mirror of
https://github.com/golang/go
synced 2024-11-26 07:38:00 -07:00
[dev.typeparams] cmd/compile/internal/syntax: implement parsing of type parameters
Port from dev.go2go prototype branch. The compiler doesn't yet set the syntax.AllowGenerics mode, so parsing of generic code remains disabled. Known issue: The doc strings documenting the specific syntax accepted by parser methods are not all up-to-date. Change-Id: I13d134289fd9330fd0ed7f97c997cca6f23466fd Reviewed-on: https://go-review.googlesource.com/c/go/+/261658 Trust: Robert Griesemer <gri@golang.org> Run-TryBot: Robert Griesemer <gri@golang.org> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Robert Griesemer
parent
617b633917
commit
b627988b0c
@ -459,20 +459,21 @@ func isEmptyFuncDecl(dcl Decl) bool {
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// Declarations
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// list parses a possibly empty, sep-separated list, optionally
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// followed by sep and enclosed by ( and ) or { and }. open is
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// one of _Lparen, or _Lbrace, sep is one of _Comma or _Semi,
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// and close is expected to be the (closing) opposite of open.
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// followed sep, and closed by close. sep must be one of _Comma
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// or _Semi, and close must be one of _Rparen, _Rbrace, or _Rbrack.
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// For each list element, f is called. After f returns true, no
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// more list elements are accepted. list returns the position
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// of the closing token.
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//
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// list = "(" { f sep } ")" |
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// "{" { f sep } "}" . // sep is optional before ")" or "}"
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// list = { f sep } ")" |
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// { f sep } "}" . // "," or ";" is optional before ")", "}" or "]"
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//
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func (p *parser) list(open, sep, close token, f func() bool) Pos {
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p.want(open)
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func (p *parser) list(sep, close token, f func() bool) Pos {
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if debug && (sep != _Comma && sep != _Semi || close != _Rparen && close != _Rbrace && close != _Rbrack) {
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panic("invalid sep or close argument for list")
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}
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var done bool
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done := false
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for p.tok != _EOF && p.tok != close && !done {
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done = f()
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// sep is optional before close
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@ -496,7 +497,8 @@ func (p *parser) appendGroup(list []Decl, f func(*Group) Decl) []Decl {
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if p.tok == _Lparen {
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g := new(Group)
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p.clearPragma()
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p.list(_Lparen, _Semi, _Rparen, func() bool {
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p.next() // must consume "(" after calling clearPragma!
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p.list(_Semi, _Rparen, func() bool {
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list = append(list, f(g))
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return false
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})
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@ -566,7 +568,7 @@ func (p *parser) constDecl(group *Group) Decl {
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return d
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}
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// TypeSpec = identifier [ "=" ] Type .
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// TypeSpec = identifier [ TypeParams ] [ "=" ] Type .
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func (p *parser) typeDecl(group *Group) Decl {
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if trace {
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defer p.trace("typeDecl")()
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@ -578,8 +580,42 @@ func (p *parser) typeDecl(group *Group) Decl {
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d.Pragma = p.takePragma()
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d.Name = p.name()
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d.Alias = p.gotAssign()
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d.Type = p.typeOrNil()
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if p.tok == _Lbrack {
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// array/slice or generic type
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pos := p.pos()
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p.next()
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switch p.tok {
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case _Rbrack:
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p.next()
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d.Type = p.sliceType(pos)
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case _Name:
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// array or generic type
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p.xnest++
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x := p.expr()
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p.xnest--
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if name0, ok := x.(*Name); p.mode&AllowGenerics != 0 && ok && p.tok != _Rbrack {
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// generic type
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d.TParamList = p.paramList(name0, _Rbrack)
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pos := p.pos()
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if p.gotAssign() {
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p.syntaxErrorAt(pos, "generic type cannot be alias")
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}
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d.Type = p.typeOrNil()
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} else {
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// x is the array length expression
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if debug && x == nil {
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panic("internal error: nil expression")
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}
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d.Type = p.arrayType(pos, x)
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}
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default:
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d.Type = p.arrayType(pos, nil)
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}
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} else {
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d.Alias = p.gotAssign()
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d.Type = p.typeOrNil()
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}
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if d.Type == nil {
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d.Type = p.badExpr()
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p.syntaxError("in type declaration")
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@ -613,7 +649,7 @@ func (p *parser) varDecl(group *Group) Decl {
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return d
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}
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// FunctionDecl = "func" FunctionName ( Function | Signature ) .
