return ret;
}
+### Complex types
+
+Now that we have the shape of the interpreter in place we can add some
+complex types and connected them in to the data structures and the
+different phases of parse, analyse, print, interpret.
+
+For now, just arrays.
+
+#### Arrays
+
+Arrays can be declared by giving a size and a type, as `[size]type' so
+`freq:[26]number` declares `freq` to be an array of 26 numbers. The
+size can be an arbitrary expression which is evaluated when the name
+comes into scope.
+
+Arrays cannot be assigned. When pointers are introduced we will also
+introduce array slices which can refer to part or all of an array -
+the assignment syntax will create a slice. For now, an array can only
+ever be referenced by the name it is declared with. It is likely that
+a "`copy`" primitive will eventually be define which can be used to
+make a copy of an array with controllable depth.
+
+###### type union fields
+
+ struct {
+ int size;
+ struct variable *vsize;
+ struct type *member;
+ } array;
+
+###### value union fields
+ struct {
+ struct value *elmnts;
+ } array;
+
+###### value functions
+
+ static struct value array_prepare(struct type *type)
+ {
+ struct value ret;
+
+ ret.type = type;
+ ret.array.elmnts = NULL;
+ return ret;
+ }
+
+ static struct value array_init(struct type *type)
+ {
+ struct value ret;
+ int i;
+
+ ret.type = type;
+ if (type->array.vsize) {
+ mpz_t q;
+ mpz_init(q);
+ mpz_tdiv_q(q, mpq_numref(type->array.vsize->val.num),
+ mpq_denref(type->array.vsize->val.num));
+ type->array.size = mpz_get_si(q);
+ mpz_clear(q);
+ }
+ ret.array.elmnts = calloc(type->array.size,
+ sizeof(ret.array.elmnts[0]));
+ for (i = 0; ret.array.elmnts && i < type->array.size; i++)
+ ret.array.elmnts[i] = val_init(type->array.member);
+ return ret;
+ }
+
+ static void array_free(struct value val)
+ {
+ int i;
+
+ if (val.array.elmnts)
+ for (i = 0; i < val.type->array.size; i++)
+ free_value(val.array.elmnts[i]);
+ free(val.array.elmnts);
+ }
+
+ static int array_compat(struct type *require, struct type *have)
+ {
+ if (have->compat != require->compat)
+ return 0;
+ /* Both are arrays, so we can look at details */
+ if (!type_compat(require->array.member, have->array.member, 0))
+ return 0;
+ if (require->array.vsize == NULL && have->array.vsize == NULL)
+ return require->array.size == have->array.size;
+
+ return require->array.vsize == have->array.vsize;
+ }
+
+ static void array_print_type(struct type *type, FILE *f)
+ {
+ fputs("[", f);
+ if (type->array.vsize) {
+ struct binding *b = type->array.vsize->name;
+ fprintf(f, "%.*s]", b->name.len, b->name.txt);
+ } else
+ fprintf(f, "%d]", type->array.size);
+ type_print(type->array.member, f);
+ }
+
+ static struct type array_prototype = {
+ .prepare = array_prepare,
+ .init = array_init,
+ .print_type = array_print_type,
+ .compat = array_compat,
+ .free = array_free,
+ };
+
+###### type grammar
+
+ | [ NUMBER ] Type ${
+ $0 = calloc(1, sizeof(struct type));
+ *($0) = array_prototype;
+ $0->array.member = $<4;
+ $0->array.vsize = NULL;
+ {
+ struct parse_context *c = config2context(config);
+ char tail[3];
+ mpq_t num;
+ if (number_parse(num, tail, $2.txt) == 0)
+ tok_err(c, "error: unrecognised number", &$2);
+ else if (tail[0])
+ tok_err(c, "error: unsupported number suffix", &$2);
+ else {
+ $0->array.size = mpz_get_ui(mpq_numref(num));
