockStmt struct { Lbrace token.Pos // position of "{" List []Stmt Rbrace token.Pos // position of "}" }
A BlockStmt node represents a braced statement list.
type BranchStmt ¶
type BranchStmt struct { TokPos token.Pos // position of Tok Tok token.Token // keyword token (BREAK, CONTINUE, GOTO, FALLTHROUGH) Label *Ident // label name; or nil }
A BranchStmt node represents a break, continue, goto, or fallthrough statement.
func (*BranchStmt) End ¶
func (s *BranchStmt) End() token.Pos
func (*BranchStmt) Pos ¶
func (s *BranchStmt) Pos() token.Pos
type CallExpr ¶
type CallExpr struct { Fun Expr // function expression Lparen token.Pos // position of "(" Args []Expr // function arguments; or nil Ellipsis token.Pos // position of "...", if any Rparen token.Pos // position of ")" }
A CallExpr node represents an expression followed by an argument list.
type CaseClause ¶
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 }
A CaseClause represents a case of an expression or type switch statement.
func (*CaseClause) End ¶
func (s *CaseClause) End() token.Pos
func (*CaseClause) Pos ¶
func (s *CaseClause) Pos() token.Pos
type ChanDir ¶
type ChanDir int
The direction of a channel type is indicated by one of the following constants.
type ChanType ¶
type ChanType struct { Begin token.Pos // position of "chan" keyword or "<-" (whichever comes first) Dir ChanDir // channel direction Value Expr // value type }
A ChanType node represents a channel type.
type CommClause ¶
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 }
A CommClause node represents a case of a select statement.
func (*CommClause) End ¶
func (s *CommClause) End() token.Pos
func (*CommClause) Pos ¶
func (s *CommClause) Pos() token.Pos
type Comment ¶
type Comment struct { Slash token.Pos // position of "/" starting the comment Text string // comment text (excluding '\n' for //-style comments) }
A Comment node represents a single //-style or /*-style comment.
type CommentGroup ¶
type CommentGroup struct {
List []*Comment // len(List) > 0
}
A CommentGroup represents a sequence of comments with no other tokens and no empty lines between.
func (*CommentGroup) End ¶
func (g *CommentGroup) End() token.Pos
func (*CommentGroup) Pos ¶
func (g *CommentGroup) Pos() token.Pos
type CompositeLit ¶
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 "}" }
A CompositeLit node represents a composite literal.
func (*CompositeLit) End ¶
func (x *CompositeLit) End() token.Pos
func (*CompositeLit) Pos ¶
func (x *CompositeLit) Pos() token.Pos
type Decl ¶
type Decl interface { Node // contains filtered or unexported methods }
All declaration nodes implement the Decl interface.
type DeclStmt ¶
type DeclStmt struct {
Decl Decl
}
A DeclStmt node represents a declaration in a statement list.
type Ellipsis ¶
type Ellipsis struct { Ellipsis token.Pos // position of "..." Elt Expr // ellipsis element type (parameter lists only); or nil }
An Ellipsis node stands for the "..." type in a parameter list or the "..." length in an array type.
type EmptyStmt ¶
An EmptyStmt node represents an empty statement. The "position" of the empty statement is the position of the immediately preceding semicolon.
type Expr ¶
type Expr interface { Node // contains filtered or unexported methods }
All expression nodes implement the Expr interface.
type ExprStmt ¶
type ExprStmt struct {
X Expr // expression
}
An ExprStmt node represents a (stand-alone) expression in a statement list.
type Field ¶
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 }
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 FieldFilter ¶
A FieldFilter may be provided to Fprint to control the output.
type FieldList ¶
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 }
A FieldList represents a list of Fields, enclosed by parentheses or braces.
type File ¶
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 }
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.
func MergePackageFiles ¶
MergePackageFiles creates a file AST by merging the ASTs of the files belonging to a package. The mode flags control merging behavior.
type ForStmt ¶
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 }
A ForStmt represents a for statement.
type FuncDecl ¶
type FuncDecl struct { Doc *CommentGroup // associated documentation; or nil Recv *FieldList // receiver (methods); or nil (functions) Name *Ident // function/method name Type *FuncType // position of Func keyword, parameters and results Body *BlockStmt // function body; or nil (forward declaration) }
A FuncDecl node represents a function declaration.
type FuncType ¶
type FuncType struct { Func token.Pos // position of "func" keyword Params *FieldList // (incoming) parameters; or nil Results *FieldList // (outgoing) results; or nil }
A FuncType node represents a function type.
type GenDecl ¶
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 }
A GenDecl node (generic declaration node) represents an import, constant, type or variable declaration. A valid Lparen position (Lparen.Line > 0) 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 Ident ¶
type Ident struct { NamePos token.Pos // identifier position Name string // identifier name Obj *Object // denoted object; or nil }
An Ident node represents an identifier.
func NewIdent ¶
NewIdent creates a new Ident without position. Useful for ASTs generated by code other than the Go parser.
func (*Ident) IsExported ¶
IsExported returns whether id is an exported Go symbol (i.e., whether it begins with an uppercase letter).
type IfStmt ¶
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 }
An IfStmt node represents an if statement.
type ImportSpec ¶
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 }
An ImportSpec node represents a single package import.
func (*ImportSpec) End ¶
func (s *ImportSpec) End() token.Pos
func (*ImportSpec) Pos ¶
func (s *ImportSpec) Pos() token.Pos
Pos and End implementations for spec nodes.
type Importer ¶
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 IncDecStmt ¶
An IncDecStmt node represents an increment or decrement statement.
