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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)
64 lines
2.5 KiB
C++
64 lines
2.5 KiB
C++
/*
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This file is part of TON Blockchain Library.
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TON Blockchain Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 2 of the License, or
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(at your option) any later version.
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TON Blockchain Library 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 Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with TON Blockchain Library. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include "src-file.h"
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#include "fwd-declarations.h"
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#include "td/utils/Status.h"
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#include <vector>
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namespace tolk {
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// when a function is declared `f<T>`, this "<T>" is represented as this class
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// (not at AST, but at symbol storage level)
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struct GenericsDeclaration {
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struct GenericsItem {
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std::string_view nameT;
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explicit GenericsItem(std::string_view nameT)
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: nameT(nameT) {}
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};
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explicit GenericsDeclaration(std::vector<GenericsItem>&& itemsT)
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: itemsT(std::move(itemsT)) {}
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const std::vector<GenericsItem> itemsT;
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std::string as_human_readable() const;
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size_t size() const { return itemsT.size(); }
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bool has_nameT(std::string_view nameT) const { return find_nameT(nameT) != -1; }
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int find_nameT(std::string_view nameT) const;
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std::string get_nameT(int idx) const { return static_cast<std::string>(itemsT[idx].nameT); }
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};
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// when a function call is `f<int>()`, this "<int>" is represented as this class
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struct GenericsInstantiation {
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const std::vector<TypePtr> substitutions; // <SomeStruct, int> for genericTs <T1, T2>
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const SrcLocation loc; // first instantiation location
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explicit GenericsInstantiation(SrcLocation loc, std::vector<TypePtr>&& substitutions)
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: substitutions(std::move(substitutions))
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, loc(loc) {
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}
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};
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std::string generate_instantiated_name(const std::string& orig_name, const std::vector<TypePtr>& substitutions);
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td::Result<std::vector<TypePtr>> deduce_substitutionTs_on_generic_func_call(const FunctionData* called_fun, std::vector<TypePtr>&& arg_types, TypePtr return_hint);
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const FunctionData* instantiate_generic_function(SrcLocation loc, const FunctionData* fun_ref, const std::string& inst_name, std::vector<TypePtr>&& substitutionTs);
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} // namespace tolk
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