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go/ast: correct end position for Index and TypeAssert expressions

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- added position information for [ and ] brackets of Index and Slice expression nodes
- removed a TODO in go/printer

R=r, rsc
CC=golang-dev
https://golang.org/cl/3867045
This commit is contained in:
Robert Griesemer 2011-01-10 11:26:04 -08:00
parent 2b0a276129
commit 23410ced69
3 changed files with 47 additions and 43 deletions
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15
src/pkg/go/ast/ast.go
View File

@ -232,14 +232,18 @@ type (
// An IndexExpr node represents an expression followed by an index.
IndexExpr struct {
X Expr // expression
Lbrack token.Pos // position of "["
Index Expr // index expression
Rbrack token.Pos // position of "]"
}
// An SliceExpr node represents an expression followed by slice indices.
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 "]"
}
// A TypeAssertExpr node represents an expression followed by a
@ -401,9 +405,14 @@ func (x *FuncLit) End() token.Pos { return x.Body.End() }
func (x *CompositeLit) End() token.Pos { return x.Rbrace + 1 }
func (x *ParenExpr) End() token.Pos { return x.Rparen + 1 }
func (x *SelectorExpr) End() token.Pos { return x.Sel.End() }
func (x *IndexExpr) End() token.Pos { return x.Index.End() }
func (x *SliceExpr) End() token.Pos { return x.High.End() }
func (x *TypeAssertExpr) End() token.Pos { return x.Type.End() }
func (x *IndexExpr) End() token.Pos { return x.Rbrack + 1 }
func (x *SliceExpr) End() token.Pos { return x.Rbrack + 1 }
func (x *TypeAssertExpr) End() token.Pos {
if x.Type != nil {
return x.Type.End()
}
return x.X.End()
}
func (x *CallExpr) End() token.Pos { return x.Rparen + 1 }
func (x *StarExpr) End() token.Pos { return x.X.End() }
func (x *UnaryExpr) End() token.Pos { return x.X.End() }

21
src/pkg/go/parser/parser.go
View File

@ -867,26 +867,27 @@ func (p *parser) parseIndexOrSlice(x ast.Expr) ast.Expr {
defer un(trace(p, "IndexOrSlice"))
}
p.expect(token.LBRACK)
lbrack := p.expect(token.LBRACK)
p.exprLev++
var index ast.Expr
var low, high ast.Expr
isSlice := false
if p.tok != token.COLON {
index = p.parseExpr()
low = p.parseExpr()
}
if p.tok == token.COLON {
isSlice = true
p.next()
var end ast.Expr
if p.tok != token.RBRACK {
end = p.parseExpr()
high = p.parseExpr()
}
x = &ast.SliceExpr{x, index, end}
} else {
x = &ast.IndexExpr{x, index}
}
p.exprLev--
p.expect(token.RBRACK)
rbrack := p.expect(token.RBRACK)
return x
if isSlice {
return &ast.SliceExpr{x, lbrack, low, high, rbrack}
}
return &ast.IndexExpr{x, lbrack, low, rbrack}
}

20
src/pkg/go/printer/nodes.go
View File

@ -139,13 +139,7 @@ func (p *printer) exprList(prev0 token.Pos, list []ast.Expr, depth int, mode exp
prev := p.fset.Position(prev0)
next := p.fset.Position(next0)
line := p.fset.Position(list[0].Pos()).Line
endLine := next.Line
if endLine == 0 {
// TODO(gri): endLine may be incorrect as it is really the beginning
// of the last list entry. There may be only one, very long
// entry in which case line == endLine.
endLine = p.fset.Position(list[len(list)-1].Pos()).Line
}
endLine := p.fset.Position(list[len(list)-1].End()).Line
if prev.IsValid() && prev.Line == line && line == endLine {
// all list entries on a single line
@ -708,13 +702,13 @@ func splitSelector(expr ast.Expr) (body, suffix ast.Expr) {
case *ast.IndexExpr:
body, suffix = splitSelector(x.X)
if body != nil {
suffix = &ast.IndexExpr{suffix, x.Index}
suffix = &ast.IndexExpr{suffix, x.Lbrack, x.Index, x.Rbrack}
return
}
case *ast.SliceExpr:
body, suffix = splitSelector(x.X)
if body != nil {
suffix = &ast.SliceExpr{suffix, x.Low, x.High}
suffix = &ast.SliceExpr{suffix, x.Lbrack, x.Low, x.High, x.Rbrack}
return
}
case *ast.TypeAssertExpr:
@ -837,14 +831,14 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, ctxt exprContext, multi
case *ast.IndexExpr:
// TODO(gri): should treat[] like parentheses and undo one level of depth
p.expr1(x.X, token.HighestPrec, 1, 0, multiLine)
p.print(token.LBRACK)
p.print(x.Lbrack, token.LBRACK)
p.expr0(x.Index, depth+1, multiLine)
p.print(token.RBRACK)
p.print(x.Rbrack, token.RBRACK)
case *ast.SliceExpr:
// TODO(gri): should treat[] like parentheses and undo one level of depth
p.expr1(x.X, token.HighestPrec, 1, 0, multiLine)
p.print(token.LBRACK)
p.print(x.Lbrack, token.LBRACK)
if x.Low != nil {
p.expr0(x.Low, depth+1, multiLine)
}
@ -857,7 +851,7 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, ctxt exprContext, multi
if x.High != nil {
p.expr0(x.High, depth+1, multiLine)
}
p.print(token.RBRACK)
p.print(x.Rbrack, token.RBRACK)
case *ast.CallExpr:
if len(x.Args) > 1 {