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steps towards a simplified parser interface

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minor cleanups (which I did at home before
but missed this morning at work)

R=rsc
CC=golang-dev
https://golang.org/cl/193095
This commit is contained in:
Robert Griesemer 2010-01-25 17:24:50 -08:00
parent a17929090f
commit dc061ffcbe
2 changed files with 30 additions and 12 deletions
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22
src/pkg/go/parser/interface.go
View File

@ -50,6 +50,14 @@ func readSource(filename string, src interface{}) ([]byte, os.Error) {
}
// TODO(gri) Simplify parser interface by splitting these functions
// into two parts: a single Init and a respective xParse
// function. The Init function can be shared.
//
// - the Init function will take a scope
// - if a scope is provided, the parser tracks declarations, otherwise it won't
// ParseExpr parses a Go expression and returns the corresponding
// AST node. The filename and src arguments have the same interpretation
// as for ParseFile. If there is an error, the result expression
@ -62,7 +70,7 @@ func ParseExpr(filename string, src interface{}) (ast.Expr, os.Error) {
}
var p parser
p.init(filename, data, 0)
p.init(filename, data, nil, 0)
return p.parseExpr(), p.GetError(scanner.Sorted)
}
@ -79,7 +87,7 @@ func ParseStmtList(filename string, src interface{}) ([]ast.Stmt, os.Error) {
}
var p parser
p.init(filename, data, 0)
p.init(filename, data, nil, 0)
return p.parseStmtList(), p.GetError(scanner.Sorted)
}
@ -96,7 +104,7 @@ func ParseDeclList(filename string, src interface{}) ([]ast.Decl, os.Error) {
}
var p parser
p.init(filename, data, 0)
p.init(filename, data, nil, 0)
return p.parseDeclList(), p.GetError(scanner.Sorted)
}
@ -126,7 +134,13 @@ func ParseFile(filename string, src interface{}, mode uint) (*ast.File, os.Error
}
var p parser
p.init(filename, data, mode)
// TODO(gri) Remove CheckSemantics flag and code below once
// scope is provided via Init.
var scope *ast.Scope
if mode&CheckSemantics != 0 {
scope = ast.NewScope(nil)
}
p.init(filename, data, scope, mode)
return p.parseFile(), p.GetError(scanner.NoMultiples)
}

20
src/pkg/go/parser/parser.go
View File

@ -42,7 +42,6 @@ type parser struct {
// Tracing/debugging
mode uint // parsing mode
check bool // == (mode & CheckSemantics != 0)
trace bool // == (mode & Trace != 0)
indent uint // indentation used for tracing output
@ -61,6 +60,7 @@ type parser struct {
exprLev int // < 0: in control clause, >= 0: in expression
// Scopes
checkDecl bool // if set, check declarations
pkgScope *ast.Scope
fileScope *ast.Scope
funcScope *ast.Scope
@ -77,13 +77,16 @@ func scannerMode(mode uint) uint {
}
func (p *parser) init(filename string, src []byte, mode uint) {
func (p *parser) init(filename string, src []byte, scope *ast.Scope, mode uint) {
p.scanner.Init(filename, src, p, scannerMode(mode))
p.mode = mode
p.trace = mode&Trace != 0 // for convenience (p.trace is used frequently)
p.check = mode&CheckSemantics != 0 // for convenience (p.check is used frequently)
p.pkgScope = ast.NewScope(nil) // TODO(gri) should probably provide the pkgScope from outside
p.fileScope = ast.NewScope(p.pkgScope)
p.trace = mode&Trace != 0 // for convenience (p.trace is used frequently)
if scope != nil {
p.checkDecl = true
} else {
scope = ast.NewScope(nil) // provide a dummy scope
}
p.pkgScope = scope
p.next()
}
@ -320,7 +323,7 @@ func (p *parser) parseIdentList(kind ast.ObjKind) []*ast.Ident {
func (p *parser) declIdent(scope *ast.Scope, id *ast.Ident) {
ok := scope.Declare(id.Obj)
if p.check && !ok {
if p.checkDecl && !ok {
p.Error(id.Pos(), "'"+id.Name()+"' declared already")
}
}
@ -342,7 +345,7 @@ func (p *parser) declFieldList(scope *ast.Scope, list []*ast.Field) {
func (p *parser) findIdent() *ast.Ident {
pos := p.pos
name := ""
name := "_"
var obj *ast.Object
if p.tok == token.IDENT {
name = string(p.lit)
@ -2033,6 +2036,7 @@ func (p *parser) parseFile() *ast.File {
ident := p.parseIdent(ast.Pkg) // package name is in no scope
p.expectSemi()
p.fileScope = ast.NewScope(p.pkgScope)
var decls []ast.Decl
// Don't bother parsing the rest if we had errors already.