cs375 p. 80

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Operator Precedence Parser

TOKEN expr ()
{ int done;
 TOKEN tok;
 done = 0;
 opstack = NULL;
 opndstack = NULL;
 while (done == 0)
 { tok = gettoken();
 if (EOFFLG == 0)
 switch (tok->tokentype)
 { case IDENTIFIERTOK: case NUMBERTOK:
 pushopnd (tok); break;
 case DELIMITER:
 if (tok->whichval == LPARENTHESIS)
 pushop(tok);
 else if (tok->whichval
 == RPARENTHESIS)
 { while (opstack->tokentype !=
 DELIMITER)
 reduceop();
 popop(); }
 else done = 1;
 break;