| // Copyright 2014 The Bazel Authors. All rights reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| package com.google.devtools.build.lib.syntax; |
| |
| import com.google.common.collect.ImmutableList; |
| import com.google.devtools.build.lib.syntax.SkylarkList.MutableList; |
| import com.google.devtools.build.lib.syntax.SkylarkList.Tuple; |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| /** |
| * Syntax node for list and tuple literals. |
| * |
| * <p>(Note that during evaluation, both list and tuple values are represented by java.util.List |
| * objects, the only difference between them being whether or not they are mutable.) |
| */ |
| public final class ListLiteral extends Expression { |
| |
| /** |
| * Types of the ListLiteral. |
| */ |
| // TODO(laurentlb): This conflicts with Expression.Kind, maybe remove it? |
| public enum Kind {LIST, TUPLE} |
| |
| private final Kind kind; |
| |
| private final List<Expression> elements; |
| |
| public ListLiteral(Kind kind, List<Expression> elements) { |
| this.kind = kind; |
| this.elements = elements; |
| } |
| |
| public static ListLiteral makeList(List<Expression> elements) { |
| return new ListLiteral(Kind.LIST, elements); |
| } |
| |
| public static ListLiteral makeTuple(List<Expression> elements) { |
| return new ListLiteral(Kind.TUPLE, elements); |
| } |
| |
| /** A new literal for an empty list, onto which a new location can be specified */ |
| public static ListLiteral emptyList() { |
| return makeList(ImmutableList.of()); |
| } |
| |
| public Kind getKind() { |
| return kind; |
| } |
| |
| public List<Expression> getElements() { |
| return elements; |
| } |
| |
| /** |
| * Returns true if this list is a tuple (a hash table, immutable list). |
| */ |
| public boolean isTuple() { |
| return kind == Kind.TUPLE; |
| } |
| |
| @Override |
| public void prettyPrint(Appendable buffer) throws IOException { |
| buffer.append(isTuple() ? '(' : '['); |
| String sep = ""; |
| for (Expression e : elements) { |
| buffer.append(sep); |
| e.prettyPrint(buffer); |
| sep = ", "; |
| } |
| if (isTuple() && elements.size() == 1) { |
| buffer.append(','); |
| } |
| buffer.append(isTuple() ? ')' : ']'); |
| } |
| |
| @Override |
| public String toString() { |
| return Printer.printAbbreviatedList( |
| elements, |
| isTuple(), |
| Printer.SUGGESTED_CRITICAL_LIST_ELEMENTS_COUNT, |
| Printer.SUGGESTED_CRITICAL_LIST_ELEMENTS_STRING_LENGTH); |
| } |
| |
| @Override |
| Object doEval(Environment env) throws EvalException, InterruptedException { |
| ArrayList<Object> result = new ArrayList<>(elements.size()); |
| for (Expression element : elements) { |
| // Convert NPEs to EvalExceptions. |
| if (element == null) { |
| throw new EvalException(getLocation(), "null expression in " + this); |
| } |
| result.add(element.eval(env)); |
| } |
| return isTuple() ? Tuple.copyOf(result) : MutableList.wrapUnsafe(env, result); |
| } |
| |
| @Override |
| public void accept(SyntaxTreeVisitor visitor) { |
| visitor.visit(this); |
| } |
| |
| @Override |
| public Expression.Kind kind() { |
| return Expression.Kind.LIST_LITERAL; |
| } |
| } |