void precftn(int r,int t,int s)
{
/* decide a shift/reduce conflict by precedence.*/
/* r is a rule number, t a token number */
/* the conflict is in state s */
/* temp1[t] is changed to reflect the action */
int lp,lt, action;
lp = levprd[r];
lt = toklev[t];
if( PLEVEL(lt) == 0 || PLEVEL(lp) == 0 )
{
/* conflict */
if( foutput != NULL ) fprintf( foutput, "\n%d: shift/reduce conflict (shift %d, red'n %d) on %s",
s, temp1[t], r, symnam(t) );
++zzsrconf;
return;
}
if( PLEVEL(lt) == PLEVEL(lp) ) action = ASSOC(lt);
else if( PLEVEL(lt) > PLEVEL(lp) ) action = RASC; /* shift */
else action = LASC; /* reduce */
switch( action )
{
case BASC: /* error action */
temp1[t] = ERRCODE;
return;
case LASC: /* reduce */
temp1[t] = -r;
return;
}
}
output(){ /* print the output for the states */
int i, j, k, c;
settab();
arrset("yyact");
for( i=0; i<nstate; ++i ){ /* output the stuff for state i */
nolook = (tystate[i]==0);
closure(i);
/* output actions */
aryfil( temp1, nterms+1, 0 );
for( j=0; j<cwset; ++j ){ /* look at the items */
c = *( wsets[j].pitem );
if( c>0 && c<NTBASE && temp1[c]==0 ) temp1[c] = go2(i,c);
}
if( i == 1 ) temp1[1] = ACCEPTCODE;
/* now, we have the shifts; look at the reductions */
lastred = 0;
for( j=0; j<cwset; ++j ){
c = *( wsets[j].pitem );
if( c<=0 ){ /* reduction */
lastred = -c;
for( k=1; k<=nterms; ++k ){
if( ((wsets[j].ws[k>>4])&(1<<(k&017))) != 0 ) {
if( temp1[k] == 0 ) temp1[k] = c;
else if( temp1[k]<0 ){ /* reduce/reduce conflict */
settty();
printf("\n%d: reduce/reduce conflict (red'ns %d and %d ) on %s",
i, -temp1[k], lastred, symnam(k) );
if( -temp1[k] > lastred ) temp1[k] = -lastred;
++zzrrconf;
settab();
}
else { /* potential shift/reduce conflict */
switch( precftn( lastred, k ) ) {
case 0: /* precedence does not apply */
settty();
printf("\n%d: shift/reduce conflict (shift %d, red'n %d) on %s", i,
temp1[k], lastred, symnam(k) );
++zzsrconf;
settab();
break;
case 1: /* reduce */
temp1[k] = -lastred;
break;
case 2: /* error, binary operator */
temp1[k] = ERRCODE;
break;
case 3: /* shift ... leave the entry alone */
break;
}
}
}
}
}
}
wract(i);
}
