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go/ast: ast.Print needs a file set to print position values nicely

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Also removed a TODO (AST nodes have been restructured a while ago).

R=r
CC=golang-dev
https://golang.org/cl/4245077
This commit is contained in:
Robert Griesemer 2011-03-10 12:54:33 -08:00
parent 2099e9fdac
commit f1fee448bc
1 changed files with 15 additions and 15 deletions
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30
src/pkg/go/ast/print.go
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@ -30,15 +30,19 @@ func NotNilFilter(_ string, value reflect.Value) bool {
// 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 Fprint(w io.Writer, x interface{}, f FieldFilter) (n int, err os.Error) {
func Fprint(w io.Writer, fset *token.FileSet, x interface{}, f FieldFilter) (n int, err os.Error) {
// setup printer
p := printer{
output: w,
fset: fset,
filter: f,
ptrmap: make(map[interface{}]int),
last: '\n', // force printing of line number on first line
@ -65,14 +69,15 @@ func Fprint(w io.Writer, x interface{}, f FieldFilter) (n int, err os.Error) {
// Print prints x to standard output, skipping nil fields.
// Print(x) is the same as Fprint(os.Stdout, x, NotNilFilter).
func Print(x interface{}) (int, os.Error) {
return Fprint(os.Stdout, x, NotNilFilter)
// Print(fset, x) is the same as Fprint(os.Stdout, fset, x, NotNilFilter).
func Print(fset *token.FileSet, x interface{}) (int, os.Error) {
return Fprint(os.Stdout, fset, x, NotNilFilter)
}
type printer struct {
output io.Writer
fset *token.FileSet
filter FieldFilter
ptrmap map[interface{}]int // *reflect.PtrValue -> line number
written int // number of bytes written to output
@ -137,16 +142,6 @@ func (p *printer) printf(format string, args ...interface{}) {
// probably be in a different package.
func (p *printer) print(x reflect.Value) {
// Note: This test is only needed because AST nodes
// embed a token.Position, and thus all of them
// understand the String() method (but it only
// applies to the Position field).
// TODO: Should reconsider this AST design decision.
if pos, ok := x.Interface().(token.Position); ok {
p.printf("%s", pos)
return
}
if !NotNilFilter("", x) {
p.printf("nil")
return
@ -212,6 +207,11 @@ func (p *printer) print(x reflect.Value) {
p.printf("}")
default:
p.printf("%v", x.Interface())
value := x.Interface()
// position values can be printed nicely if we have a file set
if pos, ok := value.(token.Pos); ok && p.fset != nil {
value = p.fset.Position(pos)
}
p.printf("%v", value)
}
}