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