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