diff options
Diffstat (limited to 'go/ast/astutil/enclosing.go')
| -rw-r--r-- | go/ast/astutil/enclosing.go | 29 |
1 files changed, 13 insertions, 16 deletions
diff --git a/go/ast/astutil/enclosing.go b/go/ast/astutil/enclosing.go index a5c6d6d4f..9fa5aa192 100644 --- a/go/ast/astutil/enclosing.go +++ b/go/ast/astutil/enclosing.go @@ -22,9 +22,9 @@ import ( // additional whitespace abutting a node to be enclosed by it. // In this example: // -// z := x + y // add them -// <-A-> -// <----B-----> +// 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. @@ -43,10 +43,10 @@ import ( // interior whitespace of path[0]. // In this example: // -// z := x + y // add them -// <--C--> <---E--> -// ^ -// D +// 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 (:=, @@ -54,12 +54,11 @@ import ( // 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'. -// +// The resulting path is never empty; it always contains at least the +// 'root' *ast.File. Ideally PathEnclosingInterval would reject +// intervals that lie wholly or partially outside the range of the +// file, but unfortunately ast.File records only the token.Pos of +// the 'package' keyword, but not of the start of the file itself. func PathEnclosingInterval(root *ast.File, start, end token.Pos) (path []ast.Node, exact bool) { // fmt.Printf("EnclosingInterval %d %d\n", start, end) // debugging @@ -135,6 +134,7 @@ func PathEnclosingInterval(root *ast.File, start, end token.Pos) (path []ast.Nod return false // inexact: overlaps multiple children } + // Ensure [start,end) is nondecreasing. if start > end { start, end = end, start } @@ -162,7 +162,6 @@ func PathEnclosingInterval(root *ast.File, start, end token.Pos) (path []ast.Nod // tokenNode is a dummy implementation of ast.Node for a single token. // They are used transiently by PathEnclosingInterval but never escape // this package. -// type tokenNode struct { pos token.Pos end token.Pos @@ -183,7 +182,6 @@ func tok(pos token.Pos, len int) ast.Node { // childrenOf returns the direct non-nil children of ast.Node n. // It may include fake ast.Node implementations for bare tokens. // it is not safe to call (e.g.) ast.Walk on such nodes. -// func childrenOf(n ast.Node) []ast.Node { var children []ast.Node @@ -488,7 +486,6 @@ func (sl byPos) Swap(i, j int) { // 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 NodeDescription(n ast.Node) string { switch n := n.(type) { case *ast.ArrayType: |