org.codehaus.groovy.transform.tailrec.VariableAccessReplacer.groovy Maven / Gradle / Ivy

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Groovy: A powerful, dynamic language for the JVM

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/*
 * Copyright 2013-2014 the original author or authors.
 *
 * 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 org.codehaus.groovy.transform.tailrec

import groovy.transform.CompileStatic
import org.codehaus.groovy.ast.ASTNode
import org.codehaus.groovy.ast.expr.VariableExpression

/**
 * Replace all access to variables and args by new variables.
 * The variable names to replace as well as their replacement name and type have to be configured
 * in nameAndTypeMapping before calling replaceIn().
 *
 * The VariableReplacedListener can be set if clients want to react to variable replacement.
 *
 * @author Johannes Link
 */
@CompileStatic
class VariableAccessReplacer {

    /**
     * Nested map of variable accesses to replace
     * e.g.: [
     *          'varToReplace': [name: 'newVar', type: TypeOfVar],
     *          'varToReplace2': [name: 'newVar2', type: TypeOfVar2],
     *       ]
     */
    Map nameAndTypeMapping = [:]

    VariableReplacedListener listener = VariableReplacedListener.NULL

    void replaceIn(ASTNode root) {
        Closure whenParam = { VariableExpression expr ->
            return nameAndTypeMapping.containsKey(expr.name)
        }
        Closure replaceWithLocalVariable = { VariableExpression expr ->
            Map nameAndType = nameAndTypeMapping[expr.name]
            VariableExpression newVar = AstHelper.createVariableReference(nameAndType)
            listener.variableReplaced(expr, newVar)
            return newVar
        }
        new VariableExpressionReplacer(when: whenParam, replaceWith: replaceWithLocalVariable).replaceIn(root)
    }

}

@CompileStatic
interface VariableReplacedListener {
    void variableReplaced(VariableExpression oldVar, VariableExpression newVar)

    static VariableReplacedListener NULL = new VariableReplacedListener() {
        @Override
        void variableReplaced(VariableExpression oldVar, VariableExpression newVar) {
            //do nothing
        }
    }
}