- "blocks" of multiple statements.
- `pass`: a statement which does nothing.
- - expressions: `+`, `-`, `*`, `/` can apply to numbers and `++` can
+ - expressions: `+`, `-`, `*`, `/`, `%` can apply to numbers and `++` can
catenate strings. `and`, `or`, `not` manipulate Booleans, and
normal comparison operators can work on all three types.
- `print`: will print the values in a list of expressions.
}
fmt++;
switch (*fmt) {
- case '%': fputc(*fmt, stderr); break;
- default: fputc('?', stderr); break;
+ case '%': fputc(*fmt, stderr); break; // NOTEST
+ default: fputc('?', stderr); break; // NOTEST
case '1':
type_print(t1, stderr);
break;
else if (type->print_type)
type->print_type(type, f);
else
- fputs("*invalid*type*", f);
+ fputs("*invalid*type*", f); // NOTEST
}
static struct value val_prepare(struct type *type)
if (v.type && v.type->print)
v.type->print(v);
else
- printf("*Unknown*");
+ printf("*Unknown*"); // NOTEST
}
static struct value parse_value(struct type *type, char *arg)
if (type && type->parse)
return type->parse(type, arg);
- rv.type = NULL;
- return rv;
+ rv.type = NULL; // NOTEST
+ return rv; // NOTEST
}
+###### forward decls
+
+ static void free_value(struct value v);
+ static int type_compat(struct type *require, struct type *have, int rules);
+ static void type_print(struct type *type, FILE *f);
+ static struct value val_init(struct type *type);
+ static struct value dup_value(struct value v);
+ static int value_cmp(struct value left, struct value right);
+ static void print_value(struct value v);
+ static struct value parse_value(struct type *type, char *arg);
+
###### free context types
while (context.typelist) {
rv.type = type;
switch(type->vtype) {
- case Vnone:
- break;
+ case Vnone: // NOTEST
+ break; // NOTEST
case Vnum:
mpq_init(rv.num); break;
case Vstr:
case Vbool:
rv.bool = 0;
break;
- case Vlabel:
- rv.label = NULL;
- break;
+ case Vlabel: // NOTEST
+ rv.label = NULL; // NOTEST
+ break; // NOTEST
}
return rv;
}
struct value rv;
rv.type = v.type;
switch (rv.type->vtype) {
- case Vnone:
- break;
+ case Vnone: // NOTEST
+ break; // NOTEST
case Vlabel:
rv.label = v.label;
break;
{
int cmp;
if (left.type != right.type)
- return left.type - right.type;
+ return left.type - right.type; // NOTEST
switch (left.type->vtype) {
case Vlabel: cmp = left.label == right.label ? 0 : 1; break;
case Vnum: cmp = mpq_cmp(left.num, right.num); break;
case Vstr: cmp = text_cmp(left.str, right.str); break;
case Vbool: cmp = left.bool - right.bool; break;
- case Vnone: cmp = 0;
+ case Vnone: cmp = 0; // NOTEST
}
return cmp;
}
static void _print_value(struct value v)
{
switch (v.type->vtype) {
- case Vnone:
- printf("*no-value*"); break;
- case Vlabel:
- printf("*label-%p*", v.label); break;
+ case Vnone: // NOTEST
+ printf("*no-value*"); break; // NOTEST
+ case Vlabel: // NOTEST
+ printf("*label-%p*", v.label); break; // NOTEST
case Vstr:
printf("%.*s", v.str.len, v.str.txt); break;
case Vbool:
val.type = type;
switch(type->vtype) {
- case Vlabel:
- case Vnone:
- val.type = NULL;
- break;
+ case Vlabel: // NOTEST
+ case Vnone: // NOTEST
+ val.type = NULL; // NOTEST
+ break; // NOTEST
case Vstr:
val.str.len = strlen(arg);
val.str.txt = malloc(val.str.len);
static int __fput_loc(struct exec *loc, FILE *f)
{
+ if (!loc)
+ return 0; // NOTEST
if (loc->line >= 0) {
fprintf(f, "%d:%d: ", loc->line, loc->column);
return 1;
static void fput_loc(struct exec *loc, FILE *f)
{
if (!__fput_loc(loc, f))
- fprintf(f, "??:??: ");
+ fprintf(f, "??:??: "); // NOTEST
