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/*======================================================================
DNFWR(V,F)
Disjunctive Normal Form Write.
\Input
\parm{V} is a non-null list of distinct variables.
\parm{F} is a disjunctive normal form with variables in $V$,
written out to the output strem
======================================================================*/
#include "qepcad.h"
void DNFWR(Word V, Word F)
{
Word F1,Fp,T;
Step1: /* Classify the formula F. */
T = FIRST(F);
if (T == OROP) goto Step3;
if (T == ANDOP) goto Step4;
if (T == NOTOP) FAIL("DNFWR","NOTOP not expected.");
if (T == RIGHTOP) FAIL("DNFWR","RIGHTOP not expected.");
if (T == LEFTOP) FAIL("DNFWR","LEFTOP not expected.");
if (T == EQUIOP) FAIL("DNFWR","EQUIPOP not expected.");
Step2: /* Atomic formula. */
ATOMFWR(V,F); goto Return;
Step3: /* Disjunction. */
Fp = RED(F);
if (LENGTH(Fp) == 1) { DNFWR(V,FIRST(Fp)); goto Return; }
ADV(Fp,&F1,&Fp); DNFWR(V,F1);
while (Fp != NIL)
{ ADV(Fp,&F1,&Fp); SWRITE(" "); LGOPWR(T); SWRITE("\n"); DNFWR(V,F1); }
goto Return;
Step4: /* Conjunction. */
Fp = RED(F);
if (LENGTH(Fp) == 1) { DNFWR(V,FIRST(Fp)); goto Return; }
ADV(Fp,&F1,&Fp); DNFWR(V,F1);
while (Fp != NIL)
{ ADV(Fp,&F1,&Fp); SWRITE(" "); LGOPWR(T); SWRITE(" "); DNFWR(V,F1); }
Return: /* Prepare for return. */
return;
}
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