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/*
This file is part of libeval, a simple math expression evaluator
Copyright (C) 2017 Michael Geselbracht, mgeselbracht3@gmail.com
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
%token_type { numEval::TokenType }
%extra_argument { NUMERIC_EVALUATOR* pEval }
%nonassoc VAR ASSIGN SEMCOL.
%left PLUS MINUS.
%right UNIT.
%left DIVIDE MULT.
%include {
#include <assert.h>
#include <libeval/numeric_evaluator.h>
}
%syntax_error {
pEval->parseError("Syntax error");
}
%parse_accept {
pEval->parseOk();
}
main ::= in.
/* Allow multiple statements in input string: x=1; y=2 */
in ::= stmt.
in ::= in stmt.
/* A statement can be empty, an expr or an expr followed by ';' */
stmt ::= ENDS.
stmt ::= expr(A) ENDS. { pEval->parseSetResult(A.valid ? A.dValue : NAN); }
stmt ::= expr SEMCOL. { pEval->parseSetResult(NAN); }
expr(A) ::= VALUE(B). { A.dValue = B.dValue; A.valid=true; }
expr(A) ::= expr(B) UNIT(C). { A.dValue = B.dValue * C.dValue; A.valid=B.valid; }
expr(A) ::= MINUS expr(B). { A.dValue = -B.dValue; A.valid=B.valid; }
expr(A) ::= PLUS expr(B). { A.dValue = B.dValue; A.valid=B.valid; }
expr(A) ::= VAR(B). { A.dValue = pEval->GetVar(B.text); A.valid=true; }
expr(A) ::= VAR(B) ASSIGN expr(C). { pEval->SetVar(B.text, C.dValue); A.dValue = C.dValue; A.valid=false; }
expr(A) ::= expr(B) PLUS expr(C). { A.dValue = B.dValue + C.dValue; A.valid=C.valid; }
expr(A) ::= expr(B) MINUS expr(C). { A.dValue = B.dValue - C.dValue; A.valid=C.valid; }
expr(A) ::= expr(B) MULT expr(C). { A.dValue = B.dValue * C.dValue; A.valid=C.valid; }
expr(A) ::= expr(B) DIVIDE expr(C). {
if( C.dValue != 0.0 )
A.dValue = B.dValue / C.dValue;
else
pEval->parseError( "Divide by zero" );
A.valid = C.valid;
}
expr(A) ::= PARENL expr(B) PARENR. { A.dValue = B.dValue; A.valid = B.valid; }
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