go/ast: implemented NewPackage
NewPackage creates an ast.Package node from
a set of package files and resolves unresolved
identifiers.
Also:
- Changed semantics of Scope.Insert: If an
object is inserted w/o errors, the result
is nil (before it was obj).
- Fixed an identifier resolution bug in the
parser: map keys must not be resolved.
gotype runs through several go/* packages
and successfully resolves all (non-field/method)
identifiers.
R=rog, rsc
CC=golang-dev
https://golang.org/cl/4298044
diff --git a/src/cmd/gotype/gotype.go b/src/cmd/gotype/gotype.go
index 0d57c18..5fa9e28 100644
--- a/src/cmd/gotype/gotype.go
+++ b/src/cmd/gotype/gotype.go
@@ -165,22 +165,24 @@
}
}
}
- processPackage(parseFiles(token.NewFileSet(), filenames[0:i]))
+ fset := token.NewFileSet()
+ processPackage(fset, parseFiles(fset, filenames[0:i]))
}
-func processPackage(files map[string]*ast.File) {
- // TODO(gri) Enable this code once we have ast.NewPackage.
- /*
- // make a package (resolve all identifiers)
- pkg, err := ast.NewPackage(files)
- if err != nil {
- report(err)
- return
- }
- // TODO(gri): typecheck package
- _ = pkg
- */
+// TODO(gri) Replace this with a fully functioning importer.
+// For now a dummy importer is set up by gotype_test.go.
+var importer ast.Importer
+
+func processPackage(fset *token.FileSet, files map[string]*ast.File) {
+ // make a package (resolve all identifiers)
+ pkg, err := ast.NewPackage(fset, files, importer, universe)
+ if err != nil {
+ report(err)
+ return
+ }
+ // TODO(gri): typecheck package
+ _ = pkg
}
@@ -189,10 +191,74 @@
flag.Parse()
if flag.NArg() == 0 {
- processPackage(parseStdin(token.NewFileSet()))
+ fset := token.NewFileSet()
+ processPackage(fset, parseStdin(fset))
} else {
processFiles(flag.Args(), true)
}
os.Exit(exitCode)
}
+
+
+// TODO(gri) Move universe and its initialization in to the right package.
+var universe *ast.Scope
+
+func define(kind ast.ObjKind, names ...string) {
+ for _, name := range names {
+ obj := ast.NewObj(kind, name)
+ if universe.Insert(obj) != nil {
+ panic("gotype internal error: incorrect universe scope")
+ }
+ }
+}
+
+
+func init() {
+ universe = ast.NewScope(nil)
+
+ define(ast.Typ,
+ "bool",
+ "byte",
+ "complex64",
+ "complex128",
+ "float32",
+ "float64",
+ "int8",
+ "int16",
+ "int32",
+ "int64",
+ "string",
+ "uint8",
+ "uint16",
+ "uint32",
+ "uint64",
+ "int",
+ "uint",
+ "uintptr",
+ )
+
+ define(ast.Con,
+ "true",
+ "false",
+ "iota",
+ "nil",
+ )
+
+ define(ast.Fun,
+ "append",
+ "cap",
+ "close",
+ "complex",
+ "copy",
+ "imag",
+ "len",
+ "make",
+ "new",
+ "panic",
+ "print",
+ "println",
+ "real",
+ "recover",
+ )
+}
diff --git a/src/cmd/gotype/gotype_test.go b/src/cmd/gotype/gotype_test.go
index ddd958c..96f54ea 100644
--- a/src/cmd/gotype/gotype_test.go
+++ b/src/cmd/gotype/gotype_test.go
@@ -5,25 +5,36 @@
package main
import (
+ "go/ast"
+ "os"
"path/filepath"
"runtime"
+ "path"
"testing"
)
+func testImporter(importPath string) (string, *ast.Scope, os.Error) {
+ _, pkgName := path.Split(importPath) // filename is package name for std library
+ return pkgName, ast.NewScope(nil), nil
+}
+
+
func testDir(t *testing.T, dir, pkg string) {
