]> ocean-lang.org Git - ocean/blobdiff - csrc/oceani.mdc
oceani: don't let error in one statement hides errors in next.
[ocean] / csrc / oceani.mdc
index e147baa1303ed29643c8f4b43c0c5c0bebd04fb8..f97652d025ca4c90ef8e183ac45bea0eed41a677 100644 (file)
@@ -37,9 +37,9 @@ boolean operators.
 
 Some operators that have only recently been added, and so have not
 generated all that much experience yet are "and then" and "or else" as
-short-circuit Boolean operators, and the "if ... else" trinary
-operator which can select between two expressions based on a third
-(which appears syntactically in the middle).
+short-circuit Boolean operators (which have since been remove), and the
+"if ...  else" trinary operator which can select between two expressions
+based on a third (which appears syntactically in the middle).
 
 The "func" clause currently only allows a "main" function to be
 declared.  That will be extended when proper function support is added.
@@ -367,14 +367,14 @@ context so indicate that parsing failed.
        static void fput_loc(struct exec *loc, FILE *f);
        static void type_err(struct parse_context *c,
                             char *fmt, struct exec *loc,
-                            struct type *t1, int rules, struct type *t2);
+                            struct type *t1, enum val_rules rules, struct type *t2);
        static void tok_err(struct parse_context *c, char *fmt, struct token *t);
 
 ###### core functions
 
        static void type_err(struct parse_context *c,
                             char *fmt, struct exec *loc,
-                            struct type *t1, int rules, struct type *t2)
+                            struct type *t1, enum val_rules rules, struct type *t2)
        {
                fprintf(stderr, "%s:", c->file_name);
                fput_loc(loc, stderr);
@@ -589,30 +589,27 @@ expected to return, and returns the type that it does return, either of
 which can be `NULL` signifying "unknown".  A `prop_err` flag set is
 passed by reference.  It has `Efail` set when an error is found, and
 `Eretry` when the type for some element is set via propagation.  If
-any expression cannot be evaluated immediately, `Enoconst` is set.
+any expression cannot be evaluated a compile time, `Eruntime` is set.
 If the expression can be copied, `Emaycopy` is set.
 
-If it remains unchanged at `0`, then no more propagation is needed.
+If `Erval` is set, then the value cannot be assigned to because it is
+a temporary result.  If `Erval` is clear but `Econst` is set, then
+the value can only be assigned once, when the variable is declared.
 
 ###### ast
 
-       enum val_rules {Rnolabel = 1<<0, Rboolok = 1<<1, Rnoconstant = 1<<2};
-       enum prop_err {Efail = 1<<0, Eretry = 1<<1, Enoconst = 1<<2,
-                      Emaycopy = 1<<3};
-
-###### format cases
-       case 'r':
-               if (rules & Rnolabel)
-                       fputs(" (labels not permitted)", stderr);
-               break;
+       enum val_rules {Rboolok = 1<<0, Rrefok = 1<<1,};
+       enum prop_err {Efail = 1<<0, Eretry = 1<<1, Eruntime = 1<<2,
+                      Emaycopy = 1<<3, Erval = 1<<4, Econst = 1<<5};
 
 ###### forward decls
        static struct type *propagate_types(struct exec *prog, struct parse_context *c, enum prop_err *perr,
-                                           struct type *type, int rules);
+                                           struct type *type, enum val_rules rules);
 ###### core functions
 
        static struct type *__propagate_types(struct exec *prog, struct parse_context *c, enum prop_err *perr,
-                                             struct type *type, int rules)
+                                             enum prop_err *perr_local,
+                                             struct type *type, enum val_rules rules)
        {
                struct type *t;
 
@@ -634,11 +631,13 @@ If it remains unchanged at `0`, then no more propagation is needed.
        }
 
        static struct type *propagate_types(struct exec *prog, struct parse_context *c, enum prop_err *perr,
-                                           struct type *type, int rules)
+                                           struct type *type, enum val_rules rules)
        {
                int pre_err = c->parse_error;
-               struct type *ret = __propagate_types(prog, c, perr, type, rules);
+               enum prop_err perr_local = 0;
+               struct type *ret = __propagate_types(prog, c, perr, &perr_local, type, rules);
 
+               *perr |= perr_local & (Efail | Eretry);
                if (c->parse_error > pre_err)
                        *perr |= Efail;
                return ret;
@@ -992,7 +991,7 @@ which might be reported in error messages.
 ###### forward decls
 
        static void free_value(struct type *type, struct value *v);
-       static int type_compat(struct type *require, struct type *have, int rules);
+       static int type_compat(struct type *require, struct type *have, enum val_rules rules);
        static void type_print(struct type *type, FILE *f);
        static void val_init(struct type *type, struct value *v);
        static void dup_value(struct type *type,
@@ -1057,21 +1056,20 @@ A separate function encoding these cases will simplify some code later.
 
 ###### type functions
 
-       int (*compat)(struct type *this, struct type *other);
+       int (*compat)(struct type *this, struct type *other, enum val_rules rules);
 
