typescript-to-lua
Version:
A generic TypeScript to Lua transpiler. Write your code in TypeScript and publish Lua!
93 lines • 4.9 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.transformSpreadElement = void 0;
exports.isOptimizedVarArgSpread = isOptimizedVarArgSpread;
const ts = require("typescript");
const CompilerOptions_1 = require("../../CompilerOptions");
const lua = require("../../LuaAST");
const utils_1 = require("../../utils");
const language_extensions_1 = require("../utils/language-extensions");
const lua_ast_1 = require("../utils/lua-ast");
const lualib_1 = require("../utils/lualib");
const scope_1 = require("../utils/scope");
const typescript_1 = require("../utils/typescript");
const multi_1 = require("./language-extensions/multi");
const vararg_1 = require("./language-extensions/vararg");
function isOptimizedVarArgSpread(context, symbol, identifier) {
var _a;
if (!ts.isSpreadElement((0, typescript_1.findFirstNonOuterParent)(identifier))) {
return false;
}
// Walk up, stopping at any scope types which could stop optimization
const scope = (0, scope_1.findScope)(context, scope_1.ScopeType.Function | scope_1.ScopeType.Try | scope_1.ScopeType.Catch | scope_1.ScopeType.File);
if (!scope) {
return;
}
// $vararg global constant
if ((0, vararg_1.isGlobalVarargConstant)(context, symbol, scope)) {
return true;
}
// Scope must be a function scope associated with a real ts function
if (!ts.isFunctionLike(scope.node)) {
return false;
}
// Scope cannot be an async function
if (ts.canHaveModifiers(scope.node) &&
((_a = ts.getModifiers(scope.node)) === null || _a === void 0 ? void 0 : _a.some(m => m.kind === ts.SyntaxKind.AsyncKeyword))) {
return false;
}
// Identifier must be a vararg in the local function scope's parameters
const isSpreadParameter = (p) => p.dotDotDotToken && ts.isIdentifier(p.name) && context.checker.getSymbolAtLocation(p.name) === symbol;
if (!scope.node.parameters.some(isSpreadParameter)) {
return false;
}
// De-optimize if already referenced outside of a spread, as the array may have been modified
if ((0, scope_1.hasReferencedSymbol)(context, scope, symbol)) {
return false;
}
// De-optimize if a function is being hoisted from below to above, as it may have modified the array
if ((0, scope_1.hasReferencedUndefinedLocalFunction)(context, scope)) {
return false;
}
return true;
}
// TODO: Currently it's also used as an array member
const transformSpreadElement = (node, context) => {
const tsInnerExpression = ts.skipOuterExpressions(node.expression);
if (ts.isIdentifier(tsInnerExpression)) {
const symbol = context.checker.getSymbolAtLocation(tsInnerExpression);
if (symbol && isOptimizedVarArgSpread(context, symbol, tsInnerExpression)) {
return context.luaTarget === CompilerOptions_1.LuaTarget.Lua50
? (0, lua_ast_1.createUnpackCall)(context, lua.createArgLiteral(), node)
: lua.createDotsLiteral(node);
}
}
const innerExpression = context.transformExpression(node.expression);
if ((0, multi_1.isMultiReturnCall)(context, tsInnerExpression))
return innerExpression;
const iterableExtensionType = (0, language_extensions_1.getIterableExtensionKindForNode)(context, node.expression);
if (iterableExtensionType) {
if (iterableExtensionType === language_extensions_1.IterableExtensionKind.Iterable) {
return (0, lualib_1.transformLuaLibFunction)(context, lualib_1.LuaLibFeature.LuaIteratorSpread, node, innerExpression);
}
else if (iterableExtensionType === language_extensions_1.IterableExtensionKind.Pairs) {
const objectEntries = (0, lualib_1.transformLuaLibFunction)(context, lualib_1.LuaLibFeature.ObjectEntries, node, innerExpression);
return (0, lua_ast_1.createUnpackCall)(context, objectEntries, node);
}
else if (iterableExtensionType === language_extensions_1.IterableExtensionKind.PairsKey) {
const objectKeys = (0, lualib_1.transformLuaLibFunction)(context, lualib_1.LuaLibFeature.ObjectKeys, node, innerExpression);
return (0, lua_ast_1.createUnpackCall)(context, objectKeys, node);
}
else {
(0, utils_1.assertNever)(iterableExtensionType);
}
}
const type = context.checker.getTypeAtLocation(node.expression); // not ts-inner expression, in case of casts
if ((0, typescript_1.isAlwaysArrayType)(context, type)) {
// All union members must be arrays to be able to shortcut to unpack call
return (0, lua_ast_1.createUnpackCall)(context, innerExpression, node);
}
return (0, lualib_1.transformLuaLibFunction)(context, lualib_1.LuaLibFeature.Spread, node, innerExpression);
};
exports.transformSpreadElement = transformSpreadElement;
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