}
Each different type of `exec` node needs a number of functions
static void print_exec(struct exec *e, int indent, int bracket)
{
if (!e)
- return;
+ return; // NOTEST
switch (e->type) {
case Xbinode:
print_binode(cast(binode, e), indent, bracket); break;
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,
}
} }$
+ $*exec
Variable -> IDENTIFIER ${ {
struct variable *v = var_ref(config2context(config), $1.txt);
$0 = new_pos(var, $1);
v->where_set = $0;
}
}
- $0->var = v;
+ cast(var, $0)->var = v;
} }$
+ ## variable grammar
$*type
Type -> IDENTIFIER ${
$0 = Tnone;
}
}$
+ ## type grammar
###### print exec cases
case Xvar:
struct binding *b = v->var->name;
fprintf(stderr, "%.*s", b->name.len, b->name.txt);
} else
- fputs("???", stderr);
+ fputs("???", stderr); // NOTEST
} else
- fputs("NOTVAR", stderr);
+ fputs("NOTVAR", stderr); // NOTEST
break;
###### propagate exec cases
struct var *var = cast(var, prog);
struct variable *v = var->var;
if (!v) {
- type_err(c, "%d:BUG: no variable!!", prog, Tnone, 0, Tnone);
- *ok = 0;
- return Tnone;
+ type_err(c, "%d:BUG: no variable!!", prog, Tnone, 0, Tnone); // NOTEST
+ *ok = 0; // NOTEST
+ return Tnone; // NOTEST
}
if (v->merged)
v = v->merged;
###### free exec cases
case Xvar: free_var(cast(var, e)); break;
+### Expressions: Conditional
+
+Our first user of the `binode` will be conditional expressions, which
+is a bit odd as they actually have three components. That will be
+handled by having 2 binodes for each expression. The conditional
+expression is the lowest precedence operatior, so it gets to define
+what an "Expression" is. The next level up is "BoolExpr", which
+comes next.
+
+Conditional expressions are of the form "value `if` condition `else`
+other_value". There is no associativite with this operator: the
+values and conditions can only be other conditional expressions if
+they are enclosed in parentheses. Allowing nesting without
+parentheses would be too confusing.
+
+###### Binode types
+ CondExpr,
+
+###### Grammar
+
+ $*exec
+ Expression -> BoolExpr if BoolExpr else BoolExpr ${ {
+ struct binode *b1 = new(binode);
+ struct binode *b2 = new(binode);
+ b1->op = CondExpr;
+ b1->left = $<3;
+ b1->right = b2;
+ b2->op = CondExpr;
+ b2->left = $<1;
+ b2->right = $<5;
+ $0 = b1;
+ } }$
+ | BoolExpr ${ $0 = $<1; }$
+
+###### print binode cases
+
+ case CondExpr:
+ b2 = cast(binode, b->right);
+ print_exec(b2->left, -1, 0);
+ printf(" if ");
+ print_exec(b->left, -1, 0);
+ printf(" else ");
+ print_exec(b2->right, -1, 0);
+ break;
+
+###### propagate binode cases
+
+ case CondExpr: {
+ /* cond must be Tbool, others must match */
+ struct binode *b2 = cast(binode, b->right);
+ struct type *t2;
+
+ propagate_types(b->left, c, ok, Tbool, 0);
+ t = propagate_types(b2->left, c, ok, type, Rnolabel);
+ t2 = propagate_types(b2->right, c, ok, type ?: t, Rnolabel);
+ return t ?: t2;
+ }
+
+###### interp binode cases
+
+ case CondExpr: {
+ struct binode *b2 = cast(binode, b->right);
+ left = interp_exec(b->left);
+ if (left.bool)
+ rv = interp_exec(b2->left);
+ else
+ rv = interp_exec(b2->right);
+ }
+ break;
+
### Expressions: Boolean
-Our first user of the `binode` will be expressions, and particularly
-Boolean expressions. As I haven't implemented precedence in the
-parser generator yet, we need different names for each precedence
-level used by expressions. The outer most or lowest level precedence
-are Boolean `or` `and`, and `not` which form an `Expression` out of `BTerm`s
-and `BFact`s.
