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Revert "cmd/compile/internal/syntax: support for alias declarations"

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This reverts commit 32db3f2756.

Reason: Decision to back out current alias implementation.

For #16339.

Change-Id: Ib05e3d96041d8347e49cae292f66bec791a1fdc8
Reviewed-on: https://go-review.googlesource.com/32825
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Robert Griesemer 2016-11-04 16:27:31 -07:00
parent a1a688fa00
commit 429edcff10
6 changed files with 38 additions and 129 deletions
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31
src/cmd/compile/internal/syntax/nodes.go
View File

@ -25,21 +25,14 @@ func (n *node) Line() uint32 {
return n.line
}
// TODO(gri) clean up init/initFrom once we have a good file pos story
func (n *node) init(p *parser) {
n.pos = uint32(p.pos)
n.line = uint32(p.line)
}
func (n *node) initFrom(a *node) {
n.pos = a.pos
n.line = a.line
}
// ----------------------------------------------------------------------------
// Files
// package PkgName; DeclList[0], DeclList[1], ...
type File struct {
PkgName *Name
DeclList []Decl
@ -56,8 +49,6 @@ type (
aDecl()
}
// Path
// LocalPkgName Path
ImportDecl struct {
LocalPkgName *Name // including "."; nil means no rename present
Path *BasicLit
@ -65,18 +56,6 @@ type (
decl
}
// Name => Orig
AliasDecl struct {
Tok token // Const, Type, Var, or Func
Name *Name
Orig Expr
Group *Group // nil means not part of a group
decl
}
// NameList
// NameList = Values
// NameList Type = Values
ConstDecl struct {
NameList []*Name
Type Expr // nil means no type
@ -85,7 +64,6 @@ type (
decl
}
// Name Type
TypeDecl struct {
Name *Name
Type Expr
@ -94,9 +72,6 @@ type (
decl
}
// NameList Type
// NameList Type = Values
// NameList = Values
VarDecl struct {
NameList []*Name
Type Expr // nil means no type
@ -105,10 +80,6 @@ type (
decl
}
// func Name Type { Body }
// func Name Type
// func Receiver Name Type { Body }
// func Receiver Name Type
FuncDecl struct {
Attr map[string]bool // go:attr map
Recv *Field // nil means regular function
@ -448,8 +419,6 @@ func (simpleStmt) aSimpleStmt() {}
// ----------------------------------------------------------------------------
// Comments
// TODO(gri) Consider renaming to CommentPos, CommentPlacement, etc.
// Kind = Above doesn't make much sense.
type CommentKind uint
const (