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// FunctionDecl = "func" FunctionName [ TypeParams ] ( Function | Signature ) .
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// FunctionName = identifier .
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// Function = Signature FunctionBody .
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// MethodDecl = "func" Receiver MethodName ( Function | Signature ) .
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@ -627,8 +663,8 @@ func (p *parser) funcDeclOrNil() *FuncDecl {
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f.pos = p.pos()
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f.Pragma = p.takePragma()
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if p.tok == _Lparen {
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rcvr := p.paramList()
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if p.got(_Lparen) {
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rcvr := p.paramList(nil, _Rparen)
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switch len(rcvr) {
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case 0:
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p.error("method has no receiver")
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@ -647,6 +683,14 @@ func (p *parser) funcDeclOrNil() *FuncDecl {
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}
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f.Name = p.name()
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if p.mode&AllowGenerics != 0 && p.got(_Lbrack) {
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if p.tok == _Rbrack {
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p.syntaxError("empty type parameter list")
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p.next()
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} else {
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f.TParamList = p.paramList(nil, _Rbrack)
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}
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}
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f.Type = p.funcType()
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if p.tok == _Lbrace {
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f.Body = p.funcBody()
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@ -850,13 +894,7 @@ func (p *parser) operand(keep_parens bool) Expr {
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// Optimization: Record presence of ()'s only where needed
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// for error reporting. Don't bother in other cases; it is
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// just a waste of memory and time.
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// Parentheses are not permitted on lhs of := .
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// switch x.Op {
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// case ONAME, ONONAME, OPACK, OTYPE, OLITERAL, OTYPESW:
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// keep_parens = true
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// }
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//
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// Parentheses are not permitted around T in a composite
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// literal T{}. If the next token is a {, assume x is a
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// composite literal type T (it may not be, { could be
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@ -879,19 +917,19 @@ func (p *parser) operand(keep_parens bool) Expr {
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case _Func:
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pos := p.pos()
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p.next()
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t := p.funcType()
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ftyp := p.funcType()
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if p.tok == _Lbrace {
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p.xnest++
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f := new(FuncLit)
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f.pos = pos
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f.Type = t
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f.Type = ftyp
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f.Body = p.funcBody()
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p.xnest--
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return f
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}
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return t
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return ftyp
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case _Lbrack, _Chan, _Map, _Struct, _Interface:
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return p.type_() // othertype
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@ -971,6 +1009,14 @@ loop:
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case _Lbrack:
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p.next()
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if p.tok == _Rbrack {
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// invalid empty instance, slice or index expression; accept but complain
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p.syntaxError("expecting operand")
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p.next()
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break
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}
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p.xnest++
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var i Expr
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@ -986,6 +1032,20 @@ loop:
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p.xnest--
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break
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}
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if p.mode&AllowGenerics != 0 && p.tok == _Comma {
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// x[i, ... (instantiated type)
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// TODO(gri) Suggestion by mdempsky@: Use IndexExpr + ExprList for this case.
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// Then we can get rid of CallExpr.Brackets.
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t := new(CallExpr)
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t.pos = pos
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t.Fun = x
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t.ArgList, _ = p.argList(i, _Rbrack)
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t.Brackets = true
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x = t
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p.xnest--
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break
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}
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}
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// x[i:...