+ if (mpz_cmp_ui(mpq_denref(num), 1) != 0) {
+ tok_err(c, "error: array size must be an integer",
+ &$2);
+ } else if (mpz_cmp_ui(mpq_numref(num), 1UL << 30) >= 0)
+ tok_err(c, "error: array size is too large",
+ &$2);
+ mpq_clear(num);
+ }
+ $0->next= c->anon_typelist;
+ c->anon_typelist = $0;
+ }
+ }$
+
+ | [ IDENTIFIER ] Type ${ {
+ struct parse_context *c = config2context(config);
+ struct variable *v = var_ref(c, $2.txt);
+
+ if (!v)
+ tok_err(config2context(config), "error: name undeclared", &$2);
+ else if (!v->constant)
+ tok_err(config2context(config), "error: array size must be a constant", &$2);
+
+ $0 = calloc(1, sizeof(struct type));
+ *($0) = array_prototype;
+ $0->array.member = $<4;
+ $0->array.size = 0;
+ $0->array.vsize = v;
+ $0->next= c->anon_typelist;
+ c->anon_typelist = $0;
+ } }$
+
+###### parse context
+
+ struct type *anon_typelist;
+
+###### free context types
+
+ while (context.anon_typelist) {
+ struct type *t = context.anon_typelist;
+
+ context.anon_typelist = t->next;
+ free(t);
+ }
+
+###### Binode types
+ Index,
+
+###### variable grammar
+
+ | Variable [ Expression ] ${ {
+ struct binode *b = new(binode);
+ b->op = Index;
+ b->left = $<1;
+ b->right = $<3;
+ $0 = b;
+ } }$
+
+###### print binode cases
+ case Index:
+ print_exec(b->left, -1, 0);
+ printf("[");
+ print_exec(b->right, -1, 0);
+ printf("]");
+ break;
+
+###### propagate binode cases
+ case Index:
+ /* left must be an array, right must be a number,
+ * result is the member type of the array
+ */
+ propagate_types(b->right, c, ok, Tnum, 0);
+ t = propagate_types(b->left, c, ok, NULL, rules & Rnoconstant);
+ if (!t || t->compat != array_compat) {
+ type_err(c, "error: %1 cannot be indexed", prog, t, 0, NULL);
+ *ok = 0;
+ return NULL;
+ } else {
+ if (!type_compat(type, t->array.member, rules)) {
+ type_err(c, "error: have %1 but need %2", prog,
+ t->array.member, rules, type);
+ *ok = 0;
+ }
+ return t->array.member;
+ }
+ break;
+
+###### interp binode cases
+ case Index: {
+ mpz_t q;
+ long i;
+
+ lleft = linterp_exec(b->left);
+ right = interp_exec(b->right);
+ mpz_init(q);
+ mpz_tdiv_q(q, mpq_numref(right.num), mpq_denref(right.num));
+ i = mpz_get_si(q);
+ mpz_clear(q);
+
+ if (i >= 0 && i < lleft->type->array.size)
+ lrv = &lleft->array.elmnts[i];
+ else
+ rv = val_init(lleft->type->array.member);
+ break;
+ }
+
## Language elements
Each language element needs to be parsed, printed, analysed,
break;
}
-## Complex types
-
-Now that we have the shape of the interpreter in place we can add some
-complex types and connected them in to the data structures and the
-different phases of parse, analyse, print, interpret.
-
-For now, just arrays.
-
-### Arrays
-
-Arrays can be declared by giving a size and a type, as `[size]type' so
-`freq:[26]number` declares `freq` to be an array of 26 numbers. The
-size can be an arbitrary expression which is evaluated when the name
-comes into scope.
-
-Arrays cannot be assigned. When pointers are introduced we will also
-introduce array slices which can refer to part or all of an array -
-the assignment syntax will create a slice. For now, an array can only
-ever be referenced by the name it is declared with. It is likely that
-a "`copy`" primitive will eventually be define which can be used to
-make a copy of an array with controllable depth.