+The next class of expressions to use the `binode` will be Boolean
+expressions. As I haven't implemented precedence in the parser
+generator yet, we need different names for each precedence level used
+by expressions. The outer most or lowest level precedence are
+conditional expressions are Boolean operators which form an `BoolExpr`
+out of `BTerm`s and `BFact`s. As well as `or` `and`, and `not` we
+have `and then` and `or else` which only evaluate the second operand
+if the result would make a difference.
###### Binode types
And,
+ AndThen,
Or,
+ OrElse,
Not,
###### Grammar
$*exec
- Expression -> Expression or BTerm ${ {
+ BoolExpr -> BoolExpr or BTerm ${ {
struct binode *b = new(binode);
b->op = Or;
b->left = $<1;
b->right = $<3;
$0 = b;
} }$
+ | BoolExpr or else BTerm ${ {
+ struct binode *b = new(binode);
+ b->op = OrElse;
+ b->left = $<1;
+ b->right = $<4;
+ $0 = b;
+ } }$
| BTerm ${ $0 = $<1; }$
BTerm -> BTerm and BFact ${ {
b->right = $<3;
$0 = b;
} }$
+ | BTerm and then BFact ${ {
+ struct binode *b = new(binode);
+ b->op = AndThen;
+ b->left = $<1;
+ b->right = $<4;
+ $0 = b;
+ } }$
| BFact ${ $0 = $<1; }$
BFact -> not BFact ${ {
printf(" and ");
print_exec(b->right, -1, 0);
break;
+ case AndThen:
+ print_exec(b->left, -1, 0);
+ printf(" and then ");
+ print_exec(b->right, -1, 0);
+ break;
case Or:
print_exec(b->left, -1, 0);
printf(" or ");
print_exec(b->right, -1, 0);
break;
+ case OrElse:
+ print_exec(b->left, -1, 0);
+ printf(" or else ");
+ print_exec(b->right, -1, 0);
+ break;
case Not:
printf("not ");
print_exec(b->right, -1, 0);
###### propagate binode cases
case And:
+ case AndThen:
case Or:
+ case OrElse:
case Not:
/* both must be Tbool, result is Tbool */
propagate_types(b->left, c, ok, Tbool, 0);
right = interp_exec(b->right);
rv.bool = rv.bool && right.bool;
break;
+ case AndThen:
+ rv = interp_exec(b->left);
+ if (rv.bool)
+ rv = interp_exec(b->right);
+ break;
case Or:
rv = interp_exec(b->left);
right = interp_exec(b->right);
rv.bool = rv.bool || right.bool;
break;
+ case OrElse:
+ rv = interp_exec(b->left);
+ if (!rv.bool)
+ rv = interp_exec(b->right);
+ break;
case Not:
rv = interp_exec(b->right);
rv.bool = !rv.bool;
case GtrEq: printf(" >= "); break;
case Eql: printf(" == "); break;
case NEql: printf(" != "); break;
- default: abort();
+ default: abort(); // NOTEST
}
print_exec(b->right, -1, 0);
break;
case GtrEq: rv.bool = cmp >= 0; break;
case Eql: rv.bool = cmp == 0; break;
case NEql: rv.bool = cmp != 0; break;
- default: rv.bool = 0; break;
+ default: rv.bool = 0; break; // NOTEST
}
break;
}
###### Binode types
Plus, Minus,
- Times, Divide,
+ Times, Divide, Rem,
Concat,
Absolute, Negate,
Bracket,
Top -> * ${ $0.op = Times; }$
| / ${ $0.op = Divide; }$