 ###### ast functions
 
-       static int type_compat(struct type *require, struct type *have, int rules)
+       static int type_compat(struct type *require, struct type *have,
+                              enum val_rules rules)
        {
                if ((rules & Rboolok) && have == Tbool)
                        return 1;       // NOTEST
-               if ((rules & Rnolabel) && have == Tlabel)
-                       return 0;       // NOTEST
                if (!require || !have)
                        return 1;
 
                if (require->compat)
-                       return require->compat(require, have);
+                       return require->compat(require, have, rules);
 
                return require == have;
        }
@@ -1159,7 +1157,7 @@ A separate function encoding these cases will simplify some code later.
        {
                int cmp;
                if (tl != tr)
-                       return tl - tr; // NOTEST
+                       return tl - tr;
                switch (tl->vtype) {
                case Vlabel: cmp = left->label == right->label ? 0 : 1; break;
                case Vnum: cmp = mpq_cmp(left->num, right->num); break;
@@ -1276,13 +1274,13 @@ executable.
                $0->val.bool = 0;
        }$
        | NUMBER ${ {
-               char tail[3];
+               char tail[3] = "";
                $0 = new_val(Tnum, $1);
-               if (number_parse($0->val.num, tail, $1.txt) == 0)
-                       mpq_init($0->val.num);  // UNTESTED
-                       if (tail[0])
-                               tok_err(c, "error: unsupported number suffix",
-                                       &$1);
+               if (number_parse($0->val.num, tail, $1.txt) == 0) {
+                       mpq_init($0->val.num);
+                       tok_err(c, "error: unsupported number format", &$NUM);
+               } else if (tail[0])
+                       tok_err(c, "error: unsupported number suffix", &$1);
        } }$
        | STRING ${ {
                char tail[3];
@@ -1319,8 +1317,9 @@ executable.
        {
                struct val *val = cast(val, prog);
                if (!type_compat(type, val->vtype, rules))
-                       type_err(c, "error: expected %1%r found %2",
+                       type_err(c, "error: expected %1 found %2",
                                   prog, type, rules, val->vtype);
+               *perr |= Erval;
                return val->vtype;
        }
 
@@ -1441,8 +1440,9 @@ match "case".
                struct label *l = cast(label, prog);
                l->value = label_lookup(c, l->name);
                if (!type_compat(type, Tlabel, rules))
-                       type_err(c, "error: expected %1%r found %2",
+                       type_err(c, "error: expected %1 found %2",
                                 prog, type, rules, Tlabel);
+               *perr |= Erval;
                return Tlabel;
        }
 ###### interp exec cases
@@ -2023,7 +2023,7 @@ tell if it was set or not later.
        {
                if (!v->global) {
                        if (!c->local || !v->type)
-                               return NULL;    // UNTESTED
+                               return NULL;    // NOTEST
                        if (v->frame_pos + v->type->size > c->local_size) {
                                printf("INVALID frame_pos\n");  // NOTEST
                                exit(2);                        // NOTEST
@@ -2049,7 +2049,7 @@ tell if it was set or not later.
                        t->prepare_type(c, t, 1);       // NOTEST
 
                if (c->global_size & (t->align - 1))
-                       c->global_size = (c->global_size + t->align) & ~(t->align-1);   // NOTEST
+                       c->global_size = (c->global_size + t->align) & ~(t->align-1);
                if (!v) {
                        v = &scratch;
                        v->type = t;
@@ -2096,7 +2096,7 @@ stack.
                        if (v->merged != v)
                                continue;
                        if (!t)
-                               continue;
+                               continue;       // NOTEST
                        if (v->frame_pos >= 0)
                                continue;
                        while (done && done->scope_end < v->scope_start)
@@ -2274,13 +2274,6 @@ correctly.
                        return Tnone;                                   // NOTEST
                }
                v = v->merged;
-               if (v->constant && (rules & Rnoconstant)) {
-                       type_err(c, "error: Cannot assign to a constant: %v",
-                                prog, NULL, 0, NULL);
-                       type_err(c, "info: name was defined as a constant here",
-                                v->where_decl, NULL, 0, NULL);
-                       return v->type;
-               }
                if (v->type == Tnone && v->where_decl == prog)
                        type_err(c, "error: variable used but not declared: %v",
                                 prog, NULL, 0, NULL);
@@ -2291,16 +2284,16 @@ correctly.
                                *perr |= Eretry;
                        }
                } else if (!type_compat(type, v->type, rules)) {
-                       type_err(c, "error: expected %1%r but variable '%v' is %2", prog,
+                       type_err(c, "error: expected %1 but variable '%v' is %2", prog,
                                 type, rules, v->type);
                        type_err(c, "info: this is where '%v' was set to %1", v->where_set,
                                 v->type, rules, NULL);
                }
                if (!v->global || v->frame_pos < 0)
-                       *perr |= Enoconst;
-               if (!type)
-                       return v->type;
-               return type;
+                       *perr |= Eruntime;
+               if (v->constant)
+                       *perr |= Econst;
+               return v->type;
        }
 
 ###### interp exec cases
@@ -2405,16 +2398,16 @@ with a const size by whether they are prepared at parse time or not.
                struct value *vsize;
                mpz_t q;
                if (type->array.static_size)
-                       return 1;       // UNTESTED
+                       return 1;       // NOTEST - guard against reentry
                if (type->array.unspec && parse_time)
-                       return 1;       // UNTESTED
+                       return 1;       // NOTEST - unspec is still incomplete
                if (parse_time && type->array.vsize && !type->array.vsize->global)
-                       return 1;       // UNTESTED
+                       return 1;       // NOTEST - should be impossible
 
                if (type->array.vsize) {
                        vsize = var_value(c, type->array.vsize);
                        if (!vsize)
-                               return 1;       // UNTESTED
+                               return 1;       // NOTEST - should be impossible
                        mpz_init(q);
                        mpz_tdiv_q(q, mpq_numref(vsize->num), mpq_denref(vsize->num));
                        type->array.size = mpz_get_si(q);
@@ -2423,7 +2416,7 @@ with a const size by whether they are prepared at parse time or not.
                if (!parse_time)
                        return 1;
                if (type->array.member->size <= 0)
-                       return 0;       // UNTESTED
+                       return 0;       // NOTEST - error caught before here
 
                type->array.static_size = 1;
                type->size = type->array.size * type->array.member->size;
@@ -2467,26 +2460,23 @@ with a const size by whether they are prepared at parse time or not.
                        free(ptr);
        }
 