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@ -1022,8 +1082,9 @@ loop:
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case _Lparen:
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t := new(CallExpr)
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t.pos = pos
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p.next()
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t.Fun = x
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t.ArgList, t.HasDots = p.argList()
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t.ArgList, t.HasDots = p.argList(nil, _Rparen)
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x = t
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case _Lbrace:
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@ -1032,10 +1093,20 @@ loop:
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t := unparen(x)
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// determine if '{' belongs to a composite literal or a block statement
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complit_ok := false
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switch t.(type) {
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switch t := t.(type) {
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case *Name, *SelectorExpr:
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if p.xnest >= 0 {
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// x is considered a composite literal type
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// x is possibly a composite literal type
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complit_ok = true
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}
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case *CallExpr:
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if t.Brackets && p.xnest >= 0 {
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// x is possibly a composite literal type
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complit_ok = true
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}
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case *IndexExpr:
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if p.xnest >= 0 {
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// x is possibly a composite literal type
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complit_ok = true
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}
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case *ArrayType, *SliceType, *StructType, *MapType:
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@ -1085,7 +1156,8 @@ func (p *parser) complitexpr() *CompositeLit {
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x.pos = p.pos()
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p.xnest++
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x.Rbrace = p.list(_Lbrace, _Comma, _Rbrace, func() bool {
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p.want(_Lbrace)
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x.Rbrace = p.list(_Comma, _Rbrace, func() bool {
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// value
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e := p.bare_complitexpr()
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if p.tok == _Colon {
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@ -1170,26 +1242,10 @@ func (p *parser) typeOrNil() Expr {
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// '[' oexpr ']' ntype
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// '[' _DotDotDot ']' ntype
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p.next()
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p.xnest++
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if p.got(_Rbrack) {
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// []T
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p.xnest--
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t := new(SliceType)
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t.pos = pos
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t.Elem = p.type_()
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return t
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return p.sliceType(pos)
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}
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// [n]T
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t := new(ArrayType)
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t.pos = pos
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if !p.got(_DotDotDot) {
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t.Len = p.expr()
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}
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p.want(_Rbrack)
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p.xnest--
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t.Elem = p.type_()
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return t
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return p.arrayType(pos, nil)
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case _Chan:
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// _Chan non_recvchantype
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@ -1221,7 +1277,7 @@ func (p *parser) typeOrNil() Expr {
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return p.interfaceType()
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case _Name:
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return p.dotname(p.name())
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return p.qualifiedName(nil)
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case _Lparen:
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p.next()
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@ -1233,6 +1289,27 @@ func (p *parser) typeOrNil() Expr {
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return nil
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}
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func (p *parser) typeInstance(typ Expr) Expr {
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if trace {
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defer p.trace("typeInstance")()
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}
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pos := p.pos()
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p.want(_Lbrack)
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if p.tok == _Rbrack {
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p.error("expecting type")
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p.next()
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return typ
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}
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call := new(CallExpr)
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call.pos = pos
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call.Fun = typ
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call.ArgList, _ = p.argList(nil, _Rbrack)
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call.Brackets = true
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return call
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}
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func (p *parser) funcType() *FuncType {
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if trace {
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defer p.trace("funcType")()
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@ -1240,12 +1317,41 @@ func (p *parser) funcType() *FuncType {
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typ := new(FuncType)
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typ.pos = p.pos()
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typ.ParamList = p.paramList()
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p.want(_Lparen)
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typ.ParamList = p.paramList(nil, _Rparen)
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typ.ResultList = p.funcResult()
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return typ
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}
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// "[" has already been consumed, and pos is its position.
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// If len != nil it is the already consumed array length.
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func (p *parser) arrayType(pos Pos, len Expr) Expr {
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if trace {
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defer p.trace("arrayType")()
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}
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if len == nil && !p.got(_DotDotDot) {
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p.xnest++
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len = p.expr()
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p.xnest--
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}
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p.want(_Rbrack)
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t := new(ArrayType)
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t.pos = pos
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t.Len = len
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t.Elem = p.type_()
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return t
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}
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// "[" and "]" have already been consumed, and pos is the position of "[".
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func (p *parser) sliceType(pos Pos) Expr {
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t := new(SliceType)
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t.pos = pos
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t.Elem = p.type_()
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return t
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}
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func (p *parser) chanElem() Expr {
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if trace {
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defer p.trace("chanElem")()
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@ -1261,22 +1367,6 @@ func (p *parser) chanElem() Expr {
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return typ
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}
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func (p *parser) dotname(name *Name) Expr {
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if trace {
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defer p.trace("dotname")()
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}
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if p.tok == _Dot {
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s := new(SelectorExpr)
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s.pos = p.pos()
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p.next()
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s.X = name
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s.Sel = p.name()
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return s
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}
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return name
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}
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// StructType = "struct" "{" { FieldDecl ";" } "}" .