+ exitCode = 0
*pkgName = pkg
*recursive = false
+ importer = testImporter
processDirectory(dir)
if exitCode != 0 {
- t.Errorf("processing %d failed: exitCode = %d", dir, exitCode)
+ t.Errorf("processing %s failed: exitCode = %d", dir, exitCode)
}
}
func Test(t *testing.T) {
- testDir(t, ".", "main")
testDir(t, filepath.Join(runtime.GOROOT(), "src/pkg/go/ast"), "ast")
+ testDir(t, filepath.Join(runtime.GOROOT(), "src/pkg/go/token"), "scanner")
testDir(t, filepath.Join(runtime.GOROOT(), "src/pkg/go/scanner"), "scanner")
testDir(t, filepath.Join(runtime.GOROOT(), "src/pkg/go/parser"), "parser")
}
diff --git a/src/pkg/go/ast/Makefile b/src/pkg/go/ast/Makefile
index e9b885c..40be102 100644
--- a/src/pkg/go/ast/Makefile
+++ b/src/pkg/go/ast/Makefile
@@ -9,6 +9,7 @@
ast.go\
filter.go\
print.go\
+ resolve.go\
scope.go\
walk.go\
diff --git a/src/pkg/go/ast/ast.go b/src/pkg/go/ast/ast.go
index 4a4c12b..2023002 100644
--- a/src/pkg/go/ast/ast.go
+++ b/src/pkg/go/ast/ast.go
@@ -781,7 +781,7 @@
ImportSpec struct {
Doc *CommentGroup // associated documentation; or nil
Name *Ident // local package name (including "."); or nil
- Path *BasicLit // package path
+ Path *BasicLit // import path
Comment *CommentGroup // line comments; or nil
}
@@ -925,8 +925,9 @@
Package token.Pos // position of "package" keyword
Name *Ident // package name
Decls []Decl // top-level declarations; or nil
- Scope *Scope // package scope
- Unresolved []*Ident // unresolved global identifiers
+ Scope *Scope // package scope (this file only)
+ Imports []*ImportSpec // imports in this file
+ Unresolved []*Ident // unresolved identifiers in this file
Comments []*CommentGroup // list of all comments in the source file
}
@@ -944,9 +945,10 @@
// collectively building a Go package.
//
type Package struct {
- Name string // package name
- Scope *Scope // package scope
- Files map[string]*File // Go source files by filename
+ Name string // package name
+ Scope *Scope // package scope
+ Imports map[string]*Scope // map of import path -> package scope across all files
+ Files map[string]*File // Go source files by filename
}
diff --git a/src/pkg/go/ast/filter.go b/src/pkg/go/ast/filter.go
index 4da487c..f010bb9 100644
--- a/src/pkg/go/ast/filter.go
+++ b/src/pkg/go/ast/filter.go
@@ -426,5 +426,6 @@
}
// TODO(gri) need to compute pkgScope and unresolved identifiers!
- return &File{doc, pos, NewIdent(pkg.Name), decls, nil, nil, comments}
+ // TODO(gri) need to compute imports!
+ return &File{doc, pos, NewIdent(pkg.Name), decls, nil, nil, nil, comments}
}
diff --git a/src/pkg/go/ast/resolve.go b/src/pkg/go/ast/resolve.go
new file mode 100644
index 0000000..fddc3ba
--- /dev/null
+++ b/src/pkg/go/ast/resolve.go
@@ -0,0 +1,188 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file implements NewPackage.
+
+package ast
+
+import (
+ "fmt"
+ "go/scanner"
+ "go/token"
+ "os"
+)
+
+
+type pkgBuilder struct {
+ scanner.ErrorVector
+ fset *token.FileSet
+}
+
+
+func (p *pkgBuilder) error(pos token.Pos, msg string) {
+ p.Error(p.fset.Position(pos), msg)
+}
+
+
+func (p *pkgBuilder) errorf(pos token.Pos, format string, args ...interface{}) {
+ p.error(pos, fmt.Sprintf(format, args...))
