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2.5.2 Grammar Rules for mfcalc
Here are the grammar rules for the multi-function calculator.
Most of them are copied directly from calc; three rules,
those which mention VAR or FNCT, are new.
%% /* The grammar follows. */
input: %empty | input line ;
line:
'\n'
| exp '\n' { printf ("%.10g\n", $1); }
| error '\n' { yyerrok; }
;
exp:
NUM { $$ = $1; }
| VAR { $$ = $1->value.var; }
| VAR '=' exp { $$ = $3; $1->value.var = $3; }
| FNCT '(' exp ')' { $$ = (*($1->value.fnctptr))($3); }
| exp '+' exp { $$ = $1 + $3; }
| exp '-' exp { $$ = $1 - $3; }
| exp '*' exp { $$ = $1 * $3; }
| exp '/' exp { $$ = $1 / $3; }
| '-' exp %prec NEG { $$ = -$2; }
| exp '^' exp { $$ = pow ($1, $3); }
| '(' exp ')' { $$ = $2; }
;
/* End of grammar. */ %%
This document was generated on December 1, 2013 using texi2html 5.0.