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// 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.Optional;
import com.google.common.collect.ImmutableList;
import com.google.devtools.build.lib.syntax.compiler.DebugInfo;
import com.google.devtools.build.lib.syntax.compiler.LoopLabels;
import com.google.devtools.build.lib.syntax.compiler.VariableScope;
import net.bytebuddy.implementation.bytecode.ByteCodeAppender;
import java.util.ArrayList;
import java.util.List;
/**
* Syntax node for a function definition.
*/
public class FunctionDefStatement extends Statement {
private final Identifier ident;
private final FunctionSignature.WithValues<Expression, Expression> signature;
private final ImmutableList<Statement> statements;
private final ImmutableList<Parameter<Expression, Expression>> parameters;
public FunctionDefStatement(Identifier ident,
Iterable<Parameter<Expression, Expression>> parameters,
FunctionSignature.WithValues<Expression, Expression> signature,
Iterable<Statement> statements) {
this.ident = ident;
this.signature = signature;
this.statements = ImmutableList.copyOf(statements);
this.parameters = ImmutableList.copyOf(parameters);
}
@Override
void doExec(Environment env) throws EvalException, InterruptedException {
List<Expression> defaultExpressions = signature.getDefaultValues();
ArrayList<Object> defaultValues = null;
ArrayList<SkylarkType> types = null;
if (defaultExpressions != null) {
defaultValues = new ArrayList<>(defaultExpressions.size());
for (Expression expr : defaultExpressions) {
defaultValues.add(expr.eval(env));
}
}
env.update(
ident.getName(),
new UserDefinedFunction(
ident,
FunctionSignature.WithValues.<Object, SkylarkType>create(
signature.getSignature(), defaultValues, types),
statements,
env.getGlobals()));
}
@Override
public String toString() {
return "def " + ident + "(" + signature + "):\n";
}
public Identifier getIdent() {
return ident;
}
public ImmutableList<Statement> getStatements() {
return statements;
}
public ImmutableList<Parameter<Expression, Expression>> getParameters() {
return parameters;
}
public FunctionSignature.WithValues<Expression, Expression> getSignature() {
return signature;
}
@Override
public void accept(SyntaxTreeVisitor visitor) {
visitor.visit(this);
}
@Override
void validate(final ValidationEnvironment env) throws EvalException {
ValidationEnvironment localEnv = new ValidationEnvironment(env);
FunctionSignature sig = signature.getSignature();
FunctionSignature.Shape shape = sig.getShape();
ImmutableList<String> names = sig.getNames();
List<Expression> defaultExpressions = signature.getDefaultValues();
int positionals = shape.getPositionals();
int mandatoryPositionals = shape.getMandatoryPositionals();
int namedOnly = shape.getNamedOnly();
int mandatoryNamedOnly = shape.getMandatoryNamedOnly();
boolean starArg = shape.hasStarArg();
boolean kwArg = shape.hasKwArg();
int named = positionals + namedOnly;
int args = named + (starArg ? 1 : 0) + (kwArg ? 1 : 0);
int startOptionals = mandatoryPositionals;
int endOptionals = named - mandatoryNamedOnly;
int j = 0; // index for the defaultExpressions
for (int i = 0; i < args; i++) {
String name = names.get(i);
if (startOptionals <= i && i < endOptionals) {
defaultExpressions.get(j++).validate(env);
}
localEnv.declare(name, getLocation());
}
for (Statement stmts : statements) {
stmts.validate(localEnv);
}
}
@Override
ByteCodeAppender compile(
VariableScope scope, Optional<LoopLabels> loopLabels, DebugInfo debugInfo) {
throw new UnsupportedOperationException(
"Skylark does not support nested function definitions"
+ " and the current entry point for the compiler is UserDefinedFunction.");
}
}
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