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func (p *parser) structType() *StructType {
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if trace {
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@ -1287,7 +1377,8 @@ func (p *parser) structType() *StructType {
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typ.pos = p.pos()
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p.want(_Struct)
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p.list(_Lbrace, _Semi, _Rbrace, func() bool {
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p.want(_Lbrace)
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p.list(_Semi, _Rbrace, func() bool {
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p.fieldDecl(typ)
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return false
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})
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@ -1305,9 +1396,56 @@ func (p *parser) interfaceType() *InterfaceType {
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typ.pos = p.pos()
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p.want(_Interface)
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p.list(_Lbrace, _Semi, _Rbrace, func() bool {
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if m := p.methodDecl(); m != nil {
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typ.MethodList = append(typ.MethodList, m)
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p.want(_Lbrace)
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p.list(_Semi, _Rbrace, func() bool {
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switch p.tok {
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case _Name:
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typ.MethodList = append(typ.MethodList, p.methodDecl())
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|
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case _Lparen:
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p.syntaxError("cannot parenthesize embedded type")
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f := new(Field)
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f.pos = p.pos()
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p.next()
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f.Type = p.qualifiedName(nil)
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p.want(_Rparen)
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typ.MethodList = append(typ.MethodList, f)
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case _Type:
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if p.mode&AllowGenerics != 0 {
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// TODO(gri) factor this better
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type_ := new(Name)
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type_.pos = p.pos()
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type_.Value = "type" // cannot have a method named "type"
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p.next()
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if p.tok != _Semi && p.tok != _Rbrace {
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f := new(Field)
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f.pos = p.pos()
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f.Name = type_
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f.Type = p.type_()
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typ.MethodList = append(typ.MethodList, f)
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for p.got(_Comma) {
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f := new(Field)
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f.pos = p.pos()
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f.Name = type_
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f.Type = p.type_()
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typ.MethodList = append(typ.MethodList, f)
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}
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} else {
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p.syntaxError("expecting type")
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}
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break
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}
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fallthrough
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default:
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if p.mode&AllowGenerics != 0 {
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p.syntaxError("expecting method, interface name, or type list")
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p.advance(_Semi, _Rbrace, _Type)
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} else {
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p.syntaxError("expecting method or interface name")
|
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p.advance(_Semi, _Rbrace)
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}
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}
|
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return false
|
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})
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@ -1321,8 +1459,8 @@ func (p *parser) funcResult() []*Field {
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defer p.trace("funcResult")()
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}
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|
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if p.tok == _Lparen {
|
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return p.paramList()
|
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if p.got(_Lparen) {
|
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return p.paramList(nil, _Rparen)
|
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}
|
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|
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pos := p.pos()
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@ -1368,59 +1506,71 @@ func (p *parser) fieldDecl(styp *StructType) {
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case _Name:
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name := p.name()
|
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if p.tok == _Dot || p.tok == _Literal || p.tok == _Semi || p.tok == _Rbrace {
|
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// embed oliteral
|
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// embedded type
|
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typ := p.qualifiedName(name)
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tag := p.oliteral()
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p.addField(styp, pos, nil, typ, tag)
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return
|
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break
|
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}
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|
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// new_name_list ntype oliteral
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// name1, name2, ... Type [ tag ]
|
||||
names := p.nameList(name)
|
||||
typ := p.type_()
|
||||
var typ Expr
|
||||
|
||||
// Careful dance: We don't know if we have an embedded instantiated
|
||||
// type T[P1, P2, ...] or a field T of array/slice type [P]E or []E.
|
||||
if p.mode&AllowGenerics != 0 && len(names) == 1 && p.tok == _Lbrack {
|
||||
typ = p.arrayOrTArgs()
|
||||
if typ, ok := typ.(*CallExpr); ok {
|
||||
// embedded type T[P1, P2, ...]
