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
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
|
// 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.base.Preconditions;
import java.io.IOException;
import java.util.List;
import javax.annotation.Nullable;
/**
* Syntax node for a function argument.
*
* <p>Argument is a base class for arguments passed in a call (@see Argument.Passed)
* or defined as part of a function definition (@see Parameter).
* It is notably used by some {@link Parser} and printer functions.
*/
public abstract class Argument extends ASTNode {
public boolean isStar() {
return false;
}
public boolean isStarStar() {
return false;
}
/**
* Argument.Passed is the class of arguments passed in a function call
* (as opposed to being used in a definition -- @see Parameter for that).
* Argument.Passed is usually what we mean when informally say "argument".
*
* <p>An Argument.Passed can be Positional, Keyword, Star, or StarStar.
*/
public abstract static class Passed extends Argument {
/** the value to be passed by this argument */
protected final Expression value;
private Passed(Expression value) {
this.value = Preconditions.checkNotNull(value);
}
public boolean isPositional() {
return false;
}
public boolean isKeyword() {
return false;
}
@Nullable
public String getName() { // only for keyword arguments
return null;
}
public Expression getValue() {
return value;
}
@Override
public void accept(SyntaxTreeVisitor visitor) {
visitor.visit(this);
}
}
/** positional argument: Expression */
public static final class Positional extends Passed {
public Positional(Expression value) {
super(value);
}
@Override
public boolean isPositional() {
return true;
}
@Override
public void prettyPrint(Appendable buffer) throws IOException {
value.prettyPrint(buffer);
}
}
/** keyword argument: K = Expression */
public static final class Keyword extends Passed {
final String name;
public Keyword(String name, Expression value) {
super(value);
this.name = name;
}
@Override
public String getName() {
return name;
}
@Override
public boolean isKeyword() {
return true;
}
@Override
public void prettyPrint(Appendable buffer) throws IOException {
buffer.append(name);
buffer.append(" = ");
value.prettyPrint(buffer);
}
}
/** positional rest (starred) argument: *Expression */
public static final class Star extends Passed {
public Star(Expression value) {
super(value);
}
@Override
public boolean isStar() {
return true;
}
@Override
public void prettyPrint(Appendable buffer) throws IOException {
buffer.append('*');
value.prettyPrint(buffer);
}
}
/** keyword rest (star_starred) parameter: **Expression */
public static final class StarStar extends Passed {
public StarStar(Expression value) {
super(value);
}
@Override
public boolean isStarStar() {
return true;
}
@Override
public void prettyPrint(Appendable buffer) throws IOException {
buffer.append("**");
value.prettyPrint(buffer);
}
}
/** Some arguments failed to satisfy python call convention strictures */
protected static class ArgumentException extends Exception {
/** construct an ArgumentException from a message only */
public ArgumentException(String message) {
super(message);
}
}
/**
* Validate that the list of Argument's, whether gathered by the Parser or from annotations,
* satisfies the requirements of the Python calling conventions: all Positional's first,
* at most one Star, at most one StarStar, at the end only.
*/
public static void validateFuncallArguments(List<Passed> arguments)
throws ArgumentException {
boolean hasNamed = false;
boolean hasStar = false;
boolean hasKwArg = false;
for (Passed arg : arguments) {
if (hasKwArg) {
throw new ArgumentException("argument after **kwargs");
}
if (arg.isPositional()) {
if (hasNamed) {
throw new ArgumentException("non-keyword arg after keyword arg");
} else if (arg.isStar()) {
throw new ArgumentException("only named arguments may follow *expression");
}
} else if (arg.isKeyword()) {
hasNamed = true;
} else if (arg.isStar()) {
if (hasStar) {
throw new ArgumentException("more than one *stararg");
}
hasStar = true;
} else {
hasKwArg = true;
}
}
}
@Override
public final void prettyPrint(Appendable buffer, int indentLevel) throws IOException {
prettyPrint(buffer);
}
@Override
public abstract void prettyPrint(Appendable buffer) throws IOException;
}
|
