package ast

import “go/ast”

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) 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{}) error func SortImports(fset *token.FileSet, f *File) func Walk(v Visitor, node Node) type ArrayType func (x *ArrayType) End() token.Pos func (x *ArrayType) Pos() token.Pos type AssignStmt func (s *AssignStmt) End() token.Pos func (s *AssignStmt) Pos() token.Pos type BadDecl func (d *BadDecl) End() token.Pos func (d *BadDecl) Pos() token.Pos type BadExpr func (x *BadExpr) End() token.Pos func (x *BadExpr) Pos() token.Pos type BadStmt func (s *BadStmt) End() token.Pos func (s *BadStmt) Pos() token.Pos type BasicLit func (x *BasicLit) End() token.Pos func (x *BasicLit) Pos() token.Pos type BinaryExpr func (x *BinaryExpr) End() token.Pos func (x *BinaryExpr) Pos() token.Pos type BlockStmt func (s *BlockStmt) End() token.Pos func (s *BlockStmt) Pos() token.Pos type BranchStmt func (s *BranchStmt) End() token.Pos func (s *BranchStmt) Pos() token.Pos type CallExpr func (x *CallExpr) End() token.Pos func (x *CallExpr) Pos() token.Pos type CaseClause func (s *CaseClause) End() token.Pos func (s *CaseClause) Pos() token.Pos type ChanDir type ChanType func (x *ChanType) End() token.Pos func (x *ChanType) Pos() token.Pos type CommClause func (s *CommClause) End() token.Pos func (s *CommClause) Pos() token.Pos type Comment func (c *Comment) End() token.Pos func (c *Comment) Pos() token.Pos type CommentGroup func (g *CommentGroup) End() token.Pos func (g *CommentGroup) Pos() token.Pos func (g *CommentGroup) Text() string type CommentMap func NewCommentMap(fset *token.FileSet, node Node, comments []*CommentGroup) CommentMap func (cmap CommentMap) Comments() []*CommentGroup func (cmap CommentMap) Filter(node Node) CommentMap func (cmap CommentMap) String() string func (cmap CommentMap) Update(old, new Node) Node type CompositeLit func (x *CompositeLit) End() token.Pos func (x *CompositeLit) Pos() token.Pos type Decl type DeclStmt func (s *DeclStmt) End() token.Pos func (s *DeclStmt) Pos() token.Pos type DeferStmt func (s *DeferStmt) End() token.Pos func (s *DeferStmt) Pos() token.Pos type Ellipsis func (x *Ellipsis) End() token.Pos func (x *Ellipsis) Pos() token.Pos type EmptyStmt func (s *EmptyStmt) End() token.Pos func (s *EmptyStmt) Pos() token.Pos type Expr type ExprStmt func (s *ExprStmt) End() token.Pos func (s *ExprStmt) Pos() token.Pos type Field func (f *Field) End() token.Pos func (f *Field) Pos() token.Pos type FieldFilter type FieldList func (f *FieldList) End() token.Pos func (f *FieldList) NumFields() int func (f *FieldList) Pos() token.Pos type File func MergePackageFiles(pkg *Package, mode MergeMode) *File func (f *File) End() token.Pos func (f *File) Pos() token.Pos type Filter type ForStmt func (s *ForStmt) End() token.Pos func (s *ForStmt) Pos() token.Pos type FuncDecl func (d *FuncDecl) End() token.Pos func (d *FuncDecl) Pos() token.Pos type FuncLit func (x *FuncLit) End() token.Pos func (x *FuncLit) Pos() token.Pos type FuncType func (x *FuncType) End() token.Pos func (x *FuncType) Pos() token.Pos type GenDecl func (d *GenDecl) End() token.Pos func (d *GenDecl) Pos() token.Pos type GoStmt func (s *GoStmt) End() token.Pos func (s *GoStmt) Pos() token.Pos type Ident func NewIdent(name string) *Ident func (x *Ident) End() token.Pos func (id *Ident) IsExported() bool func (x *Ident) Pos() token.Pos func (id *Ident) String() string type IfStmt func (s *IfStmt) End() token.Pos func (s *IfStmt) Pos() token.Pos type ImportSpec func (s *ImportSpec) End() token.Pos func (s *ImportSpec) Pos() token.Pos type Importer type IncDecStmt func (s *IncDecStmt) End() token.Pos func (s *IncDecStmt) Pos() token.Pos type IndexExpr func (x *IndexExpr) End() token.Pos func (x *IndexExpr) Pos() token.Pos type InterfaceType func (x *InterfaceType) End() token.Pos func (x *InterfaceType) Pos() token.Pos type KeyValueExpr func (x *KeyValueExpr) End() token.Pos func (x *KeyValueExpr) Pos() token.Pos type LabeledStmt func (s *LabeledStmt) End() token.Pos func (s *LabeledStmt) Pos() token.Pos type MapType func (x *MapType) End() token.Pos func (x *MapType) Pos() token.Pos type MergeMode type Node type ObjKind func (kind ObjKind) String() string type Object func NewObj(kind ObjKind, name string) *Object func (obj *Object) Pos() token.Pos type Package func NewPackage(fset *token.FileSet, files map[string]*File, importer Importer, universe *Scope) (*Package, error) func (p *Package) End() token.Pos func (p *Package) Pos() token.Pos type ParenExpr func (x *ParenExpr) End() token.Pos func (x *ParenExpr) Pos() token.Pos type RangeStmt func (s *RangeStmt) End() token.Pos func (s *RangeStmt) Pos() token.Pos type ReturnStmt func (s *ReturnStmt) End() token.Pos func (s *ReturnStmt) Pos() token.Pos type Scope func NewScope(outer *Scope) *Scope func (s *Scope) Insert(obj *Object) (alt *Object) func (s *Scope) Lookup(name string) *Object func (s *Scope) String() string type SelectStmt func (s *SelectStmt) End() token.Pos func (s *SelectStmt) Pos() token.Pos type SelectorExpr func (x *SelectorExpr) End() token.Pos func (x *SelectorExpr) Pos() token.Pos type SendStmt func (s *SendStmt) End() token.Pos func (s *SendStmt) Pos() token.Pos type SliceExpr func (x *SliceExpr) End() token.Pos func (x *SliceExpr) Pos() token.Pos type Spec type StarExpr func (x *StarExpr) End() token.Pos func (x *StarExpr) Pos() token.Pos type Stmt type StructType func (x *StructType) End() token.Pos func (x *StructType) Pos() token.Pos type SwitchStmt func (s *SwitchStmt) End() token.Pos func (s *SwitchStmt) Pos() token.Pos type TypeAssertExpr func (x *TypeAssertExpr) End() token.Pos func (x *TypeAssertExpr) Pos() token.Pos type TypeSpec func (s *TypeSpec) End() token.Pos func (s *TypeSpec) Pos() token.Pos type TypeSwitchStmt func (s *TypeSwitchStmt) End() token.Pos func (s *TypeSwitchStmt) Pos() token.Pos type UnaryExpr func (x *UnaryExpr) End() token.Pos func (x *UnaryExpr) Pos() token.Pos type ValueSpec func (s *ValueSpec) End() token.Pos func (s *ValueSpec) Pos() token.Pos type Visitor Examples

