35 lines
861 B
Plaintext
35 lines
861 B
Plaintext
grammar T;
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s : stat ;
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stat: expr[0] NEWLINE
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| ID '=' expr[0] NEWLINE
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| NEWLINE
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;
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expr[int _p]
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: ( INT
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| ID
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| '(' expr[0] ')'
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)
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( {5 >= $_p}? ('*'|'/') expr[6]
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| {4 >= $_p}? ('+'|'-') expr[5]
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)*
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;
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/*
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expr: expr ('*'|'/') expr # MulDiv
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| expr ('+'|'-') expr # AddSub
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| INT # int
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| ID # id
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| '(' expr ')' # parens
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;
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*/
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MUL : '*' ; // assigns token name to '*' used above in grammar
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DIV : '/' ;
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ADD : '+' ;
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SUB : '-' ;
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ID : [a-zA-Z]+ ; // match identifiers
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INT : [0-9]+ ; // match integers
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NEWLINE:'\r'? '\n' ; // return newlines to parser (is end-statement signal)
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WS : [ \t]+ -> skip ; // toss out whitespace
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