tiny.chant.parse.auto

1const std = @import("std");2const ast = @import("../ast/root.zig");3const expression = @import("expression.zig");4const state = @import("state/root.zig");56const diagnostic = state.diagnostic;7const memory = state.memory;8const Error = @import("error.zig").Error;9const Parser = state.Parser;1011pub fn resolve(parser: *Parser, declared: *const ast.Type, initializer: ?*ast.Expr) Error!*const ast.Type {12    if (!contains(declared)) return declared;13    const value = initializer orelse14        return diagnostic.fail(parser, error.ExpectedType, "auto declarations require an initializer");15    const inferred = (try expression.inferType(parser, value)) orelse16        return diagnostic.fail(parser, error.UnsupportedConstruct, "auto initializer type cannot be inferred");17    const resolved = (try replace(parser, declared, inferred)) orelse18        return diagnostic.fail(parser, error.UnsupportedConstruct, "auto declarator shape does not match initializer");19    return resolved;20}2122pub fn contains(c_type: *const ast.Type) bool {23    if (c_type.kind == .auto_type) return true;24    if (c_type.child) |child| return contains(child);25    return false;26}2728fn replace(parser: *Parser, declared: *const ast.Type, inferred: *const ast.Type) Error!?*const ast.Type {29    if (declared.kind == .auto_type) return inferred;30    if (!contains(declared)) return declared;31    if (declared.kind != inferred.kind) return null;32    const type_origin = parser.nodes.typeOrigin(declared) orelse unreachable;33    const node = try memory.createType(34        parser,35        declared.*,36        memory.derivedType(type_origin, false),37    );38    if (declared.child) |declared_child| {39        const inferred_child = inferred.child orelse return null;40        node.child = (try replace(parser, declared_child, inferred_child)) orelse return null;41    }42    node.is_unsigned = inferred.is_unsigned;43    node.array_len = inferred.array_len;44    node.vla_len = inferred.vla_len;45    node.params = inferred.params;46    node.variadic = inferred.variadic;47    return node;48}4950test "auto resolves simple and pointer declarations" {51    const lexer = @import("../lexer/root.zig");52    var arena_state = std.heap.ArenaAllocator.init(std.testing.allocator);53    defer arena_state.deinit();54    const arena = arena_state.allocator();5556    const source = "1 + 0";57    const token_survey = try lexer.survey(source, "auto.c");58    const capacity = try lexer.Capacity.derive(token_survey.limits);59    const bytes = try arena.alignedAlloc(60        u8,61        .fromByteUnits(lexer.Storage.storage_alignment),62        capacity.storage_bytes,63    );64    var storage = try lexer.Storage.init(bytes, token_survey.limits);65    storage.activate();66    defer _ = storage.deinit();67    const tokens = try storage.fill(token_survey, source, "auto.c");68    var parser = try @import("state/test.zig").initParser(arena, tokens);69    const expr = try expression.parseExpression(&parser);70    const scalar = try resolve(&parser, &ast.types.auto_type, expr);71    try std.testing.expectEqual(ast.types.Kind.int_type, scalar.kind);7273    const pointer = try memory.createType(74        &parser,75        .{ .kind = .pointer, .child = &ast.types.auto_type },76        memory.directType(0, null),77    );78    const inferred = try memory.createType(79        &parser,80        .{ .kind = .pointer, .child = &ast.types.double_type },81        memory.directType(1, null),82    );83    const resolved = (try replace(&parser, pointer, inferred)).?;84    try std.testing.expectEqual(ast.types.Kind.double_type, resolved.child.?.kind);85}

1pub const auto = @import("auto.zig");