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parse static value names #2792

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449a198
feat(parser): parse static value names
KurodaKayn Jul 4, 2026
d91ede5
test(parser): cover static value specs
KurodaKayn Jul 4, 2026
30c1143
test(parser): add static value fixtures
KurodaKayn Jul 4, 2026
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8 changes: 8 additions & 0 deletions parser/_testdata/staticvalues/Rect.gox
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Original file line number Diff line number Diff line change
@@ -0,0 +1,8 @@
const global = 1
const .kind, Rect.name = "shape", "rect"

var (
.count int = 1
Rect.total, .extra int = 2, 3
width int
)
107 changes: 107 additions & 0 deletions parser/_testdata/staticvalues/parser.expect
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Original file line number Diff line number Diff line change
@@ -0,0 +1,107 @@
package main

file Rect.gox
ast.GenDecl:
Tok: const
Specs:
ast.ValueSpec:
Names:
ast.Ident:
Name: global
Values:
ast.BasicLit:
Kind: INT
Value: 1
ast.GenDecl:
Tok: const
Specs:
ast.ValueSpec:
Names:
ast.Ident:
Name: .kind
ast.Ident:
Name: Rect.name
Values:
ast.BasicLit:
Kind: STRING
Value: "shape"
ast.BasicLit:
Kind: STRING
Value: "rect"
ast.GenDecl:
Tok: var
Specs:
ast.ValueSpec:
Names:
ast.Ident:
Name: .count
Type:
ast.Ident:
Name: int
Values:
ast.BasicLit:
Kind: INT
Value: 1
ast.ValueSpec:
Names:
ast.Ident:
Name: Rect.total
ast.Ident:
Name: .extra
Type:
ast.Ident:
Name: int
Values:
ast.BasicLit:
Kind: INT
Value: 2
ast.BasicLit:
Kind: INT
Value: 3
ast.ValueSpec:
Names:
ast.Ident:
Name: width
Type:
ast.Ident:
Name: int

file values.xgo
ast.GenDecl:
Tok: type
Specs:
ast.TypeSpec:
Name:
ast.Ident:
Name: Rect
Type:
ast.Ident:
Name: int
ast.GenDecl:
Tok: const
Specs:
ast.ValueSpec:
Names:
ast.Ident:
Name: Rect.kind
ast.Ident:
Name: global
Values:
ast.BasicLit:
Kind: STRING
Value: "shape"
ast.BasicLit:
Kind: STRING
Value: "global"
ast.GenDecl:
Tok: var
Specs:
ast.ValueSpec:
Names:
ast.Ident:
Name: Rect.count
ast.Ident:
Name: other
Type:
ast.Ident:
Name: int
5 changes: 5 additions & 0 deletions parser/_testdata/staticvalues/values.xgo
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@@ -0,0 +1,5 @@
type Rect int

const Rect.kind, global = "shape", "global"

var Rect.count, other int
196 changes: 101 additions & 95 deletions parser/parser.go
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Expand Up @@ -92,8 +92,6 @@ type parser struct {
syncPos token.Pos // last synchronization position
syncCnt int // number of parser.advance calls without progress

classVarDecl token.Pos // first top-level var declaration in a classfile

// Non-syntactic parser control
exprLev int // < 0: in control clause, >= 0: in expression
inRHS bool // if set, the parser is parsing a rhs expression
Expand Down Expand Up @@ -709,55 +707,47 @@ func (p *parser) parseIdent() *ast.Ident {
return &ast.Ident{NamePos: pos, Name: name}
}

func (p *parser) parseIdentEx() (*ast.Ident, bool) {
var posErr token.Pos
var ret string
if p.inClassFile() && p.tok == token.PERIOD {
posDot := p.pos
func (p *parser) parseValueName(allowDot bool) (*ast.Ident, bool) {
if allowDot && p.tok == token.PERIOD {
dot := p.pos
p.next()
name := p.parseIdent()
ret = "." + name.Name
if posDot+1 == name.NamePos {
return &ast.Ident{NamePos: posDot, Name: ret}, true
}
posErr = name.NamePos
} else {
id := p.parseIdent()
if p.tok != token.PERIOD {
return id, false
}
posDot := p.pos
p.next()
name := p.parseIdent()
ret = id.Name + "." + name.Name
if id.End() == posDot {
if posDot+1 == name.NamePos {
return &ast.Ident{NamePos: id.NamePos, Name: ret}, true
}
posErr = name.NamePos
} else {
posErr = posDot
}
p.checkStaticValueNameSpacing(token.NoPos, dot, name.Pos())
name.NamePos = dot
name.Name = "." + name.Name
return name, true
}
const msg = "whitespace is not allowed in static member name"
p.error(posErr, msg)
return &ast.Ident{NamePos: posErr, Name: ret}, true
name := p.parseIdent()
if p.tok != token.PERIOD {
return name, false
}
dot := p.pos
p.next()
sel := p.parseIdent()
p.checkStaticValueNameSpacing(name.End(), dot, sel.Pos())
name.Name += "." + sel.Name
return name, true
}

func (p *parser) parseIdentList() (list []*ast.Ident, hasStatic bool) {
if p.trace {
defer un(trace(p, "IdentList"))
func (p *parser) checkStaticValueNameSpacing(leftEnd, dot, right token.Pos) {
const msg = "whitespace is not allowed in static value name"
if leftEnd.IsValid() && leftEnd != dot {
p.error(dot, msg)
}
if right != dot+1 {
p.error(right, msg)
}
}

