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799e2d1265
FunC's (and Tolk's before this PR) type system is based on Hindley-Milner.
This is a common approach for functional languages, where
types are inferred from usage through unification.
As a result, type declarations are not necessary:
() f(a,b) { return a+b; } // a and b now int, since `+` (int, int)
While this approach works for now, problems arise with the introduction
of new types like bool, where `!x` must handle both int and bool.
It will also become incompatible with int32 and other strict integers.
This will clash with structure methods, struggle with proper generics,
and become entirely impractical for union types.
This PR completely rewrites the type system targeting the future.
1) type of any expression is inferred and never changed
2) this is available because dependent expressions already inferred
3) forall completely removed, generic functions introduced
(they work like template functions actually, instantiated while inferring)
4) instantiation `<...>` syntax, example: `t.tupleAt<int>(0)`
5) `as` keyword, for example `t.tupleAt(0) as int`
6) methods binding is done along with type inferring, not before
("before", as worked previously, was always a wrong approach)
93 lines
2.8 KiB
C++
93 lines
2.8 KiB
C++
/*
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This file is part of TON Blockchain source code.
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TON Blockchain is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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TON Blockchain is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with TON Blockchain. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "tolk.h"
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#include "ast.h"
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#include "ast-visitor.h"
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#include "platform-utils.h"
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/*
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* This pipe checks for impure operations inside pure functions.
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* It happens after type inferring (after methods binding) since it operates fun_ref of calls.
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*/
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namespace tolk {
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GNU_ATTRIBUTE_NORETURN GNU_ATTRIBUTE_COLD
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static void fire_error_impure_operation_inside_pure_function(AnyV v) {
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v->error("an impure operation in a pure function");
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}
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class CheckImpureOperationsInPureFunctionVisitor final : public ASTVisitorFunctionBody {
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static void fire_if_global_var(AnyExprV v) {
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if (auto v_ident = v->try_as<ast_reference>()) {
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if (v_ident->sym->try_as<GlobalVarData>()) {
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fire_error_impure_operation_inside_pure_function(v);
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}
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}
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}
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void visit(V<ast_assign> v) override {
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fire_if_global_var(v->get_lhs());
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parent::visit(v);
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}
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void visit(V<ast_set_assign> v) override {
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fire_if_global_var(v->get_lhs());
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parent::visit(v);
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}
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void visit(V<ast_function_call> v) override {
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// v is `globalF(args)` / `globalF<int>(args)` / `obj.method(args)` / `local_var(args)` / `getF()(args)`
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if (!v->fun_maybe) {
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// `local_var(args)` is always impure, no considerations about what's there at runtime
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fire_error_impure_operation_inside_pure_function(v);
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}
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if (!v->fun_maybe->is_marked_as_pure()) {
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fire_error_impure_operation_inside_pure_function(v);
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}
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parent::visit(v);
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}
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void visit(V<ast_argument> v) override {
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if (v->passed_as_mutate) {
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fire_if_global_var(v->get_expr());
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}
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parent::visit(v);
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}
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void visit(V<ast_throw_statement> v) override {
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fire_error_impure_operation_inside_pure_function(v);
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}
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void visit(V<ast_assert_statement> v) override {
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fire_error_impure_operation_inside_pure_function(v);
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}
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public:
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bool should_visit_function(const FunctionData* fun_ref) override {
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return fun_ref->is_code_function() && !fun_ref->is_generic_function() && fun_ref->is_marked_as_pure();
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}
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};
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void pipeline_check_pure_impure_operations() {
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visit_ast_of_all_functions<CheckImpureOperationsInPureFunctionVisitor>();
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}
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} // namespace tolk
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