oceani: allow types to be used before declaration

As we prepare all types after parsing, we can now use a type before it
is declared.
We need to be careful of mutually recursive structures, and
we need to retry prepare_type if it fails because a needed
member hasn't been prepared yet.

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

diff --git a/csrc/oceani-tests.mdc b/csrc/oceani-tests.mdc
index c13a9d173a5f0d876a500791f05fe2630023f073..d1557010e9c03d1cd27b895ace23989ef6227ff0 100644 (file)
--- a/csrc/oceani-tests.mdc
+++ b/csrc/oceani-tests.mdc
@@ -585,6 +585,7 @@ Time to test if structure declarations and accesses work correctly.
        struct foo
                size:[three]number
                name:string
+               thing:baz
                active:Boolean = True
 
        struct baz { a:number; b:Boolean; }
@@ -607,6 +608,7 @@ Time to test if structure declarations and accesses work correctly.
 
                for i:=0; then i=i+1; while i < 4:
                        print info[i].name, info[i].active, info[i].size[0]
+               info[0].thing.b = True
 
 ###### output: structs
 
@@ -776,10 +778,10 @@ separate file first, then run from there.
                This is a multiline string
                With an unsupportable suffix
                """Aa
-       .tmp.code:14:11: error: undefined type: unknown
        .tmp.code:15:12: error: name undeclared: unknowable
        .tmp.code:17:12: error: array size must be a constant: zzsize
        .tmp.code:20:12: error: unrecognised number: 00123
+       .tmp.code:14:11: error: type used but not declared: unknown
 
 ## Tests for type errors
 
@@ -792,7 +794,7 @@ These programs were generated by looking for the
 various places that `type_err()` are called.
 
 ###### test list
-       oceani_failing_tests += type_err1 type_err2 type_err3 type_err4
+       oceani_failing_tests += type_err1 type_err2 type_err3 type_err4 type_err5
 
 ###### test: type_err1
 
@@ -921,6 +923,22 @@ various places that `type_err()` are called.
        .tmp.code:3:14: info: variable 'b' was set as none here.
        oceani: type error in program - not running.
 
+###### test: type_err5
+       struct foo
+               bar:baz
+               a:number
+       struct baz
+               bat:foo
+               b:string
+       struct foo
+               c:number
+
+###### output: type_err5
+       .tmp.code:8:7: error: type already declared: foo
+       .tmp.code:2:7: info: this is location of declartion: foo
+       .tmp.code:2:7: error: type has recursive definition: foo
+       .tmp.code:5:7: error: type has recursive definition: baz
+
 ###### test list
        oceani_failing_tests += type_err_const type_err_const1 type_err_const2 missing_program bad_main
 

diff --git a/csrc/oceani.mdc b/csrc/oceani.mdc
index 9720d222fac37ffced3f0494c446e3af2203eb19..e09fe07a1c22fee614fd2356d9a5bf0e05991553 100644 (file)
--- a/csrc/oceani.mdc
+++ b/csrc/oceani.mdc
@@ -367,6 +367,7 @@ context so indicate that parsing failed.
        static void type_err(struct parse_context *c,
                             char *fmt, struct exec *loc,
                             struct type *t1, int rules, struct type *t2);
+       static void tok_err(struct parse_context *c, char *fmt, struct token *t);
 
 ###### core functions
 
@@ -789,10 +790,11 @@ which might be reported in error messages.
        struct type {
                struct text name;
                struct type *next;
+               struct token first_use;
                int size, align;
                int anon;
                void (*init)(struct type *type, struct value *val);
-               void (*prepare_type)(struct parse_context *c, struct type *type, int parse_time);
+               int (*prepare_type)(struct parse_context *c, struct type *type, int parse_time);
                void (*print)(struct type *type, struct value *val, FILE *f);
                void (*print_type)(struct type *type, FILE *f);
                int (*cmp_order)(struct type *t1, struct type *t2,
@@ -836,7 +838,10 @@ which might be reported in error messages.
                struct type *n;
 
                n = calloc(1, sizeof(*n));
-               *n = *proto;
+               if (proto)
+                       *n = *proto;
+               else
+                       n->size = -1;
                n->name = s;
                n->anon = anon;
                n->next = c->typelist;
@@ -924,10 +929,35 @@ which might be reported in error messages.
        static void prepare_types(struct parse_context *c)
        {
                struct type *t;
+               int retry = 1;
+               enum { none, some, cannot } progress = none;
 