-       static int array_compat(struct type *require, struct type *have)
+       static int array_compat(struct type *require, struct type *have,
+                               enum val_rules rules)
        {
                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 (have->array.unspec && require->array.unspec) {
-                       if (have->array.vsize && require->array.vsize &&
-                           have->array.vsize != require->array.vsize)  // UNTESTED
-                               /* sizes might not be the same */
-                               return 0;       // UNTESTED
-                       return 1;
-               }
+               if (have->array.unspec && require->array.unspec &&
+                   have->array.size != require->array.size)
+                       return 0;       // NOTEST
                if (have->array.unspec || require->array.unspec)
-                       return 1;       // UNTESTED
+                       return 1;
                if (require->array.vsize == NULL && have->array.vsize == NULL)
                        return require->array.size == have->array.size;
 
-               return require->array.vsize == have->array.vsize;       // UNTESTED
+               return require->array.vsize == have->array.vsize;
        }
 
        static void array_print_type(struct type *type, FILE *f)
@@ -2560,29 +2550,18 @@ with a const size by whether they are prepared at parse time or not.
                $0->array.vsize = v;
        } }$
 
-###### Grammar
-       $*type
-       OptType -> Type ${ $0 = $<1; }$
-               | ${ $0 = NULL; }$
-
 ###### formal type grammar
 
-       | [ IDENTIFIER :: OptType ] Type ${ {
-               struct variable *v = var_decl(c, $ID.txt);
-
-               v->type = $<OT;
-               v->constant = 1;
-               if (!v->type)
-                       v->type = Tnum;
-               $0 = add_anon_type(c, &array_prototype, "array[var]");
-               $0->array.member = $<6;
+       | [ ] Type ${ {
+               $0 = add_anon_type(c, &array_prototype, "array[]");
+               $0->array.member = $<Type;
                $0->array.size = 0;
                $0->array.unspec = 1;
-               $0->array.vsize = v;
+               $0->array.vsize = NULL;
        } }$
 
 ###### Binode types
-       Index,
+       Index, Length,
 
 ###### term grammar
 
@@ -2594,6 +2573,13 @@ with a const size by whether they are prepared at parse time or not.
                $0 = b;
        } }$
 
+       | Term [ ] ${ {
+               struct binode *b = new(binode);
+               b->op = Length;
+               b->left = $<Term;
+               $0 = b;
+       } }$
+
 ###### print binode cases
        case Index:
                print_exec(b->left, -1, bracket);
@@ -2602,13 +2588,18 @@ with a const size by whether they are prepared at parse time or not.
                printf("]");
                break;
 
+       case Length:
+               print_exec(b->left, -1, bracket);
+               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, perr, Tnum, 0);
-               t = propagate_types(b->left, c, perr, NULL, rules & Rnoconstant);
+               propagate_types(b->right, c, perr_local, Tnum, 0);
+               t = propagate_types(b->left, c, perr, NULL, 0);
                if (!t || t->compat != array_compat) {
                        type_err(c, "error: %1 cannot be indexed", prog, t, 0, NULL);
                        return NULL;
@@ -2621,6 +2612,20 @@ with a const size by whether they are prepared at parse time or not.
                }
                break;
 
+       case Length:
+               /* left must be an array, result is a number
+                */
+               t = propagate_types(b->left, c, perr, NULL, 0);
+               if (!t || t->compat != array_compat) {
+                       type_err(c, "error: %1 cannot provide length", prog, t, 0, NULL);
+                       return NULL;
+               }
+               if (!type_compat(type, Tnum, rules))
+                       type_err(c, "error: have %1 but need %2", prog,
+                                        Tnum, rules, type);
+               return Tnum;
+               break;
+
 ###### interp binode cases
        case Index: {
                mpz_t q;
@@ -2646,6 +2651,13 @@ with a const size by whether they are prepared at parse time or not.
                ltype = NULL;
                break;
        }
+       case Length: {
+               lleft = linterp_exec(c, b->left, &ltype);
+               mpq_set_ui(rv.num, ltype->array.size, 1);
+               ltype = NULL;
+               rvtype = Tnum;
+               break;
+       }
 
 #### Structs
 
@@ -2923,24 +2935,31 @@ function will be needed.
        }
 
 ###### top level grammar
-       DeclareStruct -> struct IDENTIFIER FieldBlock Newlines ${ {
-               struct type *t;
-               t = find_type(c, $ID.txt);
-               if (!t)
-                       t = add_type(c, $ID.txt, &structure_prototype);
-               else if (t->size >= 0) {
+       $*type
+       StructName -> IDENTIFIER ${ {
+               struct type *t = find_type(c, $ID.txt);
+
+               if (t && t->size >= 0) {
                        tok_err(c, "error: type already declared", &$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 = NULL;
                }
-               t->structure.field_list = $<FB;
+               if (!t)
+                       t = add_type(c, $ID.txt, NULL);
                t->first_use = $ID;
+               $0 = t;
+       } }$
+       $void
+       DeclareStruct -> struct StructName FieldBlock Newlines ${ {
+               struct type *t = $<SN;
+               struct type tmp = *t;
+
+               *t = structure_prototype;
+               t->name = tmp.name;
+               t->next = tmp.next;
+               t->first_use = tmp.first_use;
+
+               t->structure.field_list = $<FB;
        } }$
 
        $*fieldlist
@@ -2950,10 +2969,17 @@ function will be needed.
        | SimpleFieldList EOL ${ $0 = $<SFL; }$
 
        FieldLines -> SimpleFieldList Newlines ${ $0 = $<SFL; }$
-       | FieldLines SimpleFieldList Newlines ${
-               $SFL->prev = $<FL;
-               $0 = $<SFL;
-       }$
+       | FieldLines SimpleFieldList Newlines ${ {
+               struct fieldlist *f = $<SFL;
+
+               if (f) {
+                       $0 = f;
+                       while (f->prev)
+                               f = f->prev;
+                       f->prev = $<FL;
+               } else
+                       $0 = $<FL;
+       } }$
 
