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84 wiersze
2.2 KiB
84 wiersze
2.2 KiB
%{
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/* compile: leg -o calc.c calc.leg
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* cc -o calc calc.c
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*
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* run: ( echo a=2*3; echo b=3+4; echo c=a*b ) | ./calc
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*/
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#define SYMBOL_PAYLOAD \
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oop value; \
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int defined
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#define SYMBOL_INITIALISE(S) \
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S.value = null; \
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S.defined = false
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#include "object.c"
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// this should stay out of object.c because it manipulates Symbol members defined in this file
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oop update_symbol_value(oop symbol, oop integer)
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{
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//_checkType(symbol, Symbol);
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// For now it will fail with assigning to null
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// because for now we can write "a=2 b=a" because everything is passed by value
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//_checkType(integer, Integer);
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set(symbol, Symbol,value, integer); // checktyype is implicit, and it's ok for symbols to store any object value?
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return symbol;
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}
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#define YYSTYPE oop
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YYSTYPE yylval;
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%}
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start = e:exp { yylval = e }
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exp = - (a:assign { $$ = a }
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| s:sum { $$ = s }
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)
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assign = l:IDENT EQUAL n:sum { $$ = update_symbol_value(l, n) }
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sum = l:prod ### removed PLUS* from beginning and made + a prefix operator just like - instead
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( PLUS+ r:prod { get(l, Integer, value) += get(r, Integer, value) }
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| MINUS r:prod { get(l, Integer, value) -= get(r, Integer, value) }
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)* { $$ = l }
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prod = l:neg
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( MULTI r:neg { get(l, Integer, value) *= get(r, Integer, value) }
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| DIVIDE r:neg { get(l, Integer, value) /= get(r, Integer, value) }
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| MODULO r:neg { get(l, Integer, value) %= get(r, Integer, value) }
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)* { $$ = l }
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neg = MINUS n:neg { set(n, Integer, value, -get(n, Integer, value)); $$ = n }
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| PLUS n:neg { $$ = n } ### moved from sum
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| n:value { $$ = n }
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value = n:NUMBER { $$ = n }
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| NULL { $$ = null; /* For now it doesn't work because of _checktype in update_symbol_value() */ }
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| l:IDENT { $$ = get(l, Symbol, value); // Will result in an assertion failed if ident is undefined }
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- = [ \t\n\r]* ### added newline and carriage return to allow multi-line `programs'
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NUMBER = < [0-9]+ > - { $$ = makeInteger(atoi(yytext)) }
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IDENT = < [a-zA-Z][a-zA-Z0-9_]* > - { $$ = intern(yytext) }
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PLUS = '+' -
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MINUS = '-' -
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MULTI = '*' -
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DIVIDE = '/' -
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MODULO = '%' -
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EQUAL = '=' -
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NULL = 'null' -
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%%
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int main(int argc, char **argv)
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{
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while (yyparse()) {
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println(yylval);
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}
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return 0;
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}
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