+}
+
+
+func (p *pkgBuilder) declare(scope, altScope *Scope, obj *Object) {
+ alt := scope.Insert(obj)
+ if alt == nil && altScope != nil {
+ // see if there is a conflicting declaration in altScope
+ alt = altScope.Lookup(obj.Name)
+ }
+ if alt != nil {
+ prevDecl := ""
+ if pos := alt.Pos(); pos.IsValid() {
+ prevDecl = fmt.Sprintf("\n\tprevious declaration at %s", p.fset.Position(pos))
+ }
+ p.error(obj.Pos(), fmt.Sprintf("%s redeclared in this block%s", obj.Name, prevDecl))
+ }
+}
+
+
+func resolve(scope *Scope, ident *Ident) bool {
+ for ; scope != nil; scope = scope.Outer {
+ if obj := scope.Lookup(ident.Name); obj != nil {
+ ident.Obj = obj
+ return true
+ }
+ }
+ return false
+}
+
+
+// NewPackage uses an Importer to resolve imports. Given an importPath,
+// an importer returns the imported package's name, its scope of exported
+// objects, and an error, if any.
+//
+type Importer func(path string) (name string, scope *Scope, err os.Error)
+
+
+// NewPackage creates a new Package node from a set of File nodes. It resolves
+// unresolved identifiers across files and updates each file's Unresolved list
+// accordingly. If a non-nil importer and universe scope are provided, they are
+// used to resolve identifiers not declared in any of the package files. Any
+// remaining unresolved identifiers are reported as undeclared. If the files
+// belong to different packages, one package name is selected and files with
+// different package name are reported and then ignored.
+// The result is a package node and a scanner.ErrorList if there were errors.
+//
+func NewPackage(fset *token.FileSet, files map[string]*File, importer Importer, universe *Scope) (*Package, os.Error) {
+ var p pkgBuilder
+ p.fset = fset
+
+ // complete package scope
+ pkgName := ""
+ pkgScope := NewScope(universe)
+ for _, file := range files {
+ // package names must match
+ switch name := file.Name.Name; {
+ case pkgName == "":
+ pkgName = name
+ case name != pkgName:
+ p.errorf(file.Package, "package %s; expected %s", name, pkgName)
+ continue // ignore this file
+ }
+
+ // collect top-level file objects in package scope
+ for _, obj := range file.Scope.Objects {
+ p.declare(pkgScope, nil, obj)
+ }
+ }
+
+ // imports maps import paths to package names and scopes
+ // TODO(gri): Eventually we like to get to the import scope from
+ // a package object. Then we can have a map path -> Obj.
+ type importedPkg struct {
+ name string
+ scope *Scope
+ }
+ imports := make(map[string]*importedPkg)
+
+ // complete file scopes with imports and resolve identifiers
+ for _, file := range files {
+ // ignore file if it belongs to a different package
+ // (error has already been reported)
+ if file.Name.Name != pkgName {
+ continue
+ }
+
+ // build file scope by processing all imports
+ importErrors := false
+ fileScope := NewScope(pkgScope)
+ for _, spec := range file.Imports {
+ // add import to global map of imports
+ path := string(spec.Path.Value)
+ path = path[1 : len(path)-1] // strip ""'s
+ pkg := imports[path]
+ if pkg == nil {
+ if importer == nil {
+ importErrors = true
+ continue
+ }
+ name, scope, err := importer(path)
+ if err != nil {
+ p.errorf(spec.Path.Pos(), "could not import %s (%s)", path, err)
+ importErrors = true
+ continue
+ }
+ pkg = &importedPkg{name, scope}
+ imports[path] = pkg
+ // TODO(gri) If a local package name != "." is provided,
+ // global identifier resolution could proceed even if the
+ // import failed. Consider adjusting the logic here a bit.