98
src/cmd/compile/internal/syntax/parser.go
View File

@ -317,38 +317,16 @@ func (p *parser) importDecl(group *Group) Decl {
return d
}
// AliasSpec = identifier "=>" [ PackageName "." ] identifier .
func (p *parser) aliasDecl(tok token, name *Name, group *Group) Decl {
// no tracing since this is already called from a const/type/var/funcDecl
d := new(AliasDecl)
d.initFrom(&name.node)
// lhs identifier and "=>" have been consumed already
d.Tok = tok
d.Name = name
d.Orig = p.dotname(p.name())
d.Group = group
return d
}
// ConstSpec = IdentifierList [ [ Type ] "=" ExpressionList ] | AliasSpec .
// ConstSpec = IdentifierList [ [ Type ] "=" ExpressionList ] .
func (p *parser) constDecl(group *Group) Decl {
if trace {
defer p.trace("constDecl")()
}
name := p.name()
if p.got(_Rarrow) {
return p.aliasDecl(Const, name, group)
}
d := new(ConstDecl)
d.initFrom(&name.node)
d.init(p)
d.NameList = p.nameList(name)
d.NameList = p.nameList(p.name())
if p.tok != _EOF && p.tok != _Semi && p.tok != _Rparen {
d.Type = p.tryType()
if p.got(_Assign) {
@ -360,21 +338,16 @@ func (p *parser) constDecl(group *Group) Decl {
return d
}
// TypeSpec = identifier Type | AliasSpec .
// TypeSpec = identifier Type .
func (p *parser) typeDecl(group *Group) Decl {
if trace {
defer p.trace("typeDecl")()
}
name := p.name()
if p.got(_Rarrow) {
return p.aliasDecl(Type, name, group)
}
d := new(TypeDecl)
d.initFrom(&name.node)
d.init(p)
d.Name = name
d.Name = p.name()
d.Type = p.tryType()
if d.Type == nil {
p.syntax_error("in type declaration")
@ -386,21 +359,16 @@ func (p *parser) typeDecl(group *Group) Decl {
return d
}
// VarSpec = IdentifierList ( Type [ "=" ExpressionList ] | "=" ExpressionList ) | AliasSpec .
// VarSpec = IdentifierList ( Type [ "=" ExpressionList ] | "=" ExpressionList ) .
func (p *parser) varDecl(group *Group) Decl {
if trace {
defer p.trace("varDecl")()
}
name := p.name()
if p.got(_Rarrow) {
return p.aliasDecl(Var, name, group)
}
d := new(VarDecl)
d.initFrom(&name.node)
d.init(p)
d.NameList = p.nameList(name)
d.NameList = p.nameList(p.name())
if p.got(_Assign) {
d.Values = p.exprList()
} else {
@ -417,28 +385,31 @@ func (p *parser) varDecl(group *Group) Decl {
return d
}
var badRecv = new(Field) // to signal invalid receiver in funcDecl
// FunctionDecl = "func" FunctionName ( Function | Signature ) | "func" AliasSpec .
// FunctionDecl = "func" FunctionName ( Function | Signature ) .
// FunctionName = identifier .
// Function = Signature FunctionBody .
// MethodDecl = "func" Receiver MethodName ( Function | Signature ) .
// Receiver = Parameters .
func (p *parser) funcDecl() Decl {
func (p *parser) funcDecl() *FuncDecl {
if trace {
defer p.trace("funcDecl")()
}
var recv *Field
f := new(FuncDecl)
f.init(p)
badRecv := false
if p.tok == _Lparen {
recv = badRecv
switch list := p.paramList(); len(list) {
rcvr := p.paramList()
switch len(rcvr) {
case 0:
p.error("method has no receiver")
badRecv = true
case 1:
recv = list[0]
f.Recv = rcvr[0]
default:
p.error("method has multiple receivers")
badRecv = true
}
}
@ -448,11 +419,6 @@ func (p *parser) funcDecl() Decl {
return nil
}
name := p.name()
if recv == nil && p.got(_Rarrow) {
return p.aliasDecl(Func, name, nil)
}
// TODO(gri) check for regular functions only
// if name.Sym.Name == "init" {
// name = renameinit()
@ -467,11 +433,7 @@ func (p *parser) funcDecl() Decl {
// }
// }
f := new(FuncDecl)
f.initFrom(&name.node) // TODO(gri) is this the correct position for methods?
f.Recv = recv
f.Name = name
f.Name = p.name()
f.Type = p.funcType()
if gcCompat {
f.node = f.Type.node
@ -486,7 +448,7 @@ func (p *parser) funcDecl() Decl {
// p.error("can only use //go:noescape with external func implementations")
// }
if recv == badRecv {
if badRecv {
return nil // TODO(gri) better solution
}
return f
@ -555,7 +517,7 @@ func (p *parser) unaryExpr() Expr {
return x
}
case _Larrow:
case _Arrow:
// receive op (<-x) or receive-only channel (<-chan E)
p.next()
@ -969,7 +931,7 @@ func (p *parser) tryType() Expr {
p.next()
return indirect(p.type_())
case _Larrow:
case _Arrow:
// recvchantype
p.next()
p.want(_Chan)
@ -1015,7 +977,7 @@ func (p *parser) tryType() Expr {
p.next()
t := new(ChanType)
t.init(p)
if p.got(_Larrow) {
if p.got(_Arrow) {
t.Dir = SendOnly
}
t.Elem = p.chanElem()
@ -1358,7 +1320,7 @@ func (p *parser) paramDecl() *Field {
case _Name:
f.Name = p.name()
switch p.tok {
case _Name, _Star, _Larrow, _Func, _Lbrack, _Chan, _Map, _Struct, _Interface, _Lparen:
case _Name, _Star, _Arrow, _Func, _Lbrack, _Chan, _Map, _Struct, _Interface, _Lparen:
// sym name_or_type
f.Type = p.type_()
@ -1373,7 +1335,7 @@ func (p *parser) paramDecl() *Field {
f.Name = nil
}
case _Larrow, _Star, _Func, _Lbrack, _Chan, _Map, _Struct, _Interface, _Lparen:
case _Arrow, _Star, _Func, _Lbrack, _Chan, _Map, _Struct, _Interface, _Lparen:
// name_or_type
f.Type = p.type_()
@ -1507,7 +1469,7 @@ func (p *parser) simpleStmt(lhs Expr, rangeOk bool) SimpleStmt {
p.next()
return p.newAssignStmt(op, lhs, ImplicitOne)
case _Larrow:
case _Arrow:
// lhs <- rhs
p.next()
s := new(SendStmt)
@ -1860,7 +1822,7 @@ func (p *parser) commClause() *CommClause {
p.next()
lhs := p.exprList()
if _, ok := lhs.(*ListExpr); !ok && p.tok == _Larrow {
if _, ok := lhs.(*ListExpr); !ok && p.tok == _Arrow {
// lhs <- x
} else {
// lhs
@ -1940,7 +1902,7 @@ func (p *parser) stmt() Stmt {
case _Literal, _Func, _Lparen, // operands
_Lbrack, _Struct, _Map, _Chan, _Interface, // composite types
_Larrow: // receive operator
_Arrow: // receive operator
return p.simpleStmt(nil, false)
case _For:

