[antlr-interest] Re: Use each token Once -- All required

[Sergey Bogdanov]

There is one idea that works for c++ generator:

XXX {int set=0}:  
({(set & 1)==0}? TokenType1 {set |= 1;}
|{(set & (1<<1))==0}? TokenType2 {set |= (1<<1);}
|{(set & (1<<2))==0}? TokenType2 {set |= (1<<2);}
...
)+;

--- In antlr-interest at yahoogroups.com, "georgehernando" 
<georgehernando at h...> wrote:
> 
> How can I specify a compact syntax for the parser that will define 
a 
> list of token types from the lexer where each type must appear, 
but 
> only one time?
> 
> XXX :  (TokenType1 | TokenType2 | TokenType3 | TokenType4)+;
> doesn't limit the token types to appearing only one time.
> 
> Do I have to specify all permutations?
> 
> XXX :  ( (TokenType1 TokenType2 TokenType3 TokenType4) |
>          (TokenType1 TokenType2 TokenType4 TokenType3) |
>          (TokenType1 TokenType4 TokenType3 TokenType2) |
>          (TokenType4 TokenType2 TokenType3 TokenType1) |
>          (TokenType2 TokenType1 TokenType3 TokenType4) |
>          ....
>         )



 
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