-
-###### type union fields
-
- struct {
- int size;
- struct variable *vsize;
- struct type *member;
- } array;
-
-###### value union fields
- struct {
- struct value *elmnts;
- } array;
-
-###### value functions
-
- static struct value array_prepare(struct type *type)
- {
- struct value ret;
-
- ret.type = type;
- ret.array.elmnts = NULL;
- return ret;
- }
-
- static struct value array_init(struct type *type)
- {
- struct value ret;
- int i;
-
- ret.type = type;
- if (type->array.vsize) {
- mpz_t q;
- mpz_init(q);
- mpz_tdiv_q(q, mpq_numref(type->array.vsize->val.num),
- mpq_denref(type->array.vsize->val.num));
- type->array.size = mpz_get_si(q);
- mpz_clear(q);
- }
- ret.array.elmnts = calloc(type->array.size,
- sizeof(ret.array.elmnts[0]));
- for (i = 0; ret.array.elmnts && i < type->array.size; i++)
- ret.array.elmnts[i] = val_init(type->array.member);
- return ret;
- }
-
- static void array_free(struct value val)
- {
- int i;
-
- if (val.array.elmnts)
- for (i = 0; i < val.type->array.size; i++)
- free_value(val.array.elmnts[i]);
- free(val.array.elmnts);
- }
-
- static int array_compat(struct type *require, struct type *have)
- {
- if (have->compat != require->compat)
- return 0;
- /* Both are arrays, so we can look at details */
- if (!type_compat(require->array.member, have->array.member, 0))
- return 0;
- if (require->array.vsize == NULL && have->array.vsize == NULL)
- return require->array.size == have->array.size;
-
- return require->array.vsize == have->array.vsize;
- }
-
- static void array_print_type(struct type *type, FILE *f)
- {
- fputs("[", f);
- if (type->array.vsize) {
- struct binding *b = type->array.vsize->name;
- fprintf(f, "%.*s]", b->name.len, b->name.txt);
- } else
- fprintf(f, "%d]", type->array.size);
- type_print(type->array.member, f);
- }
-
- static struct type array_prototype = {
- .prepare = array_prepare,
- .init = array_init,
- .print_type = array_print_type,
- .compat = array_compat,
- .free = array_free,
- };
-
-###### type grammar
-
- | [ NUMBER ] Type ${
- $0 = calloc(1, sizeof(struct type));
- *($0) = array_prototype;
- $0->array.member = $<4;
- $0->array.vsize = NULL;
- {
- struct parse_context *c = config2context(config);
- char tail[3];
- mpq_t num;
- if (number_parse(num, tail, $2.txt) == 0)
- tok_err(c, "error: unrecognised number", &$2);
- else if (tail[0])
- tok_err(c, "error: unsupported number suffix", &$2);
- else {
- $0->array.size = mpz_get_ui(mpq_numref(num));
- if (mpz_cmp_ui(mpq_denref(num), 1) != 0) {
- tok_err(c, "error: array size must be an integer",
- &$2);
- } else if (mpz_cmp_ui(mpq_numref(num), 1UL << 30) >= 0)
- tok_err(c, "error: array size is too large",
- &$2);
- mpq_clear(num);
- }
- $0->next= c->anon_typelist;
- c->anon_typelist = $0;
- }
- }$
-
- | [ IDENTIFIER ] Type ${ {
- struct parse_context *c = config2context(config);
- struct variable *v = var_ref(c, $2.txt);
-
- if (!v)
- tok_err(config2context(config), "error: name undeclared", &$2);
- else if (!v->constant)
- tok_err(config2context(config), "error: array size must be a constant", &$2);
-
- $0 = calloc(1, sizeof(struct type));
- *($0) = array_prototype;
- $0->array.member = $<4;
- $0->array.size = 0;
- $0->array.vsize = v;
- $0->next= c->anon_typelist;
- c->anon_typelist = $0;
- } }$
-
-###### parse context
-
- struct type *anon_typelist;
-
-###### free context types
-
- while (context.anon_typelist) {
- struct type *t = context.anon_typelist;
-
- context.anon_typelist = t->next;
- free(t);
- }
-
-###### Binode types
- Index,
-
-###### variable grammar
-
- | Variable [ Expression ] ${ {
- struct binode *b = new(binode);
- b->op = Index;
- b->left = $<1;
- b->right = $<3;
- $0 = b;
- } }$
-
-###### print binode cases
- case Index:
- print_exec(b->left, -1, 0);
- printf("[");
- print_exec(b->right, -1, 0);
- printf("]");
- break;
-
-###### propagate binode cases
- case Index:
- /* left must be an array, right must be a number,
- * result is the member type of the array
- */
- propagate_types(b->right, c, ok, Tnum, 0);
- t = propagate_types(b->left, c, ok, NULL, rules & Rnoconstant);
- if (!t || t->compat != array_compat) {
- type_err(c, "error: %1 cannot be indexed", prog, t, 0, NULL);
- *ok = 0;
- return NULL;
- } else {
- if (!type_compat(type, t->array.member, rules)) {
- type_err(c, "error: have %1 but need %2", prog,
- t->array.member, rules, type);
- *ok = 0;
- }
- return t->array.member;
- }
- break;
-
-###### interp binode cases
- case Index: {
- mpz_t q;
- long i;
-
- lleft = linterp_exec(b->left);
- right = interp_exec(b->right);
- mpz_init(q);
- mpz_tdiv_q(q, mpq_numref(right.num), mpq_denref(right.num));
- i = mpz_get_si(q);
- mpz_clear(q);
-
- if (i >= 0 && i < lleft->type->array.size)
- lrv = &lleft->array.elmnts[i];
- else
- rv = val_init(lleft->type->array.member);
- break;
- }
-
### Finally the whole program.
Somewhat reminiscent of Pascal a (current) Ocean program starts with
code / ocean / commitdiff