Re: a token scanner DFA for indirection operator * ?

RonG <rgesell@mb.sympatico.ca> schreibt:


>I'm trying to write a token scanner for C, and I'm wondering if there is a
>detrministic finite automata (DFA) or state machine for the '*'
>indirection operator(IOP), or if differentiation between the multiply
>operator and the IOP is better left to the parser.


Doesn't '*' have 3 meanings?
1. multiply
2. dereference
3. pointer (in declaration, cast-expression)


>Is it possible to determine '*' with just the previous token and a
>lookahead char, or do I need to introduce a flag?


For (3) the scanner must be able to distinguish between type names and other
identifiers.


>PS. I haven't looke at it yet, but I suspect the same situation can arise
>with '&'.


And with '++' and '--' as prefix or postfix operators, and '+' and '-' as unary
or binary operators...


>[I think your life will be a lot easier if you interpret the tokens in
>the parser, not the lexer. -John]


Agreed.


DoDi

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