|
||||
typ.Fun = name // name == names[0]
|
||||
tag := p.oliteral()
|
||||
p.addField(styp, pos, nil, typ, tag)
|
||||
break
|
||||
}
|
||||
} else {
|
||||
// T P
|
||||
typ = p.type_()
|
||||
}
|
||||
|
||||
tag := p.oliteral()
|
||||
|
||||
for _, name := range names {
|
||||
p.addField(styp, name.Pos(), name, typ, tag)
|
||||
}
|
||||
|
||||
case _Lparen:
|
||||
p.next()
|
||||
if p.tok == _Star {
|
||||
// '(' '*' embed ')' oliteral
|
||||
pos := p.pos()
|
||||
p.next()
|
||||
typ := newIndirect(pos, p.qualifiedName(nil))
|
||||
p.want(_Rparen)
|
||||
tag := p.oliteral()
|
||||
p.addField(styp, pos, nil, typ, tag)
|
||||
p.syntaxError("cannot parenthesize embedded type")
|
||||
|
||||
} else {
|
||||
// '(' embed ')' oliteral
|
||||
typ := p.qualifiedName(nil)
|
||||
p.want(_Rparen)
|
||||
tag := p.oliteral()
|
||||
p.addField(styp, pos, nil, typ, tag)
|
||||
p.syntaxError("cannot parenthesize embedded type")
|
||||
}
|
||||
|
||||
case _Star:
|
||||
p.next()
|
||||
if p.got(_Lparen) {
|
||||
// '*' '(' embed ')' oliteral
|
||||
typ := newIndirect(pos, p.qualifiedName(nil))
|
||||
p.want(_Rparen)
|
||||
tag := p.oliteral()
|
||||
p.addField(styp, pos, nil, typ, tag)
|
||||
var typ Expr
|
||||
if p.tok == _Lparen {
|
||||
// *(T)
|
||||
p.syntaxError("cannot parenthesize embedded type")
|
||||
|
||||
p.next()
|
||||
typ = p.qualifiedName(nil)
|
||||
p.got(_Rparen) // no need to complain if missing
|
||||
} else {
|
||||
// '*' embed oliteral
|
||||
typ := newIndirect(pos, p.qualifiedName(nil))
|
||||
tag := p.oliteral()
|
||||
p.addField(styp, pos, nil, typ, tag)
|
||||
// *T
|
||||
typ = p.qualifiedName(nil)
|
||||
}
|
||||
tag := p.oliteral()
|
||||
p.addField(styp, pos, nil, newIndirect(pos, typ), tag)
|
||||
|
||||
case _Lparen:
|
||||
p.syntaxError("cannot parenthesize embedded type")
|
||||
p.next()
|
||||
var typ Expr
|
||||
if p.tok == _Star {
|
||||
// (*T)
|
||||
pos := p.pos()
|
||||
p.next()
|
||||
typ = newIndirect(pos, p.qualifiedName(nil))
|
||||
} else {
|
||||
// (T)
|
||||
typ = p.qualifiedName(nil)
|
||||
}
|
||||
p.got(_Rparen) // no need to complain if missing
|
||||
tag := p.oliteral()
|
||||
p.addField(styp, pos, nil, typ, tag)
|
||||
|
||||
default:
|
||||
p.syntaxError("expecting field name or embedded type")
|
||||
@ -1428,6 +1578,39 @@ func (p *parser) fieldDecl(styp *StructType) {
|
||||
}
|
||||
}
|
||||
|
||||
func (p *parser) arrayOrTArgs() Expr {
|
||||
if trace {
|
||||
defer p.trace("arrayOrTArgs")()
|
||||
}
|
||||
|
||||
pos := p.pos()
|
||||
p.want(_Lbrack)
|
||||
if p.got(_Rbrack) {
|
||||
return p.sliceType(pos)
|
||||
}
|
||||
|
||||
// x [P]E or x[P]
|
||||
args, _ := p.argList(nil, _Rbrack)
|
||||
if len(args) == 1 {
|
||||
if elem := p.typeOrNil(); elem != nil {
|
||||
// x [P]E
|
||||
t := new(ArrayType)
|
||||
t.pos = pos
|
||||
t.Len = args[0]
|
||||
t.Elem = elem
|
||||
return t
|
||||
}
|
||||
}
|
||||
|
||||
// x[P], x[P1, P2], ...
|
||||
t := new(CallExpr)
|
||||
t.pos = pos
|
||||
// t.Fun will be filled in by caller
|
||||
t.ArgList = args
|
||||
t.Brackets = true
|
||||
return t
|
||||
}
|
||||
|
||||
func (p *parser) oliteral() *BasicLit {
|
||||
if p.tok == _Literal {
|
||||
b := new(BasicLit)
|
||||
@ -1449,51 +1632,93 @@ func (p *parser) methodDecl() *Field {
|
||||
defer p.trace("methodDecl")()
|
||||
}
|
||||
|
||||
f := new(Field)
|
||||
f.pos = p.pos()
|
||||
name := p.name()
|
||||
|
||||
// accept potential name list but complain
|
||||
// TODO(gri) We probably don't need this special check anymore.
|
||||
// Nobody writes this kind of code. It's from ancient
|
||||
// Go beginnings.