func (*IncDecStmt) End ¶
func (s *IncDecStmt) End() token.Pos
func (*IncDecStmt) Pos ¶
func (s *IncDecStmt) Pos() token.Pos
type IndexExpr ¶
type IndexExpr struct { X Expr // expression Lbrack token.Pos // position of "[" Index Expr // index expression Rbrack token.Pos // position of "]" }
An IndexExpr node represents an expression followed by an index.
type InterfaceType ¶
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 }
An InterfaceType node represents an interface type.
func (*InterfaceType) End ¶
func (x *InterfaceType) End() token.Pos
func (*InterfaceType) Pos ¶
func (x *InterfaceType) Pos() token.Pos
type KeyValueExpr ¶
A KeyValueExpr node represents (key : value) pairs in composite literals.
func (*KeyValueExpr) End ¶
func (x *KeyValueExpr) End() token.Pos
func (*KeyValueExpr) Pos ¶
func (x *KeyValueExpr) Pos() token.Pos
type LabeledStmt ¶
A LabeledStmt node represents a labeled statement.
func (*LabeledStmt) End ¶
func (s *LabeledStmt) End() token.Pos
func (*LabeledStmt) Pos ¶
func (s *LabeledStmt) Pos() token.Pos
type MergeMode ¶
type MergeMode uint
The MergeMode flags control the behavior of MergePackageFiles.
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 Node ¶
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 }
All node types implement the Node interface.
type ObjKind ¶
type ObjKind int
ObKind describes what an object represents.
type Object ¶
type Object struct { Kind ObjKind Name string // declared name Decl interface{} // corresponding Field, XxxSpec, FuncDecl, or LabeledStmt; or nil Data interface{} // object-specific data; or nil Type interface{} // place holder for type information; may be nil }
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 Con != nil constant value
type 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 }
A Package node represents a set of source files collectively building a Go package.
func NewPackage ¶
func NewPackage(fset *token.FileSet, files map[string]*File, importer Importer, universe *Scope) (*Package, os.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.
type ParenExpr ¶
type ParenExpr struct { Lparen token.Pos // position of "(" X Expr // parenthesized expression Rparen token.Pos // position of ")" }
A ParenExpr node represents a parenthesized expression.
type RangeStmt ¶
type RangeStmt struct { For token.Pos // position of "for" keyword Key, Value Expr // Value may be nil TokPos token.Pos // position of Tok Tok token.Token // ASSIGN, DEFINE X Expr // value to range over Body *BlockStmt }
A RangeStmt represents a for statement with a range clause.
type ReturnStmt ¶
type ReturnStmt struct { Return token.Pos // position of "return" keyword Results []Expr // result expressions; or nil }
A ReturnStmt node represents a return statement.
func (*ReturnStmt) End ¶
func (s *ReturnStmt) End() token.Pos
func (*ReturnStmt) Pos ¶
func (s *ReturnStmt) Pos() token.Pos
type Scope ¶
A Scope maintains the set of named language entities declared in the scope and a link to the immediately surrounding (outer) scope.
func (*Scope) Insert ¶
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."
type SelectStmt ¶
type SelectStmt struct { Select token.Pos // position of "select" keyword Body *BlockStmt // CommClauses only }
An SelectStmt node represents a select statement.
func (*SelectStmt) End ¶
func (s *SelectStmt) End() token.Pos
func (*SelectStmt) Pos ¶
func (s *SelectStmt) Pos() token.Pos
type SelectorExpr ¶
A SelectorExpr node represents an expression followed by a selector.
func (*SelectorExpr) End ¶
func (x *SelectorExpr) End() token.Pos
func (*SelectorExpr) Pos ¶
func (x *SelectorExpr) Pos() token.Pos
type SliceExpr ¶
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 Rbrack token.Pos // position of "]" }
An SliceExpr node represents an expression followed by slice indices.
type Spec ¶
type Spec interface { Node // contains filtered or unexported methods }
The Spec type stands for any of *ImportSpec, *ValueSpec, and *TypeSpec.
type StarExpr ¶
A StarExpr node represents an expression of the form "*" Expression. Semantically it could be a unary "*" expression, or a pointer type.
type Stmt ¶
type Stmt interface { Node // contains filtered or unexported methods }
All statement nodes implement the Stmt interface.
type StructType ¶
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 }
A StructType node represents a struct type.
func (*StructType) End ¶
func (x *StructType) End() token.Pos
func (*StructType) Pos ¶
func (x *StructType) Pos() token.Pos
type SwitchStmt ¶
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 }
A SwitchStmt node represents an expression switch statement.
func (*SwitchStmt) End ¶
func (s *SwitchStmt) End() token.Pos
func (*SwitchStmt) Pos ¶
func (s *SwitchStmt) Pos() token.Pos
type TypeAssertExpr ¶
type TypeAssertExpr struct { X Expr // expression Type Expr // asserted type; nil means type switch X.(type) }
A TypeAssertExpr node represents an expression followed by a type assertion.
func (*TypeAssertExpr) End ¶
func (x *TypeAssertExpr) End() token.Pos
func (*TypeAssertExpr) Pos ¶
func (x *TypeAssertExpr) Pos() token.Pos
type TypeSpec ¶
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 }
A TypeSpec node represents a type declaration (TypeSpec production).
type TypeSwitchStmt ¶
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 }
An TypeSwitchStmt node represents a type switch statement.
func (*TypeSwitchStmt) End ¶
func (s *TypeSwitchStmt) End() token.Pos
func (*TypeSwitchStmt) Pos ¶
func (s *TypeSwitchStmt) Pos() token.Pos
type UnaryExpr ¶
type UnaryExpr struct { OpPos token.Pos // position of Op Op token.Token // operator X Expr // operand }
A UnaryExpr node represents a unary expression. Unary "*" expressions are represented via StarExpr nodes.
type ValueSpec ¶
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 }
A ValueSpec node represents a constant or variable declaration (ConstSpec or VarSpec production).