parsergen: move the 'follow' declaration

[ocean] / csrc / parsergen.mdc

diff --git a/csrc/parsergen.mdc b/csrc/parsergen.mdc
index e0a2167ef1eecf41936c4762d8935bd464190e86..9156c63041121d0ef1f0e34bc7b45932967128b8 100644 (file)
--- a/csrc/parsergen.mdc
+++ b/csrc/parsergen.mdc
@@ -561,6 +561,7 @@ Now we have all the bits we need to parse a full production.
        abort:
                while (tk.num != TK_newline && tk.num != TK_eof)
                        tk = token_next(state);
+               free(p.body);
                return err;
        }
 
@@ -695,7 +696,7 @@ used as a terminal anywhere that a terminal is expected.
                                        s->name.len, s->name.txt);
                        }
                        if (errs) {
-                               free(g);
+                               free(g); // FIXME free content
                                g = NULL;
                        }
                }
@@ -704,7 +705,7 @@ used as a terminal anywhere that a terminal is expected.
                fprintf(stderr, "Error at line %d: %s\n",
                        tk.line, err);
                token_close(state);
-               free(g);
+               free(g); // FIXME free content
                return NULL;
        }
 
@@ -1071,6 +1072,9 @@ and we find the set of possible "first" symbols after there.  This is
 done using `add_first` above and only needs to be done once as the
 "first" sets are now stable and will not change.
 
+###### grammar fields
+       struct symset *follow;
+
 ###### follow code
 
        for (p = 0; p < g->production_count; p++) {
@@ -1097,10 +1101,10 @@ combine these two functions into a single loop.
 
 ###### follow code
 
-       for (again = 0, p = 0;
+       for (check_again = 0, p = 0;
             p < g->production_count;
             p < g->production_count-1
-               ? p++ : again ? (again = 0, p = 0)
+               ? p++ : check_again ? (check_again = 0, p = 0)
                              : p++) {
                struct production *pr = g->productions[p];
                int b;
@@ -1111,7 +1115,7 @@ combine these two functions into a single loop.
                                break;
                        if (symset_union(&g->follow[bs->num],
                                         &g->follow[pr->head->num]))
-                               again = 1;
+                               check_again = 1;
                        if (!bs->nullable)
                                break;
                }
@@ -1120,13 +1124,10 @@ combine these two functions into a single loop.
 We now just need to create and initialise the `follow` list to get a
 complete function.
 
-###### grammar fields
-       struct symset *follow;
-
 ###### functions
        static void build_follow(struct grammar *g)
        {
-               int s, again, p;
+               int s, check_again, p;
                g->follow = calloc(g->num_syms, sizeof(g->follow[0]));
                for (s = 0; s < g->num_syms; s++)
                        g->follow[s] = INIT_SYMSET;
@@ -1407,7 +1408,7 @@ so the item is ineffective.
                        continue;
                if (s->line_like)
                        is->starts_line = 1;
-               again = 1;
+               check_again = 1;
                if (type >= LALR) {
                        // Need the LA set.
                        int to_end;
@@ -1527,7 +1528,7 @@ with `TK_eof` as the LA set.
        {
                struct symset first = INIT_SYMSET;
                struct itemset *is;
-               int again;
+               int check_again;
                unsigned short la = 0;
                if (type >= LALR) {
                        // LA set just has eof
@@ -1539,15 +1540,15 @@ with `TK_eof` as the LA set.
                // production 0, offset 0 (with no data)
                symset_add(&first, item_num(0, 0), la);
                add_itemset(g, first, Non, 0, type);
-               for (again = 0, is = g->items;
+               for (check_again = 0, is = g->items;
                     is;
-                    is = is->next ?: again ? (again = 0, g->items) : NULL) {
+                    is = is->next ?: check_again ? (check_again = 0, g->items) : NULL) {
                        int i;
                        struct symset done = INIT_SYMSET;
                        if (is->completed)
                                continue;
                        is->completed = 1;
-                       again = 1;
+                       check_again = 1;
                        ## complete itemset
                        ## derive itemsets
                        symset_free(done);
@@ -2072,8 +2073,6 @@ The go to table is stored in a simple array of `sym` and corresponding
                }
        }
 
-###### functions
-
        static void gen_states(FILE *f, struct grammar *g)
        {
                int i;
@@ -2661,6 +2660,35 @@ table.
                        return -1;
        }
 
+### Memory allocation
+
+The `scanner` returns tokens in a local variable - we want them in allocated
+memory so they can live in the `asn_stack`.  Similarly the `asn` produced by
+a reduce is in a large buffer.  Both of these require some allocation and
+copying, hence `memdup` and `tok_copy`.
+
+###### parser includes
+       #include <memory.h>
+
+###### parser functions
+
+       void *memdup(void *m, int len)
+       {
+               void *ret;
+               if (len == 0)
+                       return NULL;
+               ret = malloc(len);
+               memcpy(ret, m, len);
+               return ret;
+       }
+
+       static struct token *tok_copy(struct token tk)
+       {
+               struct token *new = malloc(sizeof(*new));
+               *new = tk;
+               return new;
+       }
+
 ### The state stack.
 
 The core data structure for the parser is the stack.  This tracks all
@@ -2833,35 +2861,6 @@ before we `shift` the nonterminal in.
                return indents;
        }
 
-### Memory allocation
-
-The `scanner` returns tokens in a local variable - we want them in allocated
-memory so they can live in the `asn_stack`.  Similarly the `asn` produced by
-a reduce is in a large buffer.  Both of these require some allocation and
-copying, hence `memdup` and `tokcopy`.
-
-###### parser includes
-       #include <memory.h>
-
-###### parser functions
-
-       void *memdup(void *m, int len)
-       {
-               void *ret;
-               if (len == 0)
-                       return NULL;
-               ret = malloc(len);
-               memcpy(ret, m, len);
-               return ret;
-       }
-
-       static struct token *tok_copy(struct token tk)
-       {
-               struct token *new = malloc(sizeof(*new));
-               *new = tk;
-               return new;
-       }
-
 ### The heart of the parser.
 
 Now we have the parser.  For each token we might shift it, trigger a