|
||||
hasNameList := false
|
||||
for p.got(_Comma) {
|
||||
p.name()
|
||||
hasNameList = true
|
||||
}
|
||||
if hasNameList {
|
||||
p.syntaxError("name list not allowed in interface type")
|
||||
// already progressed, no need to advance
|
||||
}
|
||||
|
||||
switch p.tok {
|
||||
case _Name:
|
||||
name := p.name()
|
||||
|
||||
// accept potential name list but complain
|
||||
hasNameList := false
|
||||
for p.got(_Comma) {
|
||||
p.name()
|
||||
hasNameList = true
|
||||
}
|
||||
if hasNameList {
|
||||
p.syntaxError("name list not allowed in interface type")
|
||||
// already progressed, no need to advance
|
||||
}
|
||||
|
||||
f := new(Field)
|
||||
f.pos = name.Pos()
|
||||
if p.tok != _Lparen {
|
||||
// packname
|
||||
f.Type = p.qualifiedName(name)
|
||||
return f
|
||||
}
|
||||
|
||||
case _Lparen:
|
||||
// method
|
||||
f.Name = name
|
||||
f.Type = p.funcType()
|
||||
return f
|
||||
|
||||
case _Lparen:
|
||||
p.syntaxError("cannot parenthesize embedded type")
|
||||
f := new(Field)
|
||||
f.pos = p.pos()
|
||||
p.next()
|
||||
f.Type = p.qualifiedName(nil)
|
||||
p.want(_Rparen)
|
||||
return f
|
||||
case _Lbrack:
|
||||
if p.mode&AllowGenerics != 0 {
|
||||
// Careful dance: We don't know if we have a generic method m[T C](x T)
|
||||
// or an embedded instantiated type T[P1, P2] (we accept generic methods
|
||||
// for generality and robustness of parsing).
|
||||
pos := p.pos()
|
||||
p.next()
|
||||
|
||||
// empty type parameter or argument lists are not permitted
|
||||
if p.tok == _Rbrack {
|
||||
// name[]
|
||||
pos := p.pos()
|
||||
p.next()
|
||||
if p.tok == _Lparen {
|
||||
// name[](
|
||||
p.errorAt(pos, "empty type parameter list")
|
||||
f.Name = name
|
||||
f.Type = p.funcType()
|
||||
} else {
|
||||
p.errorAt(pos, "empty type argument list")
|
||||
f.Type = name
|
||||
}
|
||||
break
|
||||
}
|
||||
|
||||
// A type argument list looks like a parameter list with only
|
||||
// types. Parse a parameter list and decide afterwards.
|
||||
list := p.paramList(nil, _Rbrack)
|
||||
if len(list) > 0 && list[0].Name != nil {
|
||||
// generic method
|
||||
f.Name = name
|
||||
f.Type = p.funcType()
|
||||
// TODO(gri) Record list as type parameter list with f.Type
|
||||
// if we want to type-check the generic method.
|
||||
// For now, report an error so this is not a silent event.
|
||||
p.errorAt(pos, "interface method cannot have type parameters")
|
||||
break
|
||||
}
|
||||
|
||||
// embedded instantiated type
|
||||
call := new(CallExpr)
|
||||
call.pos = pos
|
||||
call.Fun = name
|
||||
call.Brackets = true
|
||||
call.ArgList = make([]Expr, len(list))
|
||||
for i := range list {
|
||||
call.ArgList[i] = list[i].Type
|
||||
}
|
||||
f.Type = call
|
||||
break
|
||||
}
|
||||
fallthrough
|
||||
|
||||
default:
|
||||
p.syntaxError("expecting method or interface name")
|
||||
p.advance(_Semi, _Rbrace)
|
||||
return nil
|
||||
// embedded type
|
||||
f.Type = p.qualifiedName(name)
|
||||
}
|
||||
|
||||
return f
|
||||
}
|
||||
|
||||
// ParameterDecl = [ IdentifierList ] [ "..." ] Type .
