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- simplified parser by better factoring

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R=r
OCL=15539
CL=15542
This commit is contained in:
Robert Griesemer 2008-09-19 12:12:28 -07:00
parent 72e3b204e4
commit bf04eefddf
2 changed files with 58 additions and 71 deletions
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118
usr/gri/pretty/parser.go
View File

@ -292,71 +292,24 @@ func (P *Parser) ParseResult() {
}
// Signatures
// Function types
//
// (params)
// (params) type
// (params) (results)
func (P *Parser) ParseSignature() {
P.Trace("Signature");
P.OpenScope();
P.level--;
P.ParseParameters();
P.ParseResult();
P.level++;
P.CloseScope();
P.Ecart();
}
// Named signatures
//
// ident (params)
// ident (params) type
// ident (params) (results)
// (recv) ident (params)
// (recv) ident (params) type
// (recv) ident (params) (results)
func (P *Parser) ParseNamedSignature() *AST.Ident {
P.Trace("NamedSignature");
P.OpenScope();
P.level--;
if P.tok == Scanner.LPAREN {
recv_pos := P.pos;
n := P.ParseParameters();
if n != 1 {
P.Error(recv_pos, "must have exactly one receiver");
panic("UNIMPLEMENTED (ParseNamedSignature)");
// TODO do something useful here
}
}
ident := P.ParseIdent();
P.ParseParameters();
P.ParseResult();
P.level++;
P.CloseScope();
P.Ecart();
return ident;
}
func (P *Parser) ParseFunctionType() {
P.Trace("FunctionType");
typ := P.ParseSignature();
P.OpenScope();
P.level--;
P.ParseParameters();
P.ParseResult();
P.level++;
P.CloseScope();
P.Ecart();
}
@ -365,15 +318,7 @@ func (P *Parser) ParseMethodDecl() {
P.Trace("MethodDecl");
ident := P.ParseIdent();
P.OpenScope();
P.level--;
P.ParseParameters();
//r0 := sig.entries.len;
P.ParseResult();
P.level++;
P.CloseScope();
P.ParseFunctionType();
P.Optional(Scanner.SEMICOLON);
P.Ecart();
@ -453,7 +398,7 @@ func (P *Parser) TryType() bool {
case Scanner.LBRACK: P.ParseArrayType();
case Scanner.CHAN, Scanner.ARROW: P.ParseChannelType();
case Scanner.INTERFACE: P.ParseInterfaceType();
case Scanner.LPAREN: P.ParseSignature();
case Scanner.LPAREN: P.ParseFunctionType();
case Scanner.MAP: P.ParseMapType();
case Scanner.STRUCT: P.ParseStructType();
case Scanner.MUL: P.ParsePointerType();
@ -523,7 +468,7 @@ func (P *Parser) ParseFunctionLit() AST.Expr {
P.Trace("FunctionLit");
P.Expect(Scanner.FUNC);
P.ParseSignature(); // replace this with ParseFunctionType() and it won't work - 6g bug?
P.ParseFunctionType();
P.ParseBlock();
P.Ecart();
@ -639,8 +584,8 @@ func (P *Parser) ParseOperand(ident *AST.Ident) AST.Expr {
}
func (P *Parser) ParseSelectorOrTypeAssertion(x AST.Expr) AST.Expr {
P.Trace("SelectorOrTypeAssertion");
func (P *Parser) ParseSelectorOrTypeGuard(x AST.Expr) AST.Expr {
P.Trace("SelectorOrTypeGuard");
P.Expect(Scanner.PERIOD);
pos := P.pos;
@ -682,6 +627,8 @@ func (P *Parser) ParseCall(x AST.Expr) AST.Expr {
// first arguments could be a type if the call is to "new"
// - exclude type names because they could be expression starts
// - exclude "("'s because function types are not allowed and they indicate an expression
// - still a problem for "new(*T)" (the "*")
// - possibility: make "new" a keyword again (or disallow "*" types in new)
if P.tok != Scanner.IDENT && P.tok != Scanner.LPAREN && P.TryType() {
if P.tok == Scanner.COMMA {
P.Next();
@ -706,7 +653,7 @@ func (P *Parser) ParsePrimaryExpr(ident *AST.Ident) AST.Expr {
x := P.ParseOperand(ident);
for {
switch P.tok {
case Scanner.PERIOD: x = P.ParseSelectorOrTypeAssertion(x);
case Scanner.PERIOD: x = P.ParseSelectorOrTypeGuard(x);
case Scanner.LBRACK: x = P.ParseIndexOrSlice(x);
case Scanner.LPAREN: x = P.ParseCall(x);
default: goto exit;
@ -1221,11 +1168,40 @@ func (P *Parser) ParseDecl(exported bool, keyword int) {
}
// Function declarations
//
// func ident (params)
// func ident (params) type
// func ident (params) (results)
// func (recv) ident (params)
// func (recv) ident (params) type
// func (recv) ident (params) (results)
func (P *Parser) ParseFuncDecl(exported bool) {
P.Trace("FuncDecl");
P.Expect(Scanner.FUNC);
ident := P.ParseNamedSignature();
P.OpenScope();
P.level--;
if P.tok == Scanner.LPAREN {
recv_pos := P.pos;
n := P.ParseParameters();
if n != 1 {
P.Error(recv_pos, "must have exactly one receiver");
}
}
ident := P.ParseIdent();
P.ParseFunctionType();
P.level++;
P.CloseScope();
if P.tok == Scanner.SEMICOLON {
// forward declaration
P.Next();

11
usr/gri/pretty/pretty.go
View File

@ -19,9 +19,20 @@ var (
)
func Usage() {
print("usage: pretty { flags } { files }\n");
Flag.PrintDefaults();
sys.exit(0);
}
func main() {
Flag.Parse();
if Flag.NFlag() == 0 && Flag.NArg() == 0 {
Usage();
}
// process files
for i := 0; i < Flag.NArg(); i++ {
src_file := Flag.Arg(i);