14
src/cmd/compile/internal/syntax/printer.go
View File

@ -473,11 +473,11 @@ func (p *printer) printRawNode(n Node) {
case *ChanType:
if n.Dir == RecvOnly {
p.print(_Larrow)
p.print(_Arrow)
}
p.print(_Chan)
if n.Dir == SendOnly {
p.print(_Larrow)
p.print(_Arrow)
}
p.print(blank, n.Elem)
@ -495,7 +495,7 @@ func (p *printer) printRawNode(n Node) {
p.print(n.X)
case *SendStmt:
p.print(n.Chan, blank, _Larrow, blank, n.Value)
p.print(n.Chan, blank, _Arrow, blank, n.Value)
case *AssignStmt:
p.print(n.Lhs)
@ -603,12 +603,6 @@ func (p *printer) printRawNode(n Node) {
}
p.print(n.Path)
case *AliasDecl:
if n.Group == nil {
p.print(n.Tok, blank)
}
p.print(n.Name, blank, _Rarrow, blank, n.Orig)
case *ConstDecl:
if n.Group == nil {
p.print(_Const, blank)
@ -763,8 +757,6 @@ func groupFor(d Decl) (token, *Group) {
switch d := d.(type) {
case *ImportDecl:
return _Import, d.Group
case *AliasDecl:
return d.Tok, d.Group
case *ConstDecl:
return _Const, d.Group
case *TypeDecl:

9
src/cmd/compile/internal/syntax/scanner.go
View File

@ -229,7 +229,7 @@ redo:
goto assignop
}
if c == '-' {
s.tok = _Larrow
s.tok = _Arrow
break
}
s.ungetr()
@ -253,16 +253,11 @@ redo:
s.tok = _Operator
case '=':
c = s.getr()
if c == '=' {
if s.getr() == '=' {
s.op, s.prec = Eql, precCmp
s.tok = _Operator
break
}
if c == '>' {
s.tok = _Rarrow
break
}
s.ungetr()
s.tok = _Assign

3
src/cmd/compile/internal/syntax/scanner_test.go
View File

@ -210,8 +210,7 @@ var sampleTokens = [...]struct {
{_IncOp, "--", Sub, precAdd},
{_Assign, "=", 0, 0},
{_Define, ":=", 0, 0},
{_Larrow, "<-", 0, 0},
{_Rarrow, "=>", 0, 0},
{_Arrow, "<-", 0, 0},
// delimiters
{_Lparen, "(", 0, 0},

12
src/cmd/compile/internal/syntax/tokens.go
View File

@ -22,8 +22,7 @@ const (
_IncOp
_Assign
_Define
_Larrow
_Rarrow
_Arrow
_Star
// delimitors
@ -70,12 +69,6 @@ const (
)
const (
// for AliasDecl
Const = _Const
Type = _Type
Var = _Var
Func = _Func
// for BranchStmt
Break = _Break
Continue = _Continue
@ -101,8 +94,7 @@ var tokstrings = [...]string{
_IncOp: "opop",
_Assign: "=",
_Define: ":=",
_Larrow: "<-",
_Rarrow: "=>",
_Arrow: "<-",
_Star: "*",
// delimitors