        SimpleFieldList -> Field ${ $0 = $<F; }$
        | SimpleFieldList ; Field ${
@@ -2995,10 +3021,10 @@ function will be needed.
                        if (fl->type->print && fl->init) {
                                fprintf(f, " = ");
                                if (fl->type == Tstr)
-                                       fprintf(f, "\"");       // UNTESTED
+                                       fprintf(f, "\"");
                                print_value(fl->type, fl->init, f);
                                if (fl->type == Tstr)
-                                       fprintf(f, "\"");       // UNTESTED
+                                       fprintf(f, "\"");
                        }
                        fprintf(f, "\n");
                }
@@ -3124,8 +3150,12 @@ anything in the heap or on the stack.  A reference can be assigned
                /* Nothing to do here */
        }
 
-       static int reference_compat(struct type *require, struct type *have)
+       static int reference_compat(struct type *require, struct type *have,
+                                   enum val_rules rules)
        {
+               if (rules & Rrefok)
+                       if (require->reference.referent == have)
+                               return 1;
                if (have->compat != require->compat)
                        return 0;
                if (have->reference.referent != require->reference.referent)
@@ -3153,7 +3183,6 @@ anything in the heap or on the stack.  A reference can be assigned
                return Tnone;
        }
 
-
        static struct type reference_prototype = {
                .print_type = reference_print_type,
                .cmp_eq = reference_cmp,
@@ -3265,6 +3294,7 @@ anything in the heap or on the stack.  A reference can be assigned
                                r->reftype = type;
                                *perr |= Eretry;
                        }
+                       *perr |= Erval;
                        return type;
                case RefNil:
                        if (type && type->free != reference_free)
@@ -3274,9 +3304,10 @@ anything in the heap or on the stack.  A reference can be assigned
                                r->reftype = type;
                                *perr |= Eretry;
                        }
+                       *perr |= Erval;
                        return type;
                case RefFree:
-                       t = propagate_types(r->right, c, perr, NULL, 0);
+                       t = propagate_types(r->right, c, perr_local, NULL, 0);
                        if (t && t->free != reference_free)
                                type_err(c, "error: @free can only be assigned a reference, not %1",
                                         prog, t, 0, NULL);
@@ -3321,7 +3352,7 @@ anything in the heap or on the stack.  A reference can be assigned
 ###### Expressions: dereference
 
 ###### Binode types
-       Deref,
+       Deref, AddressOf,
 
 ###### term grammar
 
@@ -3337,25 +3368,46 @@ anything in the heap or on the stack.  A reference can be assigned
                print_exec(b->left, -1, bracket);
                printf("@");
                break;
+       case AddressOf:
+               print_exec(b->left, -1, bracket);
+               break;
 
 ###### propagate binode cases
        case Deref:
                /* left must be a reference, and we return what it refers to */
                /* FIXME how can I pass the expected type down? */
                t = propagate_types(b->left, c, perr, NULL, 0);
+               *perr &= ~Erval;
                if (!t || t->free != reference_free)
                        type_err(c, "error: Cannot dereference %1", b, t, 0, NULL);
                else
                        return t->reference.referent;
                break;
 
+       case AddressOf:
+               /* left must be lval, we create reference to it */
+               if (!type || type->free != reference_free)
+                       t = propagate_types(b->left, c, perr, type, 0); // NOTEST impossible
+               else
+                       t = propagate_types(b->left, c, perr,
+                                           type->reference.referent, 0);
+               if (t)
+                       t = find_anon_type(c, &reference_prototype, "@%.*s",
+                                       t->name.len, t->name.txt);
+               return t;
+
 ###### interp binode cases
-       case Deref: {
+       case Deref:
                left = interp_exec(c, b->left, &ltype);
                lrv = left.ref;
                rvtype = ltype->reference.referent;
                break;
-       }
+
+       case AddressOf:
+               rv.ref = linterp_exec(c, b->left, &rvtype);
+               rvtype = find_anon_type(c, &reference_prototype, "@%.*s",
+                                       rvtype->name.len, rvtype->name.txt);
+               break;
 
 
 #### Functions
@@ -3448,12 +3500,21 @@ further detailed when Expression Lists are introduced.
                val->function = NULL;
        }
 
-       static int function_compat(struct type *require, struct type *have)
+       static int function_compat(struct type *require, struct type *have,
+                                  enum val_rules rules)
        {
                // FIXME can I do anything here yet?
                return 0;
        }
 
+       static struct exec *take_addr(struct exec *e)
+       {
+               struct binode *rv = new(binode);
+               rv->op = AddressOf;
+               rv->left = e;
+               return rv;
+       }
+
        static void function_check_args(struct parse_context *c, enum prop_err *perr,
                                        struct type *require, struct exec *args)
        {
@@ -3465,13 +3526,22 @@ further detailed when Expression Lists are introduced.
 
                while (param) {
                        struct var *pv = cast(var, param->left);
+                       struct type *t = pv->var->type, *t2;
                        if (!arg) {
                                type_err(c, "error: insufficient arguments to function.",
                                         args, NULL, 0, NULL);
                                break;
                        }
                        *perr = 0;
-                       propagate_types(arg->left, c, perr, pv->var->type, 0);
+                       t2 = propagate_types(arg->left, c, perr, t, Rrefok);
+                       if (t->free == reference_free &&
+                           t->reference.referent == t2 &&
+                           !(*perr & Erval)) {
+                               arg->left = take_addr(arg->left);
+                       } else if (!(*perr & Efail) && !type_compat(t2, t, 0)) {
+                               type_err(c, "error: cannot pass rval when reference expected",
+                                        arg->left, NULL, 0, NULL);
+                       }
                        param = cast(binode, param->right);
                        arg = cast(binode, arg->right);
                }
@@ -3482,6 +3552,7 @@ further detailed when Expression Lists are introduced.
 
