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d: change the return value of yylex from TokenKind to YYParser.Symbol

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The complete symbol approach was deemed to be the right approach for Dlang.
Now, the user can return from yylex() an instance of YYParser.Symbol structure,
which binds together the TokenKind, the semantic value and the location. Before,
the last two were reported separately to the parser.
Only the user API is changed, Bisons's internal structure is kept the same.

* data/skeletons/d.m4 (struct YYParser.Symbol): New.
* data/skeletons/lalr1.d: Change the return value.
* doc/bison.texi: Document it.
* examples/d/calc/calc.y, examples/d/simple/calc.y: Demonstrate it.
* tests/calc.at, tests/scanner.at: Test it.
This commit is contained in:
Adela Vais
2020-11-11 22:35:30 +02:00
committed by Akim Demaille
parent 2ca158c893
commit 10305f3e94
8 changed files with 95 additions and 62 deletions
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20
examples/d/calc/calc.y
View File

@@ -114,7 +114,7 @@ if (isInputRange!R && is(ElementType!R : dchar))
return semanticVal_;
}
TokenKind yylex()
Calc.Symbol yylex()
{
import std.uni : isWhite, isNumber;
@@ -127,7 +127,7 @@ if (isInputRange!R && is(ElementType!R : dchar))
}
if (input.empty)
return TokenKind.YYEOF;
return Calc.Symbol(TokenKind.YYEOF, new YYLocation(startPos, endPos));
// Numbers.
if (input.front.isNumber)
@@ -143,7 +143,7 @@ if (isInputRange!R && is(ElementType!R : dchar))
}
start = end;
end.column += lenChars;
return TokenKind.NUM;
return Calc.Symbol(TokenKind.NUM, semanticVal_.ival, new YYLocation(startPos, endPos));
}
// Individual characters
@@ -153,17 +153,17 @@ if (isInputRange!R && is(ElementType!R : dchar))
end.column++;
switch (ch)
{
case '+': return TokenKind.PLUS;
case '-': return TokenKind.MINUS;
case '*': return TokenKind.STAR;
case '/': return TokenKind.SLASH;
case '(': return TokenKind.LPAR;
case ')': return TokenKind.RPAR;
case '+': return Calc.Symbol(TokenKind.PLUS, new YYLocation(startPos, endPos));
case '-': return Calc.Symbol(TokenKind.MINUS, new YYLocation(startPos, endPos));
case '*': return Calc.Symbol(TokenKind.STAR, new YYLocation(startPos, endPos));
case '/': return Calc.Symbol(TokenKind.SLASH, new YYLocation(startPos, endPos));
case '(': return Calc.Symbol(TokenKind.LPAR, new YYLocation(startPos, endPos));
case ')': return Calc.Symbol(TokenKind.RPAR, new YYLocation(startPos, endPos));
case '\n':
{
end.line++;
end.column = 1;
return TokenKind.EOL;
return Calc.Symbol(TokenKind.EOL, new YYLocation(startPos, endPos));
}
default: assert(0);
}

21
examples/d/simple/calc.y
View File

@@ -109,7 +109,7 @@ if (isInputRange!R && is(ElementType!R : dchar))
return semanticVal_;
}
TokenKind yylex()
Calc.Symbol yylex()
{
import std.uni : isWhite, isNumber;
@@ -118,14 +118,13 @@ if (isInputRange!R && is(ElementType!R : dchar))
input.popFront;
if (input.empty)
return TokenKind.YYEOF;
return Calc.Symbol(TokenKind.YYEOF);
// Numbers.
if (input.front.isNumber)
{
import std.conv : parse;
semanticVal_.ival = input.parse!int;
return TokenKind.NUM;
return Calc.Symbol(TokenKind.NUM, input.parse!int);
}
// Individual characters
@@ -133,13 +132,13 @@ if (isInputRange!R && is(ElementType!R : dchar))
input.popFront;
switch (ch)
{
case '+': return TokenKind.PLUS;
case '-': return TokenKind.MINUS;
case '*': return TokenKind.STAR;
case '/': return TokenKind.SLASH;
case '(': return TokenKind.LPAR;
case ')': return TokenKind.RPAR;
case '\n': return TokenKind.EOL;
case '+': return Calc.Symbol(TokenKind.PLUS);
case '-': return Calc.Symbol(TokenKind.MINUS);
case '*': return Calc.Symbol(TokenKind.STAR);
case '/': return Calc.Symbol(TokenKind.SLASH);
case '(': return Calc.Symbol(TokenKind.LPAR);
case ')': return Calc.Symbol(TokenKind.RPAR);
case '\n': return Calc.Symbol(TokenKind.EOL);
default: assert(0);
}
}