parsergen: calculate and record "min_prefix" for each state.

This is needed to determine when we can cancel an TK_out.

Signed-off-by: NeilBrown <neil@brown.name>

diff --git a/csrc/parsergen.mdc b/csrc/parsergen.mdc
index 573f6def52c12c3889fdcc97eab140850b884dac..45fb09e5228f26ce3240a8daa46f1d6d092ffa7d 100644 (file)
--- a/csrc/parsergen.mdc
+++ b/csrc/parsergen.mdc
@@ -1178,6 +1178,7 @@ should happen, so we don't need to search a second time.
                struct symset go_to;
                char completed;
                char starts_line;
+               int min_prefix;
        };
 
 ###### grammar fields
@@ -1284,6 +1285,9 @@ though.
                struct symset LA = INIT_SYMSET;
                unsigned short sn = 0;
 
+               if (is->min_prefix == 0 ||
+                   (bs > 0 && bs < is->min_prefix))
+                       is->min_prefix = bs;
                if (bs == pr->body_size)
                        continue;
                s = pr->body[bs];
@@ -1629,7 +1633,8 @@ Now we can report all the item sets complete with items, LA sets, and GO TO.
                for (s = 0; s < g->states; s++) {
                        int j;
                        struct itemset *is = g->statetab[s];
-                       printf("  Itemset %d:%s\n", s, is->starts_line?" (startsline)":"");
+                       printf("  Itemset %d:%s min prefix=%d\n",
+                              s, is->starts_line?" (startsline)":"", is->min_prefix);
                        for (j = 0; j < is->items.cnt; j++) {
                                report_item(g, is->items.syms[j]);
                                if (is->items.data != NO_DATA)
@@ -1893,6 +1898,7 @@ The go to table is stored in a simple array of `sym` and corresponding
                short reduce_sym;
                short shift_sym;
                short starts_line;
+               short min_prefix;
        };
 
 
@@ -1949,15 +1955,15 @@ The go to table is stored in a simple array of `sym` and corresponding
                        }
 
                        if (prod >= 0)
-                               fprintf(f, "\t[%d] = { %d, goto_%d, %d, %d, %d, 0, %d },\n",
+                               fprintf(f, "\t[%d] = { %d, goto_%d, %d, %d, %d, 0, %d, %d },\n",
                                        i, is->go_to.cnt, i, prod,
                                        g->productions[prod]->body_size,
                                        g->productions[prod]->head->num,
-                                       is->starts_line);
+                                       is->starts_line, is->min_prefix);
                        else
-                               fprintf(f, "\t[%d] = { %d, goto_%d, -1, -1, -1, %d, %d },\n",
+                               fprintf(f, "\t[%d] = { %d, goto_%d, -1, -1, -1, %d, %d, %d },\n",
                                        i, is->go_to.cnt, i, shift_sym,
-                                       is->starts_line);
+                                       is->starts_line, is->min_prefix);
                }
                fprintf(f, "};\n\n");
        }