        static void function_print(struct type *type, struct value *val, FILE *f)
        {
+               fprintf(f, "\n");
                print_exec(val->function, 1, 0);
        }
 
@@ -3515,7 +3586,6 @@ further detailed when Expression Lists are introduced.
                        } else
                                type_print(type->function.return_type, f);
                }
-               fprintf(f, "\n");
        }
 
        static void function_free_type(struct type *t)
@@ -3673,10 +3743,11 @@ it in the "SimpleStatement Grammar" which will be described later.
                                 prog, NULL, 0, NULL);
                        return NULL;
                }
-               *perr |= Enoconst;
-               v->var->type->check_args(c, perr, v->var->type, args);
+               *perr |= Eruntime;
+               v->var->type->check_args(c, perr_local, v->var->type, args);
                if (v->var->type->function.inline_result)
                        *perr |= Emaycopy;
+               *perr |= Erval;
                return v->var->type->function.return_type;
        }
 
@@ -3789,9 +3860,9 @@ there.
                struct binode *b2 = cast(binode, b->right);
                struct type *t2;
 
-               propagate_types(b->left, c, perr, Tbool, 0);
-               t = propagate_types(b2->left, c, perr, type, Rnolabel);
-               t2 = propagate_types(b2->right, c, perr, type ?: t, Rnolabel);
+               propagate_types(b->left, c, perr_local, Tbool, 0);
+               t = propagate_types(b2->left, c, perr, type, 0);
+               t2 = propagate_types(b2->right, c, perr, type ?: t, 0);
                return t ?: t2;
        }
 
@@ -3801,7 +3872,7 @@ there.
                struct binode *b2 = cast(binode, b->right);
                left = interp_exec(c, b->left, &ltype);
                if (left.bool)
-                       rv = interp_exec(c, b2->left, &rvtype); // UNTESTED
+                       rv = interp_exec(c, b2->left, &rvtype);
                else
                        rv = interp_exec(c, b2->right, &rvtype);
                }
@@ -3861,15 +3932,12 @@ lists.  In that case a separate function is used to print them.
 ### Expressions: Boolean
 
 The next class of expressions to use the `binode` will be Boolean
-expressions.  "`and then`" and "`or else`" are similar to `and` and `or`
-have same corresponding precendence.  The difference is that they don't
+expressions.  `and` and `or` are short-circuit operators that don't
 evaluate the second expression if not necessary.
 
 ###### Binode types
        And,
-       AndThen,
        Or,
-       OrElse,
        Not,
 
 ###### declare terminals
@@ -3885,14 +3953,6 @@ evaluate the second expression if not necessary.
                b->right = $<3;
                $0 = b;
        } }$
-       | Expression or else Expression ${ {
-               struct binode *b = new(binode);
-               b->op = OrElse;
-               b->left = $<1;
-               b->right = $<4;
-               $0 = b;
-       } }$
-
        | Expression and Expression ${ {
                struct binode *b = new(binode);
                b->op = And;
@@ -3900,14 +3960,6 @@ evaluate the second expression if not necessary.
                b->right = $<3;
                $0 = b;
        } }$
-       | Expression and then Expression ${ {
-               struct binode *b = new(binode);
-               b->op = AndThen;
-               b->left = $<1;
-               b->right = $<4;
-               $0 = b;
-       } }$
-
        | not Expression ${ {
                struct binode *b = new(binode);
                b->op = Not;
@@ -3923,13 +3975,6 @@ evaluate the second expression if not necessary.
                print_exec(b->right, -1, bracket);
                if (bracket) printf(")");
                break;
-       case AndThen:
-               if (bracket) printf("(");
-               print_exec(b->left, -1, bracket);
-               printf(" and then ");
-               print_exec(b->right, -1, bracket);
-               if (bracket) printf(")");
-               break;
        case Or:
                if (bracket) printf("(");
                print_exec(b->left, -1, bracket);
@@ -3937,13 +3982,6 @@ evaluate the second expression if not necessary.
                print_exec(b->right, -1, bracket);
                if (bracket) printf(")");
                break;
-       case OrElse:
-               if (bracket) printf("(");
-               print_exec(b->left, -1, bracket);
-               printf(" or else ");
-               print_exec(b->right, -1, bracket);
-               if (bracket) printf(")");
-               break;
        case Not:
                if (bracket) printf("(");
                printf("not ");
@@ -3953,9 +3991,7 @@ evaluate the second expression if not necessary.
 
 ###### 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, perr, Tbool, 0);
@@ -3963,25 +3999,16 @@ evaluate the second expression if not necessary.
                if (type && type != Tbool)
                        type_err(c, "error: %1 operation found where %2 expected", prog,
                                   Tbool, 0, type);
+               *perr |= Erval;
                return Tbool;
 
 ###### interp binode cases
        case And:
-               rv = interp_exec(c, b->left, &rvtype);
-               right = interp_exec(c, b->right, &rtype);
-               rv.bool = rv.bool && right.bool;
-               break;
-       case AndThen:
                rv = interp_exec(c, b->left, &rvtype);
                if (rv.bool)
                        rv = interp_exec(c, b->right, NULL);
                break;
        case Or:
-               rv = interp_exec(c, b->left, &rvtype);
-               right = interp_exec(c, b->right, &rtype);
-               rv.bool = rv.bool || right.bool;
-               break;
-       case OrElse:
                rv = interp_exec(c, b->left, &rvtype);
                if (!rv.bool)
                        rv = interp_exec(c, b->right, NULL);
@@ -4073,17 +4100,18 @@ expression operator, and the `CMPop` non-terminal will match one of them.
        case Eql:
        case NEql:
                /* Both must match but not be labels, result is Tbool */
-               t = propagate_types(b->left, c, perr, NULL, Rnolabel);
+               t = propagate_types(b->left, c, perr, NULL, 0);
                if (t)
                        propagate_types(b->right, c, perr, t, 0);
                else {
-                       t = propagate_types(b->right, c, perr, NULL, Rnolabel); // UNTESTED
-                       if (t)  // UNTESTED
-                               t = propagate_types(b->left, c, perr, t, 0);    // UNTESTED
+                       t = propagate_types(b->right, c, perr, NULL, 0);        // NOTEST
+                       if (t)  // NOTEST
+                               t = propagate_types(b->left, c, perr, t, 0);    // NOTEST
                }
                if (!type_compat(type, Tbool, 0))
                        type_err(c, "error: Comparison returns %1 but %2 expected", prog,
                                    Tbool, rules, type);
+               *perr |= Erval;
                return Tbool;
 