-               for (t = c->typelist; t; t = t->next)
-                       if (t->prepare_type)
-                               t->prepare_type(c, t, 1);
+               while (retry) {
+                       retry = 0;
+
+                       for (t = c->typelist; t; t = t->next) {
+                               if (t->size < 0)
+                                       tok_err(c, "error: type used but not declared",
+                                                &t->first_use);
+                               if (t->size == 0 && t->prepare_type) {
+                                       if (t->prepare_type(c, t, 1))
+                                               progress = some;
+                                       else if (progress == cannot)
+                                               tok_err(c, "error: type has recursive definition",
+                                                       &t->first_use);
+                                       else
+                                               retry = 1;
+                               }
+                       }
+                       switch (progress) {
+                       case cannot:
+                               retry = 0; break;
+                       case none:
+                               progress = cannot; break;
+                       case some:
+                               progress = none; break;
+                       }
+               }
        }
 
 ###### forward decls
@@ -966,12 +996,10 @@ symbol for those.
 
        $*type
        Type -> IDENTIFIER ${
-               $0 = find_type(c, $1.txt);
+               $0 = find_type(c, $ID.txt);
                if (!$0) {
-                       tok_err(c,
-                               "error: undefined type", &$1);
-
-                       $0 = Tnone;
+                       $0 = add_type(c, $ID.txt, NULL);
+                       $0->first_use = $ID;
                }
        }$
        ## type grammar
@@ -2251,33 +2279,37 @@ with a const size by whether they are prepared at parse time or not.
 
 ###### value functions
 
-       static void array_prepare_type(struct parse_context *c, struct type *type,
+       static int array_prepare_type(struct parse_context *c, struct type *type,
                                       int parse_time)
        {
                struct value *vsize;
                mpz_t q;
                if (type->array.static_size)
-                       return;
+                       return 1;       // UNTESTED
                if (type->array.unspec && parse_time)
-                       return;
+                       return 1;       // UNTESTED
                if (parse_time && type->array.vsize && !type->array.vsize->global)
-                       return;
+                       return 1;       // UNTESTED
 
                if (type->array.vsize) {
                        vsize = var_value(c, type->array.vsize);
                        if (!vsize)
-                               return; // UNTESTED
+                               return 1;       // UNTESTED
                        mpz_init(q);
                        mpz_tdiv_q(q, mpq_numref(vsize->num), mpq_denref(vsize->num));
                        type->array.size = mpz_get_si(q);
                        mpz_clear(q);
                }
+               if (!parse_time)
+                       return 1;
+               if (type->array.member->size <= 0)
+                       return 0;
 
-               if (parse_time && type->array.member->size) {
-                       type->array.static_size = 1;
-                       type->size = type->array.size * type->array.member->size;
-                       type->align = type->array.member->align;
-               }
+               type->array.static_size = 1;
+               type->size = type->array.size * type->array.member->size;
+               type->align = type->array.member->align;
+
+               return 1;
        }
 
        static void array_init(struct type *type, struct value *val)
@@ -2606,21 +2638,24 @@ function will be needed.
                free_fieldlist(t->structure.field_list);
        }
 
-       static void structure_prepare_type(struct parse_context *c,
-                                          struct type *t, int parse_time)
+       static int structure_prepare_type(struct parse_context *c,
+                                         struct type *t, int parse_time)
        {
                int cnt = 0;
                struct fieldlist *f;
 
                if (!parse_time || t->structure.fields)
-                       return;
+                       return 1;
 
                for (f = t->structure.field_list; f; f=f->prev) {
                        enum prop_err perr;
                        cnt += 1;
 
+                       if (f->f.type->size <= 0)
+                               return 0;
                        if (f->f.type->prepare_type)
-                               f->f.type->prepare_type(c, f->f.type, 1);
+                               f->f.type->prepare_type(c, f->f.type, parse_time);
+
                        if (f->init == NULL)
                                continue;
                        do {
@@ -2653,6 +2688,7 @@ function will be needed.
 
                        f = f->prev;
                }
+               return 1;
        }
 
        static struct type structure_prototype = {
@@ -2755,9 +2791,23 @@ function will be needed.
 
 ###### top level grammar
        DeclareStruct -> struct IDENTIFIER FieldBlock Newlines ${ {
-               struct type *t =
-                       add_type(c, $2.txt, &structure_prototype);
+               struct type *t;
+               t = find_type(c, $ID.txt);
+               if (!t)
+                       t = add_type(c, $ID.txt, &structure_prototype);
+               else if (t->size >= 0) {
+                       tok_err(c, "error: type already declared", &$ID);
+                       tok_err(c, "info: this is location of declartion", &t->first_use);
+                       /* Create a new one - duplicate */
+                       t = add_type(c, $ID.txt, &structure_prototype);
+               } else {
+                       struct type tmp = *t;
+                       *t = structure_prototype;
+                       t->name = tmp.name;
+                       t->next = tmp.next;
+               }
                t->structure.field_list = $<FB;
+               t->first_use = $ID;
        } }$
 
        $*fieldlist