From: NeilBrown Date: Wed, 15 Dec 2021 10:02:48 +0000 (+1100) Subject: oceani: add tracking of rval vs lval X-Git-Url: https://ocean-lang.org/code/?p=ocean;a=commitdiff_plain;h=d445e961d9ca6d339f882607eb3685c78ed86f4a oceani: add tracking of rval vs lval We need to know when a value is an rval or an lval. So add an 'Erval' flag. If not an rval, it must be an lval. Also fix tracking of whether the lval is for a constant. Signed-off-by: NeilBrown --- diff --git a/csrc/oceani-tests.mdc b/csrc/oceani-tests.mdc index fc26950..50a26df 100644 --- a/csrc/oceani-tests.mdc +++ b/csrc/oceani-tests.mdc @@ -875,17 +875,17 @@ various places that `type_err()` are called. if 3 * 4 and not True: print "Weird" d:number = .fred + (d + b) = 12 ###### output: type_err1 .tmp.code:3:25: error: expected string found number .tmp.code:3:28: error: expected string found number .tmp.code:6:8: error: Cannot assign to a constant: b .tmp.code:5:8: info: name was defined as a constant here - .tmp.code:6:8: error: Cannot assign to a constant: b - .tmp.code:5:8: info: name was defined as a constant here .tmp.code:8:11: error: Arithmetic returns number but Boolean expected .tmp.code:9:20: error: expected number found label .tmp.code:9:8: info: variable 'd' was set as number here. + .tmp.code:10:8: error: cannot assign to an rval oceani: type error in program - not running. ###### test: type_err2 diff --git a/csrc/oceani.mdc b/csrc/oceani.mdc index dca2055..0f2174d 100644 --- a/csrc/oceani.mdc +++ b/csrc/oceani.mdc @@ -592,13 +592,15 @@ passed by reference. It has `Efail` set when an error is found, and 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 {Rboolok = 1<<1, Rnoconstant = 1<<2}; + enum val_rules {Rboolok = 1<<0,}; enum prop_err {Efail = 1<<0, Eretry = 1<<1, Eruntime = 1<<2, - Emaycopy = 1<<3}; + 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, @@ -606,6 +608,7 @@ If it remains unchanged at `0`, then no more propagation is needed. ###### core functions static struct type *__propagate_types(struct exec *prog, struct parse_context *c, enum prop_err *perr, + enum prop_err *perr_local, struct type *type, int rules) { struct type *t; @@ -631,8 +634,10 @@ If it remains unchanged at `0`, then no more propagation is needed. struct type *type, int 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; @@ -1313,6 +1318,7 @@ executable. if (!type_compat(type, val->vtype, rules)) type_err(c, "error: expected %1 found %2", prog, type, rules, val->vtype); + *perr |= Erval; return val->vtype; } @@ -1435,6 +1441,7 @@ match "case". if (!type_compat(type, Tlabel, rules)) type_err(c, "error: expected %1 found %2", prog, type, rules, Tlabel); + *perr |= Erval; return Tlabel; } ###### interp exec cases @@ -2266,13 +2273,6 @@ 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); @@ -2290,6 +2290,8 @@ correctly. } if (!v->global || v->frame_pos < 0) *perr |= Eruntime; + if (v->constant) + *perr |= Econst; if (!type) return v->type; return type; @@ -2599,8 +2601,8 @@ with a const size by whether they are prepared at parse time or not. /* 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; @@ -3257,6 +3259,7 @@ 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) @@ -3266,9 +3269,10 @@ 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); @@ -3335,6 +3339,7 @@ anything in the heap or on the stack. A reference can be assigned /* 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 @@ -3666,9 +3671,10 @@ it in the "SimpleStatement Grammar" which will be described later. return NULL; } *perr |= Eruntime; - v->var->type->check_args(c, perr, v->var->type, args); + 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; } @@ -3781,7 +3787,7 @@ there. struct binode *b2 = cast(binode, b->right); struct type *t2; - propagate_types(b->left, c, perr, Tbool, 0); + 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; @@ -3955,6 +3961,7 @@ 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 @@ -4076,6 +4083,7 @@ expression operator, and the `CMPop` non-terminal will match one of them. 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 @@ -4253,6 +4261,7 @@ 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: @@ -4262,6 +4271,7 @@ 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: @@ -4271,6 +4281,7 @@ parentheses around an expression converts it into a Term, type_err(c, // UNTESTED "error: Can only convert string to number, not %1", prog, type, 0, NULL); + *perr |= Erval; return Tnum; case Test: @@ -4279,6 +4290,7 @@ 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: @@ -4290,10 +4302,11 @@ 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 @@ -4663,7 +4676,7 @@ printed. else b = cast(binode, b->right); while (b) { - propagate_types(b->left, c, perr, NULL, 0); + propagate_types(b->left, c, perr_local, NULL, 0); b = cast(binode, b->right); } break; @@ -4780,23 +4793,35 @@ be declared at any time. * For Assign, left must not be constant. * result is Tnone */ - t = propagate_types(b->left, c, perr, NULL, - (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 (propagate_types(b->right, c, perr_local, 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); } else { - t = propagate_types(b->right, c, perr, NULL, 0); + 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 (*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 & Emaycopy)) + if (t && t->dup == NULL && !(*perr_local & Emaycopy)) type_err(c, "error: cannot assign value of type %1", b, t, 0, NULL); return Tnone; @@ -5246,7 +5271,7 @@ casepart` to track a list of case parts. ###### propagate binode cases case Loop: - t = propagate_types(b->right, c, perr, Tnone, 0); + t = propagate_types(b->right, c, perr_local, Tnone, 0); if (!type_compat(Tnone, t, 0)) *perr |= Efail; // UNTESTED return propagate_types(b->left, c, perr, type, rules);