 ###### interp binode cases
@@ -4240,9 +4268,10 @@ parentheses around an expression converts it into a Term,
                if (bracket) printf(")");
                break;
        case Bracket:
-               printf("(");
+               /* Avoid double brackets... */
+               if (!bracket) printf("(");
                print_exec(b->right, indent, bracket);
-               printf(")");
+               if (!bracket) printf(")");
                break;
 
 ###### propagate binode cases
@@ -4261,6 +4290,7 @@ parentheses around an expression converts it into a Term,
                if (!type_compat(type, Tnum, 0))
                        type_err(c, "error: Arithmetic returns %1 but %2 expected", prog,
                                   Tnum, rules, type);
+               *perr |= Erval;
                return Tnum;
 
        case Concat:
@@ -4270,15 +4300,17 @@ parentheses around an expression converts it into a Term,
                if (!type_compat(type, Tstr, 0))
                        type_err(c, "error: Concat returns %1 but %2 expected", prog,
                                   Tstr, rules, type);
+               *perr |= Erval;
                return Tstr;
 
        case StringConv:
                /* op must be string, result is number */
                propagate_types(b->left, c, perr, Tstr, 0);
                if (!type_compat(type, Tnum, 0))
-                       type_err(c,     // UNTESTED
+                       type_err(c,
                          "error: Can only convert string to number, not %1",
                                prog, type, 0, NULL);
+               *perr |= Erval;
                return Tnum;
 
        case Test:
@@ -4287,6 +4319,7 @@ parentheses around an expression converts it into a Term,
                if (!t || !t->test)
                        type_err(c, "error: '?' requires a testable value, not %1",
                                 prog, t, 0, NULL);
+               *perr |= Erval;
                return Tbool;
 
        case Choose:
@@ -4298,10 +4331,11 @@ parentheses around an expression converts it into a Term,
                if (t && t->test == NULL)
                        type_err(c, "error: \"??\" requires a testable value, not %1",
                                 prog, t, 0, NULL);
+               *perr |= Erval;
                return t;
 
        case Bracket:
-               return propagate_types(b->right, c, perr, type, 0);
+               return propagate_types(b->right, c, perr, type, rules);
 
 ###### interp binode cases
 
@@ -4363,19 +4397,19 @@ parentheses around an expression converts it into a Term,
                rvtype = Tnum;
 
                struct text tx = right.str;
-               char tail[3];
+               char tail[3] = "";
                int neg = 0;
                if (tx.txt[0] == '-') {
-                       neg = 1;        // UNTESTED
-                       tx.txt++;       // UNTESTED
-                       tx.len--;       // UNTESTED
+                       neg = 1;
+                       tx.txt++;
+                       tx.len--;
                }
                if (number_parse(rv.num, tail, tx) == 0)
-                       mpq_init(rv.num);       // UNTESTED
+                       mpq_init(rv.num);
                else if (neg)
-                       mpq_neg(rv.num, rv.num);        // UNTESTED
+                       mpq_neg(rv.num, rv.num);
                if (tail[0])
-                       printf("Unsupported suffix: %.*s\n", tx.len, tx.txt);   // UNTESTED
+                       printf("Unsupported suffix: %.*s\n", tx.len, tx.txt);
 
                break;
        case Test:
@@ -4475,7 +4509,8 @@ the common header for all reductions to use.
        Block -> { IN OptNL Statementlist OUT OptNL } ${ $0 = $<Sl; }$
        |        { SimpleStatements } ${ $0 = reorder_bilist($<SS); }$
        |        SimpleStatements ; ${ $0 = reorder_bilist($<SS); }$
-       |        SimpleStatements EOL ${ $0 = reorder_bilist($<SS); }$
+       |        SimpleStatements EOL ${ $0 = reorder_bilist($<SS); 
+               }$
        |        IN OptNL Statementlist OUT ${ $0 = $<Sl; }$
 
        OpenBlock -> OpenScope { IN OptNL Statementlist OUT OptNL } ${ $0 = $<Sl; }$
@@ -4484,7 +4519,7 @@ the common header for all reductions to use.
        |        OpenScope SimpleStatements EOL ${ $0 = reorder_bilist($<SS); }$
        |        IN OpenScope OptNL Statementlist OUT ${ $0 = $<Sl; }$
 
-       UseBlock -> { OpenScope IN OptNL Statementlist OUT OptNL } ${ $0 = $<Sl; }$
+       UseBlock -> { IN OpenScope OptNL Statementlist OUT OptNL } ${ $0 = $<Sl; }$
        |        { OpenScope SimpleStatements } ${ $0 = reorder_bilist($<SS); }$
        |        IN OpenScope OptNL Statementlist OUT ${ $0 = $<Sl; }$
 
@@ -4498,7 +4533,7 @@ the common header for all reductions to use.
 
        ComplexStatements -> ComplexStatements ComplexStatement ${
                if ($2 == NULL) {
-                       $0 = $<1;
+                       $0 = $<1;       // NOTEST - impossible
                } else {
                        $0 = new(binode);
                        $0->op = Block;
@@ -4508,7 +4543,7 @@ the common header for all reductions to use.
        }$
        | ComplexStatement ${
                if ($1 == NULL) {
-                       $0 = NULL;
+                       $0 = NULL;      // NOTEST - impossible
                } else {
                        $0 = new(binode);
                        $0->op = Block;
@@ -4548,25 +4583,13 @@ the common header for all reductions to use.
 
