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mirror of https://github.com/ton-blockchain/ton synced 2025-03-09 15:40:10 +00:00

[Tolk] Nullable types T? and null safety

This commit introduces nullable types `T?` that are
distinct from non-nullable `T`.
Example: `int?` (int or null) and `int` are different now.
Previously, `null` could be assigned to any primitive type.
Now, it can be assigned only to `T?`.

A non-null assertion operator `!` was also introduced,
similar to `!` in TypeScript and `!!` in Kotlin.

If `int?` still occupies 1 stack slot, `(int,int)?` and
other nullable tensors occupy N+1 slots, the last for
"null precedence". `v == null` actually compares that slot.
Assigning `(int,int)` to `(int,int)?` implicitly creates
a null presence slot. Assigning `null` to `(int,int)?` widens
this null value to 3 slots. This is called "type transitioning".

All stdlib functions prototypes have been updated to reflect
whether they return/accept a nullable or a strict value.

This commit also contains refactoring from `const FunctionData*`
to `FunctionPtr` and similar.
This commit is contained in:
tolk-vm 2025-02-24 20:13:36 +03:00
parent 1389ff6789
commit f3e620f48c
No known key found for this signature in database
GPG key ID: 7905DD7FE0324B12
62 changed files with 2031 additions and 702 deletions

View file

@ -53,7 +53,7 @@ struct OptimizerBooleanExpressionsReplacer final : ASTReplacerInFunctionBody {
auto v_not = createV<ast_unary_operator>(loc, "!", tok_logical_not, rhs);
v_not->assign_inferred_type(TypeDataBool::create());
v_not->assign_rvalue_true();
v_not->assign_fun_ref(lookup_global_symbol("!b_")->as<FunctionData>());
v_not->assign_fun_ref(lookup_global_symbol("!b_")->try_as<FunctionPtr>());
return v_not;
}
@ -75,7 +75,7 @@ protected:
auto v_neq = createV<ast_binary_operator>(v->loc, "!=", tok_neq, cond_not_not, v_zero);
v_neq->mutate()->assign_rvalue_true();
v_neq->mutate()->assign_inferred_type(TypeDataBool::create());
v_neq->mutate()->assign_fun_ref(lookup_global_symbol("_!=_")->as<FunctionData>());
v_neq->mutate()->assign_fun_ref(lookup_global_symbol("_!=_")->try_as<FunctionPtr>());
return v_neq;
}
}
@ -117,12 +117,17 @@ protected:
}
v = createV<ast_if_statement>(v->loc, !v->is_ifnot, v_cond_unary->get_rhs(), v->get_if_body(), v->get_else_body());
}
// `if (x != null)` -> ifnot(x == null)
if (auto v_cond_isnull = v->get_cond()->try_as<ast_is_null_check>(); v_cond_isnull && v_cond_isnull->is_negated) {
v_cond_isnull->mutate()->assign_is_negated(!v_cond_isnull->is_negated);
v = createV<ast_if_statement>(v->loc, !v->is_ifnot, v_cond_isnull, v->get_if_body(), v->get_else_body());
}
return v;
}
public:
bool should_visit_function(const FunctionData* fun_ref) override {
bool should_visit_function(FunctionPtr fun_ref) override {
return fun_ref->is_code_function() && !fun_ref->is_generic_function();
}
};