+ }
+ // local name overrides imported package name
+ name := pkg.name
+ if spec.Name != nil {
+ name = spec.Name.Name
+ }
+ // add import to file scope
+ if name == "." {
+ // merge imported scope with file scope
+ for _, obj := range pkg.scope.Objects {
+ p.declare(fileScope, pkgScope, obj)
+ }
+ } else {
+ // declare imported package object in file scope
+ obj := NewObj(Pkg, name)
+ obj.Decl = spec
+ p.declare(fileScope, pkgScope, obj)
+ }
+ }
+
+ // resolve identifiers
+ if importErrors {
+ // don't use the universe scope without correct imports
+ // (objects in the universe may be shadowed by imports;
+ // with missing imports identifiers might get resolved
+ // wrongly)
+ pkgScope.Outer = nil
+ }
+ i := 0
+ for _, ident := range file.Unresolved {
+ if !resolve(fileScope, ident) {
+ p.errorf(ident.Pos(), "undeclared name: %s", ident.Name)
+ file.Unresolved[i] = ident
+ i++
+ }
+
+ }
+ file.Unresolved = file.Unresolved[0:i]
+ pkgScope.Outer = universe // reset universe scope
+ }
+
+ // collect all import paths and respective package scopes
+ importedScopes := make(map[string]*Scope)
+ for path, pkg := range imports {
+ importedScopes[path] = pkg.scope
+ }
+
+ return &Package{pkgName, pkgScope, importedScopes, files}, p.GetError(scanner.Sorted)
+}
diff --git a/src/pkg/go/ast/scope.go b/src/pkg/go/ast/scope.go
index 91866dc..830d88a 100644
--- a/src/pkg/go/ast/scope.go
+++ b/src/pkg/go/ast/scope.go
@@ -39,16 +39,14 @@
}
-// Insert attempts to insert a named object into the scope s.
-// If the scope does not contain an object with that name yet,
-// Insert inserts the object and returns it. Otherwise, Insert
-// leaves the scope unchanged and returns the object found in
-// the scope instead.
+// Insert attempts to insert a named object obj into the scope s.
+// If the scope already contains an object alt with the same name,
+// Insert leaves the scope unchanged and returns alt. Otherwise
+// it inserts obj and returns nil."
//
func (s *Scope) Insert(obj *Object) (alt *Object) {
if alt = s.Objects[obj.Name]; alt == nil {
s.Objects[obj.Name] = obj
- alt = obj
}
return
}
@@ -101,6 +99,11 @@
return n.Pos()
}
}
+ case *ImportSpec:
+ if d.Name != nil && d.Name.Name == name {
+ return d.Name.Pos()
+ }
+ return d.Path.Pos()
case *ValueSpec:
for _, n := range d.Names {
if n.Name == name {
diff --git a/src/pkg/go/parser/interface.go b/src/pkg/go/parser/interface.go
index cca251b..fc4ae09 100644
--- a/src/pkg/go/parser/interface.go
+++ b/src/pkg/go/parser/interface.go
@@ -159,7 +159,8 @@
name := src.Name.Name
pkg, found := pkgs[name]
if !found {
- pkg = &ast.Package{name, nil, make(map[string]*ast.File)}
+ // TODO(gri) Use NewPackage here; reconsider ParseFiles API.