+ | % ${ $0.op = Rem; }$
| ++ ${ $0.op = Concat; }$
###### print binode cases
case Times:
case Divide:
case Concat:
+ case Rem:
print_exec(b->left, indent, 0);
switch(b->op) {
- case Plus: printf(" + "); break;
- case Minus: printf(" - "); break;
- case Times: printf(" * "); break;
- case Divide: printf(" / "); break;
- case Concat: printf(" ++ "); break;
- default: abort();
- }
+ case Plus: fputs(" + ", stdout); break;
+ case Minus: fputs(" - ", stdout); break;
+ case Times: fputs(" * ", stdout); break;
+ case Divide: fputs(" / ", stdout); break;
+ case Rem: fputs(" % ", stdout); break;
+ case Concat: fputs(" ++ ", stdout); break;
+ default: abort(); // NOTEST
+ } // NOTEST
print_exec(b->right, indent, 0);
break;
case Absolute:
case Plus:
case Minus:
case Times:
+ case Rem:
case Divide:
/* both must be numbers, result is Tnum */
case Absolute:
right = interp_exec(b->right);
mpq_div(rv.num, rv.num, right.num);
break;
+ case Rem: {
+ mpz_t l, r, rem;
+
+ left = interp_exec(b->left);
+ right = interp_exec(b->right);
+ mpz_init(l); mpz_init(r); mpz_init(rem);
+ mpz_tdiv_q(l, mpq_numref(left.num), mpq_denref(left.num));
+ mpz_tdiv_q(r, mpq_numref(right.num), mpq_denref(right.num));
+ mpz_tdiv_r(rem, l, r);
+ rv = val_init(Tnum);
+ mpq_set_z(rv.num, rem);
+ mpz_clear(r); mpz_clear(l); mpz_clear(rem);
+ break;
+ }
case Negate:
rv = interp_exec(b->right);
mpq_neg(rv.num, rv.num);
free_value(*lleft);
*lleft = right;
} else
- free_value(right);
+ free_value(right); // NOTEST
right.type = NULL;
break;
break;
###### propagate binode cases
- case Program: abort();
+ case Program: abort(); // NOTEST
###### core functions
int ok = 1;
if (!b)
- return 0;
+ return 0; // NOTEST
do {
ok = 1;
propagate_types(b->right, c, &ok, Tnone, 0);
struct value v;
if (!prog)
- return;
+ return; // NOTEST
al = cast(binode, p->left);
while (al) {
struct var *v = cast(var, al->left);
}
###### interp binode cases
- case Program: abort();
+ case Program: abort(); // NOTEST
## And now to test it out.
a : number
a = A;
b:number = B
- if a > 0 and b > 0:
+ if a > 0 and then b > 0:
while a != b:
if a < b:
b = b - a
print "Yay, I found", target
case GiveUp:
print "Closest I found was", mid
+
+ size::=55
+ list:[size]number
+ list[0] = 1234
+ for i:=1; then i = i + 1; while i < size:
+ n := list[i-1] * list[i-1]
+ list[i] = (n / 100) % 10000
+
+ print "Before sort:"
+ for i:=0; then i = i + 1; while i < size:
+ print "list[",i,"]=",list[i]
+
+ for i := 1; then i=i+1; while i < size:
+ for j:=i-1; then j=j-1; while j >= 0:
+ if list[j] > list[j+1]:
+ t:= list[j]
+ list[j] = list[j+1]
+ list[j+1] = t
+ print "After sort:"
+ for i:=0; then i = i + 1; while i < size:
+ print "list[",i,"]=",list[i]
code / ocean / blobdiff