|
||||
func (p *parser) paramDeclOrNil() *Field {
|
||||
func (p *parser) paramDeclOrNil(name *Name) *Field {
|
||||
if trace {
|
||||
defer p.trace("paramDecl")()
|
||||
}
|
||||
@ -1501,73 +1726,67 @@ func (p *parser) paramDeclOrNil() *Field {
|
||||
f := new(Field)
|
||||
f.pos = p.pos()
|
||||
|
||||
switch p.tok {
|
||||
case _Name:
|
||||
f.Name = p.name()
|
||||
switch p.tok {
|
||||
case _Name, _Star, _Arrow, _Func, _Lbrack, _Chan, _Map, _Struct, _Interface, _Lparen:
|
||||
// sym name_or_type
|
||||
f.Type = p.type_()
|
||||
|
||||
case _DotDotDot:
|
||||
// sym dotdotdot
|
||||
f.Type = p.dotsType()
|
||||
|
||||
case _Dot:
|
||||
// name_or_type
|
||||
// from dotname
|
||||
f.Type = p.dotname(f.Name)
|
||||
f.Name = nil
|
||||
if p.tok == _Name || name != nil {
|
||||
if name == nil {
|
||||
name = p.name()
|
||||
}
|
||||
|
||||
case _Arrow, _Star, _Func, _Lbrack, _Chan, _Map, _Struct, _Interface, _Lparen:
|
||||
// name_or_type
|
||||
f.Type = p.type_()
|
||||
if p.mode&AllowGenerics != 0 && p.tok == _Lbrack {
|
||||
f.Type = p.arrayOrTArgs()
|
||||
if typ, ok := f.Type.(*CallExpr); ok {
|
||||
typ.Fun = name
|
||||
} else {
|
||||
f.Name = name
|
||||
}
|
||||
return f
|
||||
}
|
||||
|
||||
case _DotDotDot:
|
||||
// dotdotdot
|
||||
f.Type = p.dotsType()
|
||||
if p.tok == _Dot {
|
||||
// name_or_type
|
||||
f.Type = p.qualifiedName(name)
|
||||
return f
|
||||
}
|
||||
|
||||
default:
|
||||
p.syntaxError("expecting )")
|
||||
p.advance(_Comma, _Rparen)
|
||||
return nil
|
||||
f.Name = name
|
||||
}
|
||||
|
||||
return f
|
||||
}
|
||||
|
||||
// ...Type
|
||||
func (p *parser) dotsType() *DotsType {
|
||||
if trace {
|
||||
defer p.trace("dotsType")()
|
||||
if p.tok == _DotDotDot {
|
||||
t := new(DotsType)
|
||||
t.pos = p.pos()
|
||||
p.next()
|
||||
t.Elem = p.typeOrNil()
|
||||
if t.Elem == nil {
|
||||
t.Elem = p.badExpr()
|
||||
p.syntaxError("final argument in variadic function missing type")
|
||||
}
|
||||
f.Type = t
|
||||
return f
|
||||
}
|
||||
|
||||
t := new(DotsType)
|
||||
t.pos = p.pos()
|
||||
|
||||
p.want(_DotDotDot)
|
||||
t.Elem = p.typeOrNil()
|
||||
if t.Elem == nil {
|
||||
t.Elem = p.badExpr()
|
||||
p.syntaxError("final argument in variadic function missing type")
|
||||
f.Type = p.typeOrNil()
|
||||
if f.Name != nil || f.Type != nil {
|
||||
return f
|
||||
}
|
||||
|
||||
return t
|
||||
p.syntaxError("expecting )")
|
||||
p.advance(_Comma, _Rparen)
|
||||
return nil
|
||||
}
|
||||
|
||||
// Parameters = "(" [ ParameterList [ "," ] ] ")" .
|
||||
// ParameterList = ParameterDecl { "," ParameterDecl } .
|
||||
func (p *parser) paramList() (list []*Field) {
|
||||
// "(" or "[" has already been consumed.
|
||||
// If name != nil, it is the first name after "(" or "[".
