1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
|
// 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;
import java.io.IOException;
/** 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 void prettyPrint(Appendable buffer) throws IOException {
obj.prettyPrint(buffer);
buffer.append('[');
key.prettyPrint(buffer);
buffer.append(']');
}
@Override
Object doEval(Environment env) throws EvalException, InterruptedException {
Object objValue = obj.eval(env);
return eval(env, objValue);
}
/**
* This method can be used instead of eval(Environment) if we want to avoid `obj` being evaluated
* several times.
*/
Object eval(Environment env, Object objValue) throws EvalException, InterruptedException {
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);
}
}
|