 ###### print binode cases
        case Block:
-               if (indent < 0) {
-                       // simple statement
-                       if (b->left == NULL)    // UNTESTED
-                               printf("pass"); // UNTESTED
-                       else
-                               print_exec(b->left, indent, bracket);   // UNTESTED
-                       if (b->right) { // UNTESTED
-                               printf("; ");   // UNTESTED
-                               print_exec(b->right, indent, bracket);  // UNTESTED
-                       }
-               } else {
-                       // block, one per line
-                       if (b->left == NULL)
-                               do_indent(indent, "pass\n");
-                       else
-                               print_exec(b->left, indent, bracket);
-                       if (b->right)
-                               print_exec(b->right, indent, bracket);
-               }
+               // block, one per line
+               if (b->left == NULL)
+                       do_indent(indent, "pass\n");
+               else
+                       print_exec(b->left, indent, bracket);
+               if (b->right)
+                       print_exec(b->right, indent, bracket);
                break;
 
 ###### propagate binode cases
@@ -4582,7 +4605,9 @@ the common header for all reductions to use.
                struct binode *e;
 
                for (e = b; e; e = cast(binode, e->right)) {
-                       t = propagate_types(e->left, c, perr, NULL, rules);
+                       *perr |= *perr_local;
+                       *perr_local = 0;
+                       t = propagate_types(e->left, c, perr_local, NULL, rules);
                        if ((rules & Rboolok) && (t == Tbool || t == Tnone))
                                t = NULL;
                        if (t == Tnone && e->right)
@@ -4594,7 +4619,7 @@ the common header for all reductions to use.
                                if (!type)
                                        type = t;
                                else if (t != type)
-                                       type_err(c, "error: expected %1%r, found %2",
+                                       type_err(c, "error: expected %1, found %2",
                                                 e->left, type, rules, t);
                        }
                }
@@ -4671,7 +4696,7 @@ printed.
                else
                        b = cast(binode, b->right);
                while (b) {
-                       propagate_types(b->left, c, perr, NULL, Rnolabel);
+                       propagate_types(b->left, c, perr_local, NULL, 0);
                        b = cast(binode, b->right);
                }
                break;
@@ -4783,29 +4808,53 @@ be declared at any time.
 
        case Assign:
        case Declare:
-               /* Both must match and not be labels,
+               /* Both must match, or left may be ref and right an lval
                 * Type must support 'dup',
                 * For Assign, left must not be constant.
                 * result is Tnone
                 */
-               t = propagate_types(b->left, c, perr, NULL,
-                                   Rnolabel | (b->op == Assign ? Rnoconstant : 0));
+               *perr &= ~(Erval | Econst);
+               t = propagate_types(b->left, c, perr, NULL, 0);
                if (!b->right)
                        return Tnone;
 
                if (t) {
-                       if (propagate_types(b->right, c, perr, t, 0) != t)
-                               if (b->left->type == Xvar)
-                                       type_err(c, "info: variable '%v' was set as %1 here.",
-                                                cast(var, b->left)->var->where_set, t, rules, NULL);
+                       struct type *t2 = propagate_types(b->right, c, perr_local,
+                                                         t, Rrefok);
+                       if (!t2 || t2 == t || (*perr_local & Efail))
+                               ; // No more effort needed
+                       else if (t->free == reference_free &&
+                                t->reference.referent == t2 &&
+                                !(*perr_local & Erval))
+                               b->right = take_addr(b->right);
+                       else if (t->free == reference_free &&
+                                t->reference.referent == t2 &&
+                                (*perr_local & Erval))
+                               type_err(c, "error: Cannot assign an rval to a reference.",
+                                        b, NULL, 0, NULL);
                } else {
-                       t = propagate_types(b->right, c, perr, NULL, Rnolabel);
+                       t = propagate_types(b->right, c, perr_local, NULL, 0);
                        if (t)
-                               propagate_types(b->left, c, perr, t,
-                                               (b->op == Assign ? Rnoconstant : 0));
+                               propagate_types(b->left, c, perr, t, 0);
                }
-               if (t && t->dup == NULL && !(*perr & Emaycopy))
+               if (*perr & Erval)
+                       type_err(c, "error: cannot assign to an rval", b,
+                                NULL, 0, NULL);
+               else if (b->op == Assign && (*perr & Econst)) {
+                       type_err(c, "error: Cannot assign to a constant: %v",
+                                b->left, NULL, 0, NULL);
+                       if (b->left->type == Xvar) {
+                               struct var *var = cast(var, b->left);
+                               struct variable *v = var->var;
+                               type_err(c, "info: name was defined as a constant here",
+                                        v->where_decl, NULL, 0, NULL);
+                       }
+               }
+               if (t && t->dup == NULL && !(*perr_local & Emaycopy))
                        type_err(c, "error: cannot assign value of type %1", b, t, 0, NULL);
+               if (b->left->type == Xvar && (*perr_local & Efail))
+                       type_err(c, "info: variable '%v' was set as %1 here.",
+                                cast(var, b->left)->var->where_set, t, rules, NULL);
                return Tnone;
 
                break;
@@ -4827,10 +4876,10 @@ be declared at any time.
                val = var_value(c, v);
                if (v->type->prepare_type)
                        v->type->prepare_type(c, v->type, 0);
-               if (b->right)
-                       dinterp_exec(c, b->right, val, v->type, 0);
-               else
+               if (!b->right)
                        val_init(v->type, val);
+               else
+                       dinterp_exec(c, b->right, val, v->type, 0);
                break;
        }
 
@@ -5254,9 +5303,7 @@ casepart` to track a list of case parts.
 