CommentMap Inspect Print Package Files

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

func FileExports ❖ 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 FilterDecl ❖ 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 FilterFile ❖ 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 FilterPackage ❖ 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 Fprint ❖ 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 Inspect ❖ 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 func IsExported ❖ 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 NotNilFilter ❖ func NotNilFilter(_ string, v reflect.Value) bool NotNilFilter returns true for field values that are not nil; it returns false otherwise.

func PackageExports ❖ 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 Print ❖ 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 func SortImports ❖ 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 Walk ❖ 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 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.

func (*ArrayType) End

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

❖ func (x *ArrayType) Pos() token.Pos 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 ❖ type BadDecl struct { From, To token.Pos // position range of bad declaration } A BadDecl node is a placeholder for declarations containing syntax errors for which no correct declaration nodes can be created.

func (*BadDecl) End

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

❖ func (d *BadDecl) Pos() token.Pos type BadExpr ❖ type BadExpr struct { From, To token.Pos // position range of bad expression } A BadExpr node is a placeholder for expressions containing syntax errors for which no correct expression nodes can be created.

func (*BadExpr) End

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

❖ func (x *BadExpr) Pos() token.Pos type BadStmt ❖ type BadStmt struct { From, To token.Pos // position range of bad statement } A BadStmt node is a placeholder for statements containing syntax errors for which no correct statement nodes can be created.

func (*BadStmt) End

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

❖ func (s *BadStmt) Pos() token.Pos 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.

func (*BasicLit) End

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

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

func (*BlockStmt) End

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

❖ func (s *BlockStmt) Pos() token.Pos 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 “…” (token.NoPos if there is no “…”) Rparen token.Pos // position of “)” } A CallExpr node represents an expression followed by an argument list.

func (*CallExpr) End

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

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

❖ const ( SEND ChanDir = 1 << iota RECV ) type ChanType ❖ 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 } A ChanType node represents a channel type.

func (*ChanType) End

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

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

func (*Comment) End

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

❖ func (c *Comment) Pos() token.Pos 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 func (*CommentGroup) Text

❖ 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 CommentMap ❖ type CommentMap map[Node][]*CommentGroup A CommentMap maps an AST node to a list of comment groups associated with it. See NewCommentMap for a description of the association.

Example func NewCommentMap

❖ 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) Comments

❖ 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) Filter

❖ 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) String

❖ func (cmap CommentMap) String() string func (CommentMap) Update

❖ 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 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 // *GenDecl with CONST, TYPE, or VAR token } A DeclStmt node represents a declaration in a statement list.

func (*DeclStmt) End

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

❖ func (s *DeclStmt) Pos() token.Pos type DeferStmt ❖ type DeferStmt struct { Defer token.Pos // position of “defer” keyword Call *CallExpr } A DeferStmt node represents a defer statement.

func (*DeferStmt) End

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

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

func (*Ellipsis) End

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

❖ func (x *Ellipsis) Pos() token.Pos type EmptyStmt ❖ type EmptyStmt struct { Semicolon token.Pos // position of following “;” Implicit bool // if set, “;” was omitted in the source } An EmptyStmt node represents an empty statement. The “position” of the empty statement is the position of the immediately following (explicit or implicit) semicolon.

func (*EmptyStmt) End

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

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

func (*ExprStmt) End

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

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

func (*Field) End

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

❖ func (f *Field) Pos() token.Pos type FieldFilter ❖ type FieldFilter func(name string, value reflect.Value) bool 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.

func (*FieldList) End

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

❖ func (f *FieldList) NumFields() int NumFields returns the number of (named and anonymous fields) in a FieldList.

func (*FieldList) Pos

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

❖ 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) End

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

❖ func (f *File) Pos() token.Pos type Filter ❖ type Filter func(string) bool 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.

func (*ForStmt) End

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

❖ func (s *ForStmt) Pos() token.Pos 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 // function signature: parameters, results, and position of “func” keyword Body *BlockStmt // function body; or nil (forward declaration) } A FuncDecl node represents a function declaration.

func (*FuncDecl) End

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

❖ func (d *FuncDecl) Pos() token.Pos type FuncLit ❖ type FuncLit struct { Type *FuncType // function type Body *BlockStmt // function body } A FuncLit node represents a function literal.

func (*FuncLit) End

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

❖ func (x *FuncLit) Pos() token.Pos type FuncType ❖ 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 } A FuncType node represents a function type.

func (*FuncType) End

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

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

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

❖ func (d *GenDecl) Pos() token.Pos type GoStmt ❖ type GoStmt struct { Go token.Pos // position of “go” keyword Call *CallExpr } A GoStmt node represents a go statement.