+ pkg = &ast.Package{name, nil, nil, make(map[string]*ast.File)}
pkgs[name] = pkg
}
pkg.Files[filename] = src
diff --git a/src/pkg/go/parser/parser.go b/src/pkg/go/parser/parser.go
index d2916d9..e5eec6f 100644
--- a/src/pkg/go/parser/parser.go
+++ b/src/pkg/go/parser/parser.go
@@ -148,8 +148,7 @@
// remember the corresponding declaration for redeclaration
// errors and global variable resolution/typechecking phase
obj.Decl = decl
- alt := scope.Insert(obj)
- if alt != obj && p.mode&DeclarationErrors != 0 {
+ if alt := scope.Insert(obj); alt != nil && p.mode&DeclarationErrors != 0 {
prevDecl := ""
if pos := alt.Pos(); pos.IsValid() {
prevDecl = fmt.Sprintf("\n\tprevious declaration at %s", p.file.Position(pos))
@@ -175,8 +174,9 @@
// and are not global => no need to remember the respective
// declaration
alt := p.topScope.Insert(obj)
- if alt == obj {
+ if alt == nil {
n++ // new declaration
+ alt = obj
}
ident.Obj = alt
}
@@ -1151,12 +1151,16 @@
return p.parseLiteralValue(nil)
}
- x := p.parseRhs()
- if keyOk && p.tok == token.COLON {
- colon := p.pos
- p.next()
- x = &ast.KeyValueExpr{x, colon, p.parseElement(false)}
+ x := p.parseExpr(keyOk) // don't resolve if map key
+ if keyOk {
+ if p.tok == token.COLON {
+ colon := p.pos
+ p.next()
+ return &ast.KeyValueExpr{x, colon, p.parseElement(false)}
+ }
+ p.resolve(x) // not a map key
}
+
return x
}
@@ -2247,5 +2251,5 @@
}
// TODO(gri): store p.imports in AST
- return &ast.File{doc, pos, ident, decls, p.pkgScope, p.unresolved[0:i], p.comments}
+ return &ast.File{doc, pos, ident, decls, p.pkgScope, p.imports, p.unresolved[0:i], p.comments}
}
diff --git a/src/pkg/go/typechecker/scope.go b/src/pkg/go/typechecker/scope.go
index bd24f4c..a4bee6e 100644
--- a/src/pkg/go/typechecker/scope.go
+++ b/src/pkg/go/typechecker/scope.go
@@ -33,7 +33,7 @@
//obj.N = n
name.Obj = obj
if name.Name != "_" {
- if alt := scope.Insert(obj); alt != obj {
+ if alt := scope.Insert(obj); alt != nil {
tc.Errorf(name.Pos(), "%s already declared at %s", name.Name, tc.fset.Position(alt.Pos()).String())
}
}
diff --git a/src/pkg/go/typechecker/typechecker.go b/src/pkg/go/typechecker/typechecker.go
index 4fc5647..b5e695d 100644
--- a/src/pkg/go/typechecker/typechecker.go
+++ b/src/pkg/go/typechecker/typechecker.go
@@ -53,7 +53,7 @@
//
func CheckFile(fset *token.FileSet, file *ast.File, importer Importer) os.Error {
// create a single-file dummy package
- pkg := &ast.Package{file.Name.Name, nil, map[string]*ast.File{fset.Position(file.Name.NamePos).Filename: file}}
+ pkg := &ast.Package{file.Name.Name, nil, nil, map[string]*ast.File{fset.Position(file.Name.NamePos).Filename: file}}
return CheckPackage(fset, pkg, importer)
}
@@ -327,8 +327,8 @@
if ftype != nil {
for _, par := range ftype.Params.Objects {
if par.Name != "_" {
- obj := tc.topScope.Insert(par)
- assert(obj == par) // ftype has no double declarations
+ alt := tc.topScope.Insert(par)
+ assert(alt == nil) // ftype has no double declarations
}
}
}
diff --git a/src/pkg/go/typechecker/universe.go b/src/pkg/go/typechecker/universe.go
index cf44349..abc8bbb 100644
--- a/src/pkg/go/typechecker/universe.go
+++ b/src/pkg/go/typechecker/universe.go
@@ -14,7 +14,7 @@
func def(obj *ast.Object) {
alt := Universe.Insert(obj)
- if alt != obj {
+ if alt != nil {
panic("object declared twice")
}
}