 ###### propagate binode cases
        case Loop:
-               t = propagate_types(b->right, c, perr, Tnone, 0);
-               if (!type_compat(Tnone, t, 0))
-                       *perr |= Efail; // UNTESTED
+               propagate_types(b->right, c, perr_local, Tnone, 0);
                return propagate_types(b->left, c, perr, type, rules);
 
 ###### propagate exec cases
@@ -5276,13 +5323,9 @@ casepart` to track a list of case parts.
                struct casepart *cp;
 
                t = propagate_types(cs->forpart, c, perr, Tnone, 0);
-               if (!type_compat(Tnone, t, 0))
-                       *perr |= Efail; // UNTESTED
 
                if (cs->looppart) {
                        t = propagate_types(cs->thenpart, c, perr, Tnone, 0);
-                       if (!type_compat(Tnone, t, 0))
-                               *perr |= Efail; // UNTESTED
                }
                if (cs->casepart == NULL) {
                        propagate_types(cs->condpart, c, perr, Tbool, 0);
@@ -5294,9 +5337,9 @@ casepart` to track a list of case parts.
                             cp && !t; cp = cp->next)
                                t = propagate_types(cp->value, c, perr, NULL, 0);
                        if (!t && cs->condpart)
-                               t = propagate_types(cs->condpart, c, perr, NULL, Rboolok);      // UNTESTED
+                               t = propagate_types(cs->condpart, c, perr, NULL, Rboolok);      // NOTEST
                        if (!t && cs->looppart)
-                               t = propagate_types(cs->looppart, c, perr, NULL, Rboolok);      // UNTESTED
+                               t = propagate_types(cs->looppart, c, perr, NULL, Rboolok);      // NOTEST
                        // Now we have a type (I hope) push it down
                        if (t) {
                                for (cp = cs->casepart; cp; cp = cp->next)
@@ -5312,8 +5355,8 @@ casepart` to track a list of case parts.
                        type = propagate_types(cs->elsepart, c, perr, NULL, rules);
                for (cp = cs->casepart;
                     cp && !type;
-                    cp = cp->next)     // UNTESTED
-                       type = propagate_types(cp->action, c, perr, NULL, rules);       // UNTESTED
+                    cp = cp->next)     // NOTEST
+                       type = propagate_types(cp->action, c, perr, NULL, rules);       // NOTEST
                if (type) {
                        if (!cs->looppart)
                                propagate_types(cs->thenpart, c, perr, type, rules);
@@ -5411,7 +5454,7 @@ various declarations in the parse context.
        | DeclarationList Declaration
 
        Declaration -> ERROR Newlines ${
-               tok_err(c,      // UNTESTED
+               tok_err(c,      // NOTEST
                        "error: unhandled parse error", &$1);
        }$
        | DeclareConstant
@@ -5532,7 +5575,7 @@ constants.
                                } while (perr & Eretry);
                                if (perr & Efail)
                                        c->parse_error += 1;
-                               else if (!(perr & Enoconst)) {
+                               else if (!(perr & Eruntime)) {
                                        progress = some;
                                        struct value res = interp_exec(
                                                c, vb->right, &v->var->type);
@@ -5640,8 +5683,8 @@ is a bit more interesting at this level.
                        struct value fn = {.function = code};
                        struct type *t;
                        var_block_close(c, CloseFunction, code);
-                       t = add_anon_type(c, &function_prototype, 
-                                         "func %.*s", name->name->name.len, 
+                       t = add_anon_type(c, &function_prototype,
+                                         "func %.*s", name->name->name.len,
                                          name->name->name.txt);
                        name->type = t;
                        t->function.params = reorder_bilist(args);
@@ -5717,10 +5760,13 @@ is a bit more interesting at this level.
                                struct value *val = var_value(&context, v);
                                printf("func %.*s", v->name->name.len, v->name->name.txt);
                                v->type->print_type_decl(v->type, stdout);
-                               if (brackets)
-                                       print_exec(val->function, 0, brackets);
-                               else
+                               if (brackets) {
+                                       printf(" {\n");
+                                       print_exec(val->function, 1, brackets);
+                                       printf("}\n");
+                               } else {
                                        print_value(v->type, val, stdout);
+                               }
                                printf("/* frame size %d */\n", v->type->function.local_size);
                                target -= 1;
                        }
@@ -5753,7 +5799,7 @@ is a bit more interesting at this level.
                                all_ok = 0;
                        if (!v->type->function.inline_result &&
                            !v->type->function.return_type->dup) {
-                               type_err(c, "error: function cannot return value of type %1", 
+                               type_err(c, "error: function cannot return value of type %1",
                                         v->where_decl, v->type->function.return_type, 0, NULL);
                        }
 
@@ -5822,15 +5868,12 @@ is a bit more interesting at this level.
                        struct value *vl = var_value(c, v->var);
                        struct value arg;
                        struct type *t;
-                       mpq_t argcq;
                        int i;
 
                        switch (anum++) {
                        case 0: /* argv */
                                t = v->var->type;
-                               mpq_init(argcq);
-                               mpq_set_ui(argcq, argc, 1);
-                               memcpy(var_value(c, t->array.vsize), &argcq, sizeof(argcq));
+                               t->array.size = argc;
                                t->prepare_type(c, t, 0);
                                array_init(v->var->type, vl);
                                for (i = 0; i < argc; i++) {
@@ -5884,7 +5927,7 @@ things which will likely grow as the languages grows.
                name:string
                alive:Boolean
 
-       func main(argv:[argc::]string)
+       func main(argv:[]string)
                print "Hello World, what lovely oceans you have!"
                print "Are there", five, "?"
                print pi, pie, "but", cake
@@ -5912,7 +5955,7 @@ things which will likely grow as the languages grows.
                a : number
                a = A;
                b:number = B
-               if a > 0 and then b > 0:
+               if a > 0 and b > 0:
                        while a != b:
                                if a < b:
                                        b = b - a