eeaa2c11ee
git-subtree-dir: thirdparty/jed git-subtree-split: 28c014f0557d8718733182817e0e90086149a765
73 lines
1.8 KiB
Plaintext
73 lines
1.8 KiB
Plaintext
/* description: Parses end executes mathematical expressions. */
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/* lexical grammar */
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%lex
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%%
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\s+ /* skip whitespace */
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[0-9]+("."[0-9]+)?\b return 'NUMBER'
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"n" return 'n'
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"||" return '||'
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"&&" return '&&'
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"?" return '?'
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":" return ':'
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"<=" return '<='
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">=" return '>='
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"<" return '<'
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">" return '>'
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"!=" return '!='
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"==" return '=='
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"%" return '%'
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"(" return '('
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")" return ')'
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<<EOF>> return 'EOF'
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. return 'INVALID'
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/lex
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/* operator associations and precedence */
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%right <code> '?' ':'
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%left '||'
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%left '&&'
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%left '<=' '>=' '<' '>' '!=' '=='
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%left '%'
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%start expressions
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%% /* language grammar */
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expressions
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: e EOF
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{ return { type : 'GROUP', expr: $1 }; }
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;
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e
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: e '?' e ':' e
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{$$ = { type: 'TERNARY', expr: $1, truthy : $3, falsey: $5 }; }
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| e '||' e
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{$$ = { type: "OR", left: $1, right: $3 };}
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| e '&&' e
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{$$ = { type: "AND", left: $1, right: $3 };}
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| e '<' e
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{$$ = { type: 'LT', left: $1, right: $3 }; }
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| e '<=' e
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{$$ = { type: 'LTE', left: $1, right: $3 };}
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| e '>' e
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{$$ = { type: 'GT', left: $1, right: $3 };}
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| e '>=' e
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{$$ = { type: 'GTE', left: $1, right: $3 };}
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| e '!=' e
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{$$ = { type: 'NEQ', left: $1, right: $3 };}
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| e '==' e
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{$$ = { type: 'EQ', left: $1, right: $3 };}
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| e '%' e
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{$$ = { type: 'MOD', left: $1, right: $3 };}
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| '(' e ')'
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{$$ = { type: 'GROUP', expr: $2 }; }
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| 'n'
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{$$ = { type: 'VAR' }; }
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| NUMBER
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{$$ = { type: 'NUM', val: Number(yytext) }; }
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;
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