parsergen: allow $<1 to be used for structs as well as pointer.

[ocean] / csrc / parsergen.mdc

diff --git a/csrc/parsergen.mdc b/csrc/parsergen.mdc
index d2ff89844d2e616e0f10e470c0a7dbffde9492a7..d30275e4e4d383a22905acd1e415c72d89fc56de 100644 (file)
--- a/csrc/parsergen.mdc
+++ b/csrc/parsergen.mdc
@@ -277,6 +277,9 @@ declares how it associates.  This level is stored in each symbol
 listed and may be inherited by any production which uses the symbol.  A
 production inherits from the last symbol which has a precedence.
 
+The symbols on the first precedence line have the lowest precedence.
+Subsequent lines introduce symbols with higher precedence.
+
 ###### grammar fields
        struct text current_type;
        int type_isref;
@@ -1287,12 +1290,11 @@ When itemsets are created we assign a precedence to the itemset from
 the complete item, if there is one.  We ignore the possibility of
 there being two and don't (currently) handle precedence in such
 grammars.  When completing a grammar we ignore any item where DOT is
-followed by a terminal with a precedence lower (numerically higher)
-than that for the itemset.  Unless the terminal has right
-associativity, we also ignore items where the terminal has the same
-precedence.  The result is that unwanted items are still in the
-itemset, but the terminal doesn't get into the go to set, so the item
-is ineffective.
+followed by a terminal with a precedence lower than that for the
+itemset.  Unless the terminal has right associativity, we also ignore
+items where the terminal has the same precedence.  The result is that
+unwanted items are still in the itemset, but the terminal doesn't get
+into the go to set, so the item is ineffective.
 
 ###### complete itemset
        for (i = 0; i < is->items.cnt; i++) {
@@ -1311,7 +1313,7 @@ is ineffective.
                        continue;
                s = pr->body[bs];
                if (s->precedence && is->precedence &&
-                   is->precedence < s->precedence)
+                   is->precedence > s->precedence)
                        /* This terminal has a low precedence and
                         * shouldn't be shifted
                         */
@@ -1404,8 +1406,7 @@ with a pre-existing itemset).
                        pos = symset_find(&newitemset, pr->head->num);
                        if (bp + 1 == pr->body_size &&
                            pr->precedence > 0 &&
-                           (precedence == 0 ||
-                            pr->precedence < precedence)) {
+                           pr->precedence > precedence) {
                                // new itemset is reducible and has a precedence.
                                precedence = pr->precedence;
                                assoc = pr->assoc;
@@ -1799,14 +1800,20 @@ counted, and are reported as non-critical.  This will not affect a
                                int p = item_prod(itm);
                                int bp = item_index(itm);
                                struct production *pr = g->productions[p];
+                               struct symbol *s;
 
-                               if (bp < pr->body_size &&
-                                   pr->body[bp]->type == Terminal) {
-                                       /* shiftable */
-                                       int sym = pr->body[bp]->num;
-                                       if (symset_find(&shifts, sym) < 0)
-                                               symset_add(&shifts, sym, itm);
-                               }
+                               if (bp >= pr->body_size ||
+                                   pr->body[bp]->type != Terminal)
+                                       /* not shiftable */
+                                       continue;
+
+                               s = pr->body[bp];
+                               if (s->precedence && is->precedence)
+                                       /* Precedence resolves this, so no conflict */
+                                       continue;
+
+                               if (symset_find(&shifts, s->num) < 0)
+                                       symset_add(&shifts, s->num, itm);
                        }
                        /* Now look for reductions and conflicts */
                        for (j = 0; j < is->items.cnt; j++) {
@@ -2105,10 +2112,13 @@ automatically freed.  This is equivalent to assigning `NULL` to the pointer.
                fputs("\n", f);
                for (i = 0; i < p->body_size; i++) {
                        if (p->body[i]->struct_name.txt &&
-                           p->body[i]->isref &&
-                           used[i])
+                           used[i]) {
                                // assume this has been copied out
-                               fprintf(f, "\t\t*(void**)body[%d] = NULL;\n", i);
+                               if (p->body[i]->isref)
+                                       fprintf(f, "\t\t*(void**)body[%d] = NULL;\n", i);
+                               else
+                                       fprintf(f, "\t\tmemset(body[%d], 0, sizeof(struct %.*s));\n", i, p->body[i]->struct_name.len, p->body[i]->struct_name.txt);
+                       }
                }
                free(used);
        }
@@ -3089,8 +3099,8 @@ an error.
 
 # calc: grammar
 
-       $LEFT * /
        $LEFT + -
+       $LEFT * /
 
        Session -> Session Line
                | Line