func (*GoStmt) End

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

❖ func (s *GoStmt) Pos() token.Pos 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

❖ 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) End

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

❖ 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) Pos

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

❖ func (id *Ident) String() string 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.

func (*IfStmt) End

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

❖ func (s *IfStmt) Pos() token.Pos 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 EndPos token.Pos // end of spec (overrides Path.Pos if nonzero) } 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 type Importer ❖ type Importer func(imports map[string]*Object, path string) (pkg *Object, err error) 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 ❖ type IncDecStmt struct { X Expr TokPos token.Pos // position of Tok Tok token.Token // INC or DEC } 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.

func (*IndexExpr) End

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

❖ func (x *IndexExpr) Pos() token.Pos 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 ❖ type KeyValueExpr struct { Key Expr Colon token.Pos // position of “:” Value Expr } 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 ❖ type LabeledStmt struct { Label *Ident Colon token.Pos // position of “:” Stmt Stmt } 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 MapType ❖ type MapType struct { Map token.Pos // position of “map” keyword Key Expr Value Expr } A MapType node represents a map type.

func (*MapType) End

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

❖ func (x *MapType) 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 ObjKind describes what an object represents.

❖ const ( Bad ObjKind = iota // for error handling Pkg // package Con // constant Typ // type Var // variable Fun // function or method Lbl // label ) The list of possible Object kinds.

func (ObjKind) String

❖ func (kind ObjKind) String() string type Object ❖ 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 } 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 func NewObj

❖ func NewObj(kind ObjKind, name string) *Object NewObj creates a new object of a given kind and name.

func (*Object) Pos

❖ 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 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, 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) End

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

❖ func (p *Package) Pos() token.Pos 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.

func (*ParenExpr) End

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

❖ func (x *ParenExpr) Pos() token.Pos type RangeStmt ❖ 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 } A RangeStmt represents a for statement with a range clause.

func (*RangeStmt) End

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

❖ func (s *RangeStmt) Pos() token.Pos 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 ❖ type Scope struct { Outer *Scope Objects map[string]*Object } A Scope maintains the set of named language entities declared in the scope and a link to the immediately surrounding (outer) scope.

func NewScope

❖ func NewScope(outer *Scope) *Scope NewScope creates a new scope nested in the outer scope.

func (*Scope) Insert

❖ 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) Lookup

❖ 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) String

❖ func (s *Scope) String() string Debugging support

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 ❖ type SelectorExpr struct { X Expr // expression Sel *Ident // field selector } 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 SendStmt ❖ type SendStmt struct { Chan Expr Arrow token.Pos // position of “<-“ Value Expr } A SendStmt node represents a send statement.

func (*SendStmt) End

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

❖ func (s *SendStmt) 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 Max Expr // maximum capacity of slice; or nil Slice3 bool // true if 3-index slice (2 colons present) Rbrack token.Pos // position of “]” } An SliceExpr node represents an expression followed by slice indices.

func (*SliceExpr) End

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

❖ func (x *SliceExpr) Pos() token.Pos type Spec ❖ type Spec interface { Node // contains filtered or unexported methods } The Spec type stands for any of *ImportSpec, *ValueSpec, and *TypeSpec.

type StarExpr ❖ type StarExpr struct { Star token.Pos // position of “” X Expr // operand } A StarExpr node represents an expression of the form “” Expression. Semantically it could be a unary “*” expression, or a pointer type.

func (*StarExpr) End

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

❖ func (x *StarExpr) Pos() token.Pos 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 Lparen token.Pos // position of “(“ Type Expr // asserted type; nil means type switch X.(type) Rparen token.Pos // position of “)” } 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).

func (*TypeSpec) End

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

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

func (*UnaryExpr) End

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

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

func (*ValueSpec) End

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

❖ func (s *ValueSpec) Pos() token.Pos type Visitor ❖ type Visitor interface { Visit(node Node) (w Visitor) } 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).