astutil

Documentation

Overview

Package astutil contains common utilities for working with the Go AST.

Index

• func AddImport(fset *token.FileSet, f *ast.File, ipath string) (added bool)
• func AddNamedImport(fset *token.FileSet, f *ast.File, name, ipath string) (added bool)
• func DeleteImport(fset *token.FileSet, f *ast.File, path string) (deleted bool)
• func Imports(fset *token.FileSet, f *ast.File) [][]*ast.ImportSpec
• func NodeDescription(n ast.Node) string
• func PathEnclosingInterval(root *ast.File, start, end token.Pos) (path []ast.Node, exact bool)
• func RewriteImport(fset *token.FileSet, f *ast.File, oldPath, newPath string) (rewrote bool)
• func Unparen(e ast.Expr) ast.Expr
• func UsesImport(f *ast.File, path string) (used bool)

Functions

func AddImport

func AddImport(fset *token.FileSet, f *ast.File, ipath string) (added bool)

AddImport adds the import path to the file f, if absent.

func AddNamedImport

func AddNamedImport(fset *token.FileSet, f *ast.File, name, ipath string) (added bool)

AddNamedImport adds the import path to the file f, if absent. If name is not empty, it is used to rename the import.

For example, calling

AddNamedImport(fset, f, "pathpkg", "path")

adds

import pathpkg "path"

func DeleteImport

func DeleteImport(fset *token.FileSet, f *ast.File, path string) (deleted bool)

DeleteImport deletes the import path from the file f, if present.

func Imports

func Imports(fset *token.FileSet, f *ast.File) [][]*ast.ImportSpec

Imports returns the file imports grouped by paragraph.

func NodeDescription

func NodeDescription(n ast.Node) string

NodeDescription returns a description of the concrete type of n suitable for a user interface.

TODO(adonovan): in some cases (e.g. Field, FieldList, Ident, StarExpr) we could be much more specific given the path to the AST root. Perhaps we should do that.

func PathEnclosingInterval

func PathEnclosingInterval(root *ast.File, start, end token.Pos) (path []ast.Node, exact bool)

PathEnclosingInterval returns the node that encloses the source interval [start, end), and all its ancestors up to the AST root.

The definition of "enclosing" used by this function considers additional whitespace abutting a node to be enclosed by it. In this example:

z := x + y // add them
     <-A->
    <----B----->

the ast.BinaryExpr(+) node is considered to enclose interval B even though its [Pos()..End()) is actually only interval A. This behaviour makes user interfaces more tolerant of imperfect input.

This function treats tokens as nodes, though they are not included in the result. e.g. PathEnclosingInterval("+") returns the enclosing ast.BinaryExpr("x + y").

If start==end, the 1-char interval following start is used instead.

The 'exact' result is true if the interval contains only path[0] and perhaps some adjacent whitespace. It is false if the interval overlaps multiple children of path[0], or if it contains only interior whitespace of path[0]. In this example:

z := x + y // add them
  <--C-->     <---E-->
    ^
    D

intervals C, D and E are inexact. C is contained by the z-assignment statement, because it spans three of its children (:=, x, +). So too is the 1-char interval D, because it contains only interior whitespace of the assignment. E is considered interior whitespace of the BlockStmt containing the assignment.

Precondition: [start, end) both lie within the same file as root. TODO(adonovan): return (nil, false) in this case and remove precond. Requires FileSet; see loader.tokenFileContainsPos.

Postcondition: path is never nil; it always contains at least 'root'.

func RewriteImport

func RewriteImport(fset *token.FileSet, f *ast.File, oldPath, newPath string) (rewrote bool)

RewriteImport rewrites any import of path oldPath to path newPath.

func Unparen

func Unparen(e ast.Expr) ast.Expr

Unparen returns e with any enclosing parentheses stripped.

func UsesImport

func UsesImport(f *ast.File, path string) (used bool)

UsesImport reports whether a given import is used.