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// Copyright 2014 Google Inc. 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 javax.annotation.Nullable;
/**
* Syntax node for a Parameter in a function (or lambda) definition; it's a subclass of Argument,
* and contrasts with the class Argument.Passed of arguments in a function call.
*
* <p>There are four concrete subclasses of Parameter: Mandatory, Optional, Star, StarStar.
*
* <p>See FunctionSignature for how a valid list of Parameter's is organized as a signature, e.g.
* def foo(mandatory, optional = e1, *args, mandatorynamedonly, optionalnamedonly = e2, **kw): ...
*
* <p>V is the class of a defaultValue (Expression at compile-time, Object at runtime),
* T is the class of a type (Expression at compile-time, SkylarkType at runtime).
*/
public abstract class Parameter<V, T> extends Argument {
@Nullable protected String name;
@Nullable protected final T type;
private Parameter(@Nullable String name, @Nullable T type) {
this.name = name;
this.type = type;
}
private Parameter(@Nullable String name) {
this.name = name;
this.type = null;
}
public boolean isMandatory() {
return false;
}
public boolean isOptional() {
return false;
}
public boolean isStar() {
return false;
}
public boolean isStarStar() {
return false;
}
@Nullable public String getName() {
return name;
}
public boolean hasName() {
return true;
}
@Nullable public T getType() {
return type;
}
@Nullable public V getDefaultValue() {
return null;
}
/** mandatory parameter (positional or key-only depending on position): Ident */
public static class Mandatory<V, T> extends Parameter<V, T> {
public Mandatory(String name) {
super(name);
}
public Mandatory(String name, @Nullable T type) {
super(name, type);
}
@Override public boolean isMandatory() {
return true;
}
@Override
public String toString() {
return name.toString();
}
}
/** optional parameter (positional or key-only depending on position): Ident = Value */
public static class Optional<V, T> extends Parameter<V, T> {
public final V defaultValue;
public Optional(String name, @Nullable V defaultValue) {
super(name);
this.defaultValue = defaultValue;
}
public Optional(String name, @Nullable T type, @Nullable V defaultValue) {
super(name, type);
this.defaultValue = defaultValue;
}
@Override @Nullable public V getDefaultValue() {
return defaultValue;
}
@Override public boolean isOptional() {
return true;
}
@Override
public String toString() {
return name + "=" + defaultValue;
}
}
/** extra positionals parameter (star): *identifier */
public static class Star<V, T> extends Parameter<V, T> {
public Star(@Nullable String name, @Nullable T type) {
super(name, type);
}
public Star(@Nullable String name) {
super(name);
}
@Override
public boolean hasName() {
return name != null;
}
@Override public boolean isStar() {
return true;
}
@Override public String toString() {
if (name == null) {
return "*";
} else {
return "*" + name;
}
}
}
/** extra keywords parameter (star_star): **identifier */
public static class StarStar<V, T> extends Parameter<V, T> {
public StarStar(String name, @Nullable T type) {
super(name, type);
}
public StarStar(String name) {
super(name);
}
@Override public boolean isStarStar() {
return true;
}
@Override
public String toString() {
return "**" + name;
}
}
@Override
public void accept(SyntaxTreeVisitor visitor) {
visitor.visit(this);
}
}
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