void deempty() { /* eliminate references to the empty symol */
/* handles used in list traversals */
PSYMBOL s;
PPRODUCTION p;
if (emptypt == NULL) {
errormsg( "EMPTY SYMBOL MUST BE DEFINED", -1 );
return; /* quit if no analysis possible */
}
/* apply initial markings on all symbols */
for (s = symlist; s != NULL; s = s->next) {
if (TERMINAL(s)) {
/* most terminals are nonempty */
s->state = NONEMPTY;
} else {
/* nonterminals and rules are empty until proven not */
s->state = ISEMPTY;
for (p = s->data; p != NULL; p = p->next) {
p->state = ISEMPTY;
}
}
}
/* the distinguished empty symbol is the exceptional terminal */
emptypt->state = ISEMPTY;
do { /* keep trying until no change is made to the grammar */
change = false;
for (s = symlist; s != NULL; s = s->next) if (NONTERMINAL(s)) {
/* for each nonterminal symbol s */
checkempty( s );
}
} while (change);
/* now use the markup to rewrite rules accounting for emptyness */
for (s = symlist; s != NULL; s = s->next) if (NONTERMINAL(s)) {
/* for each nonterminal symbol s */
cleanempty( s );
}
/* finally, deal with possible empty distinguished symbol */
if (head->state == ISEMPTY) {
/* eliminate the distinguished symbol and the empty symbol! */
head = NULL;
emptypt = NULL;
} else if (head->state == CANBEEMPTY) {
/* we eliminated a bit too much, put it back! */
p = NEWPRODUCTION;
p->data = NEWELEMENT;
p->data->next = NULL;
p->data->data = emptypt;
p->next = head->data;
head->data = p;
/* do not eliminate the empty symbol! */
} else /* head->state == NONEMPTY */ {
/* eliminate the empty symbol! */
emptypt = NULL;
}
}
void finishline(Line * l)
{
int i;
int quick1=false;
int quick2=false;
l->on=false;
//printwholegrid();
switch (l->dir)
{
case DOWN:
// falls through.
case UP:
markgrid(l->geom.x,l->geom.y,l->geom.w,l->geom.h,'|');
SDL_FillRect(screen,&l->geom,SDL_MapRGB(screen->format, 0x00, 0x40, 0x80));
soil(l->geom);
// scan along edges to quickly determine if this
// is going to be complicated.
quick1=true; quick2=true;
for (i=l->geom.y+BLOCKHEIGHT/2;i<l->geom.y+l->geom.h;i++)
{
if (grid[l->geom.x-1][i] != ' ' && grid[l->geom.x-1][i] != '*') quick1=false;
if (grid[l->geom.x+BLOCKWIDTH][i] != ' ' && grid[l->geom.x+BLOCKWIDTH][i] != '*') quick2=false;
}
checkempty(l->geom.x-BLOCKWIDTH/2,l->geom.y+BLOCKHEIGHT/2);
checkempty(l->geom.x+BLOCKWIDTH+BLOCKWIDTH/2/2,l->geom.y+BLOCKHEIGHT/2);
if (!quick1)
for (i=l->geom.y+BLOCKHEIGHT/2+BLOCKHEIGHT;i<l->geom.y+l->geom.h;i+=BLOCKHEIGHT)
checkempty(l->geom.x-BLOCKWIDTH/2,i);
if (!quick2)
for (i=l->geom.y+BLOCKHEIGHT/2+BLOCKHEIGHT;i<l->geom.y+l->geom.h;i+=BLOCKHEIGHT)
checkempty(l->geom.x+BLOCKWIDTH+BLOCKWIDTH/2,i);
break;
case RIGHT:
// falls through
case LEFT:
markgrid(l->geom.x,l->geom.y,l->geom.w,l->geom.h,'-');
SDL_FillRect(screen,&l->geom,SDL_MapRGB(screen->format, 0x00, 0x40, 0x80));
soil(l->geom);
// scan along edges to quickly determine if this
// is going to be complicated.
quick1=true; quick2=true;
for (i=l->geom.x+BLOCKWIDTH/2;i<l->geom.x+l->geom.w;i++)
{
if (grid[i][l->geom.y-1] != ' ' && grid[i][l->geom.y-1] != '*') quick1=false;
if (grid[i][l->geom.y+BLOCKHEIGHT] != ' ' && grid[i][l->geom.y+BLOCKHEIGHT] != '*') quick2=false;
}
checkempty(l->geom.x+BLOCKWIDTH/2,l->geom.y-BLOCKHEIGHT/2);
checkempty(l->geom.x+BLOCKWIDTH/2,l->geom.y+BLOCKHEIGHT+BLOCKHEIGHT/2);
if (!quick1)
for (i=l->geom.x+BLOCKWIDTH/2+BLOCKWIDTH;i<l->geom.x+l->geom.w;i+=BLOCKWIDTH)
checkempty(i,l->geom.y-BLOCKHEIGHT/2);
if (!quick2)
for (i=l->geom.x+BLOCKWIDTH/2+BLOCKWIDTH;i<l->geom.x+l->geom.w;i+=BLOCKWIDTH)
checkempty(i,l->geom.y+BLOCKHEIGHT+BLOCKHEIGHT/2);
break;
}
}
QSet& uniq(QSet& qs) { // doesn't clear qseen! result to be passed to subsetId
SDL_DETERMINIZE_ASSERT(checkempty());
removeShrink(qs, removeDup(seenq));
return qs;
}