|
||||
func (p *parser) paramList(name *Name, close token) (list []*Field) {
|
||||
if trace {
|
||||
defer p.trace("paramList")()
|
||||
}
|
||||
|
||||
pos := p.pos()
|
||||
|
||||
var named int // number of parameters that have an explicit name and type
|
||||
p.list(_Lparen, _Comma, _Rparen, func() bool {
|
||||
if par := p.paramDeclOrNil(); par != nil {
|
||||
var named int // number of parameters that have an explicit name and type/bound
|
||||
p.list(_Comma, close, func() bool {
|
||||
par := p.paramDeclOrNil(name)
|
||||
name = nil // 1st name was consumed if present
|
||||
if par != nil {
|
||||
if debug && par.Name == nil && par.Type == nil {
|
||||
panic("parameter without name or type")
|
||||
}
|
||||
@ -1589,30 +1808,30 @@ func (p *parser) paramList() (list []*Field) {
|
||||
}
|
||||
}
|
||||
} else if named != len(list) {
|
||||
// some named => all must be named
|
||||
ok := true
|
||||
// some named => all must have names and types
|
||||
var pos Pos // error position (or unknown)
|
||||
var typ Expr
|
||||
for i := len(list) - 1; i >= 0; i-- {
|
||||
if par := list[i]; par.Type != nil {
|
||||
typ = par.Type
|
||||
if par.Name == nil {
|
||||
ok = false
|
||||
pos = typ.Pos()
|
||||
n := p.newName("_")
|
||||
n.pos = typ.Pos() // correct position
|
||||
n.pos = pos // correct position
|
||||
par.Name = n
|
||||
}
|
||||
} else if typ != nil {
|
||||
par.Type = typ
|
||||
} else {
|
||||
// par.Type == nil && typ == nil => we only have a par.Name
|
||||
ok = false
|
||||
pos = par.Name.Pos()
|
||||
t := p.badExpr()
|
||||
t.pos = par.Name.Pos() // correct position
|
||||
t.pos = pos // correct position
|
||||
par.Type = t
|
||||
}
|
||||
}
|
||||
if !ok {
|
||||
p.syntaxErrorAt(pos, "mixed named and unnamed function parameters")
|
||||
if pos.IsKnown() {
|
||||
p.syntaxErrorAt(pos, "mixed named and unnamed parameters")
|
||||
}
|
||||
}
|
||||
|
||||
@ -2209,15 +2428,21 @@ func (p *parser) stmtList() (l []Stmt) {
|
||||
}
|
||||
|
||||
// Arguments = "(" [ ( ExpressionList | Type [ "," ExpressionList ] ) [ "..." ] [ "," ] ] ")" .
|
||||
func (p *parser) argList() (list []Expr, hasDots bool) {
|
||||
func (p *parser) argList(arg Expr, close token) (list []Expr, hasDots bool) {
|
||||
if trace {
|
||||
defer p.trace("argList")()
|
||||
}
|
||||
|
||||
p.xnest++
|
||||
p.list(_Lparen, _Comma, _Rparen, func() bool {
|
||||
list = append(list, p.expr())
|
||||
hasDots = p.got(_DotDotDot)
|
||||
p.list(_Comma, close, func() bool {
|
||||
if arg == nil {
|
||||
arg = p.expr()
|
||||
}
|
||||
list = append(list, arg)
|
||||
arg = nil
|
||||
if close == _Rparen {
|
||||
hasDots = p.got(_DotDotDot)
|
||||
}
|
||||
return hasDots
|
||||
})
|
||||
p.xnest--
|
||||
@ -2275,18 +2500,32 @@ func (p *parser) qualifiedName(name *Name) Expr {
|
||||
defer p.trace("qualifiedName")()
|
||||
}
|
||||
|
||||
var x Expr
|
||||
switch {
|
||||
case name != nil:
|
||||
// name is provided
|
||||
x = name
|
||||
case p.tok == _Name:
|
||||
name = p.name()
|
||||
x = p.name()
|
||||
default:
|
||||
name = p.newName("_")
|
||||
x = p.newName("_")
|
||||
p.syntaxError("expecting name")
|
||||
p.advance(_Dot, _Semi, _Rbrace)
|
||||
}
|
||||
|
||||
return p.dotname(name)
|
||||
if p.tok == _Dot {
|
||||
s := new(SelectorExpr)
|
||||
s.pos = p.pos()
|
||||
p.next()
|
||||
s.X = x
|
||||
s.Sel = p.name()
|
||||
x = s
|
||||
}
|
||||
|
||||
if p.mode&AllowGenerics != 0 && p.tok == _Lbrack {
|
||||
x = p.typeInstance(x)
|
||||
}
|
||||
|
||||
return x
|
||||
}
|
||||
|
||||
// ExpressionList = Expression { "," Expression } .
|
||||
|
||||
@ -16,6 +16,7 @@ type Mode uint
|
||||
// Modes supported by the parser.
|
||||
const (
|
||||
CheckBranches Mode = 1 << iota // check correct use of labels, break, continue, and goto statements
|
||||
AllowGenerics
|
||||
)
|
||||
|
||||
// Error describes a syntax error. Error implements the error interface.
|
||||
|
||||
Loading…
Reference in New Issue
Block a user