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// [calc.cpp] STYX example: a simple calculator
// necessary includes
#include <iostream>
#include "stdosx.h" // base header STYX library
#include "scn_base.h" // scanner
#include "ptm_gen.h" // term construction
#include "symbols.h" // symbol table
#include "hmap.h" // hash maps
#include "calc_lim.h" // calc scanner table
#include "calc_pim.h" // calc parser table
#include "calc_int.h" // calc language interface
//#undef _G_HAVE_BOOL
//#include <stdiostream.h>
static int evalExp(calcExp ex)
// expression evaluation via generated language interface
{ calcExp x1; calcExp x2; GLS_Tok x3;
if (calcExp_mlt(ex, &x1, &x2)) return evalExp(x1) * evalExp(x2);
if (calcExp_div(ex, &x1, &x2)) return evalExp(x1) / evalExp(x2);
if (calcExp_add(ex, &x1, &x2)) return evalExp(x1) + evalExp(x2);
if (calcExp_sub(ex, &x1, &x2)) return evalExp(x1) - evalExp(x2);
if (calcExp_neg(ex, &x2)) return - evalExp(x2);
if (calcExp_int(ex, &x3)) return atoi(GLS_Tok_string(x3));
BUG; return 0;
}
static void calculate(void)
// parse & eval command line
{ Scn_T pScn; // scan table
Scn_Stream pCstream; // scan stream
PLR_Tab pPlr; // parse table
PT_Cfg pPCfg; // parse configuration
PT_Term pSrc = (PT_Term)NULL; // derivation tree
bool bContinue = C_True; // continue flag
Scn_get_calc(&pScn); // create scan table
pPlr = PLR_get_calc(); // create parse table
pCstream = STREAM_STDIN(pScn); // create scanner from stdin
pPCfg = PT_init(pPlr,pCstream); // create parse configuration
while( bContinue ) // continue process ?
{ calcCmd pCmd; // subterm command
calcExp pExp; // subterm expression
// parse command line and construct derivation tree
// as soon as possible without waiting for EOF ( pre-reduction )
// arguments: parse configuration, start symbol or "" for the first
pSrc = PT_INTERPRETE(pPCfg,"");
// initializes error count with syntax error count
PT_setErrorCnt(PT_synErrorCnt(pPCfg));
// no errors --> eval derivation tree
if( pSrc != (PT_Term)NULL && PT_errorCnt() == 0 )
{
// extract command
assert0( calc_Start_Cmd(pSrc,&pCmd), "");
// end command --> stop process
if( calcCmd_end(pCmd) ) bContinue = C_False;
else
{
// extract expression
assert0( calcCmd_exp(pCmd,&pExp), "");
// eval expression and and print result
cout << evalExp(pExp) << "\n";
}
}
else bContinue = C_False;
if( pSrc != (PT_Term)NULL )
PT_delT(pSrc); // release derivation tree
}
PT_quit(pPCfg); // release parse configuration
Stream_close(pCstream); // close scan stream
Stream_free(pCstream); // release scan stream
Scn_free(pScn); // release scan table
PLR_delTab(pPlr); // release parse table
}
int main(int c, char* argv[])
{
// modul initialisation for hash maps and symbols
MAP_init();
initSymbols();
calc_initSymbols();
// interpreter
calculate();
// modul termination for hash maps and symbols
calc_quitSymbols();
freeSymbols();
MAP_quit();
BUG_CORE;
return 0;
}
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