idFirst, hasStatic := p.parseIdentEx()
list = append(list, idFirst)
func (p *parser) parseValueNameList(allowDot bool) (list []*ast.Ident, hasStatic bool) {
name, static := p.parseValueName(allowDot)
list = append(list, name)
hasStatic = static
for p.tok == token.COMMA {
p.next()
idNext, isStatic := p.parseIdentEx()
if isStatic {
hasStatic = true
}
list = append(list, idNext)
name, static = p.parseValueName(allowDot)
list = append(list, name)
hasStatic = hasStatic || static
}
return
}
Expand Down Expand Up @@ -3991,69 +3981,92 @@ func (p *parser) inClassFile() bool {
return p.mode&ParseXGoClass != 0
}

func typeFromIdentEx(id *ast.Ident, isStatic bool) ast.Expr {
if isStatic {
pos := strings.IndexByte(id.Name, '.')
return &ast.SelectorExpr{
X: &ast.Ident{NamePos: id.NamePos, Name: id.Name[:pos]},
Sel: &ast.Ident{NamePos: id.NamePos + token.Pos(pos+1), Name: id.Name[pos+1:]},
}
}
return id
}

func (p *parser) parseValueSpec(doc *ast.CommentGroup, keyword token.Token, iota int) ast.Spec {
if p.trace {
defer un(trace(p, keyword.String()+"Spec"))
func (p *parser) parseClassValueSpec() (idents []*ast.Ident, typ ast.Expr, tag *ast.BasicLit, values []ast.Expr, hasStatic bool) {
var starPos token.Pos
if p.tok == token.MUL {
starPos = p.pos
p.next()
}

pos := p.pos
var idents []*ast.Ident
var hasStatic bool
var typ ast.Expr
var tag *ast.BasicLit
var values []ast.Expr
if p.inClassFile() && p.topScope == p.pkgScope && keyword == token.VAR {
var idFirst *ast.Ident
var starPos token.Pos
if p.tok == token.MUL {
starPos = p.pos
if p.tok == token.PERIOD && starPos == token.NoPos {
idents, hasStatic = p.parseValueNameList(true)
typ = p.tryType()
if p.tok == token.ASSIGN {
p.next()
values = p.parseRHSList()
}
idFirst, hasStatic = p.parseIdentEx()
if starPos != token.NoPos {
typ = &ast.StarExpr{
Star: starPos,
X: typeFromIdentEx(idFirst, hasStatic),
} else {
ident := p.parseIdent()
if p.tok == token.PERIOD {
dot := p.pos
p.next()
selOK := p.tok == token.IDENT
sel := p.parseIdent()
if selOK && starPos == token.NoPos &&
p.tok != token.SEMICOLON && p.tok != token.STRING && p.tok != token.RPAREN {
p.checkStaticValueNameSpacing(ident.End(), dot, sel.Pos())
ident.Name += "." + sel.Name
idents = append(idents, ident)
hasStatic = true
for p.tok == token.COMMA {
p.next()
name, static := p.parseValueName(true)
idents = append(idents, name)
hasStatic = hasStatic || static
}
typ = p.tryType()
if p.tok == token.ASSIGN {
p.next()
values = p.parseRHSList()
}
} else {
typ = &ast.SelectorExpr{X: ident, Sel: sel}
if starPos != token.NoPos {
typ = &ast.StarExpr{Star: starPos, X: typ}
}
}
hasStatic = false
} else if starPos != token.NoPos {
typ = &ast.StarExpr{Star: starPos, X: ident}
} else {
idents = append(idents, idFirst)
idents = append(idents, ident)
for p.tok == token.COMMA {
p.next()
idNext, isStatic := p.parseIdentEx()
if isStatic {
hasStatic = true
}
idents = append(idents, idNext)
name, static := p.parseValueName(true)
idents = append(idents, name)
hasStatic = hasStatic || static
}
typ = p.tryType()
if p.tok == token.ASSIGN {
p.next()
values = p.parseRHSList()
} else if len(idents) == 1 && typ == nil {
typ = typeFromIdentEx(idFirst, hasStatic)
hasStatic = false
typ = ident
idents = nil
}
}
if p.tok == token.STRING {
tag = &ast.BasicLit{ValuePos: p.pos, Kind: p.tok, Value: p.lit}
p.next()
}
p.expect(token.SEMICOLON)
}
if p.tok == token.STRING {
tag = &ast.BasicLit{ValuePos: p.pos, Kind: p.tok, Value: p.lit}
p.next()
}
p.expect(token.SEMICOLON)
return
}

func (p *parser) parseValueSpec(doc *ast.CommentGroup, keyword token.Token, iota int) ast.Spec {
if p.trace {
defer un(trace(p, keyword.String()+"Spec"))
}

pos := p.pos
var idents []*ast.Ident
var typ ast.Expr
var tag *ast.BasicLit
var values []ast.Expr
var hasStatic bool
if p.inClassFile() && p.topScope == p.pkgScope && keyword == token.VAR {
idents, typ, tag, values, hasStatic = p.parseClassValueSpec()
} else {
idents, hasStatic = p.parseIdentList()
idents, hasStatic = p.parseValueNameList(p.inClassFile())
typ = p.tryType()
// always permit optional initialization for more tolerant parsing
if p.tok == token.ASSIGN {
Expand Down Expand Up @@ -4160,13 +4173,6 @@ func (p *parser) parseGenDecl(keyword token.Token, f parseSpecFunction) *ast.Gen
}
doc := p.leadComment
pos := p.expect(keyword)
if keyword == token.VAR && p.inClassFile() && p.topScope == p.pkgScope {
if p.classVarDecl.IsValid() {
p.error(pos, "multiple top-level var declarations in classfile")
} else {
p.classVarDecl = pos
}
}
var lparen, rparen token.Pos
var list []ast.Spec
if p.tok == token.LPAREN {
Expand Down
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