| // 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.devtools.build.lib.events.Location; |
| |
| /** Syntax node for an index expression. e.g. obj[field], but not obj[from:to] */ |
| public final class IndexExpression extends Expression { |
| |
| private final Expression obj; |
| |
| private final Expression key; |
| |
| public IndexExpression(Expression obj, Expression key) { |
| this.obj = obj; |
| this.key = key; |
| } |
| |
| public Expression getObject() { |
| return obj; |
| } |
| |
| public Expression getKey() { |
| return key; |
| } |
| |
| @Override |
| public String toString() { |
| return String.format("%s[%s]", obj, key); |
| } |
| |
| @Override |
| Object doEval(Environment env) throws EvalException, InterruptedException { |
| Object objValue = obj.eval(env); |
| Object keyValue = key.eval(env); |
| Location loc = getLocation(); |
| |
| if (objValue instanceof SkylarkIndexable) { |
| Object result = ((SkylarkIndexable) objValue).getIndex(keyValue, loc); |
| return SkylarkType.convertToSkylark(result, env); |
| } else if (objValue instanceof String) { |
| String string = (String) objValue; |
| int index = EvalUtils.getSequenceIndex(keyValue, string.length(), loc); |
| return string.substring(index, index + 1); |
| } |
| |
| throw new EvalException( |
| loc, |
| Printer.format( |
| "Type %s has no operator [](%s)", |
| EvalUtils.getDataTypeName(objValue), |
| EvalUtils.getDataTypeName(keyValue))); |
| } |
| |
| @Override |
| public void accept(SyntaxTreeVisitor visitor) { |
| visitor.visit(this); |
| } |
| |
| @Override |
| void validate(ValidationEnvironment env) throws EvalException { |
| obj.validate(env); |
| } |
| } |