/*
* R : A Computer Language for Statistical Data Analysis
* Copyright (C) 1995, 1996 Robert Gentleman and Ross Ihaka
* Copyright (C) 1997--2008 The R Development Core Team
* Copyright (C) 2003, 2004 The R Foundation
* Copyright (C) 2010 bedatadriven
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.renjin.primitives.special;
import org.renjin.eval.Context;
import org.renjin.eval.EvalException;
import org.renjin.sexp.AtomicVector;
import org.renjin.sexp.Environment;
import org.renjin.sexp.FunctionCall;
import org.renjin.sexp.Null;
import org.renjin.sexp.PairList;
import org.renjin.sexp.SEXP;
import org.renjin.sexp.SpecialFunction;
import org.renjin.sexp.StringVector;
import org.renjin.sexp.Symbol;
import com.google.common.collect.Iterables;
public class SwitchFunction extends SpecialFunction {
public SwitchFunction() {
super("switch");
}
@Override
public SEXP apply(Context context, Environment rho, FunctionCall call, PairList args) {
return doApply(context, rho, call, args);
}
private static SEXP doApply(Context context, Environment rho, FunctionCall call, PairList args) {
EvalException.check(call.length() > 1, "argument \"EXPR\" is missing");
SEXP expr = context.evaluate(args.getElementAsSEXP(0),rho);
EvalException.check(expr.length() == 1, "EXPR must return a length 1 vector");
Iterable<PairList.Node> branches = Iterables.skip(args.nodes(), 1);
if(expr instanceof StringVector) {
String name = ((StringVector) expr).getElementAsString(0);
if(StringVector.isNA(name)) {
context.setInvisibleFlag();
return Null.INSTANCE;
}
SEXP partialMatch = null;
int partialMatchCount = 0;
for(PairList.Node node : branches) {
if(node.hasTag()) {
String branchName = node.getTag().getPrintName();
if(branchName.equals(name)) {
return context.evaluate( nextNonMissing(node), rho);
} else if(branchName.startsWith(name)) {
partialMatch = nextNonMissing(node);
partialMatchCount ++;
}
}
}
if(partialMatchCount == 1) {
return context.evaluate( partialMatch, rho);
} else if(Iterables.size(branches) > 0) {
PairList.Node last = Iterables.getLast(branches);
if(!last.hasTag()) {
return context.evaluate( last.getValue(), rho);
}
}
} else if(expr instanceof AtomicVector) {
int branchIndex = ((AtomicVector) expr).getElementAsInt(0);
if(branchIndex >= 1 && branchIndex <= Iterables.size(branches)) {
return context.evaluate( Iterables.get(branches, branchIndex-1).getValue(), rho);
}
}
// no match
return Null.INSTANCE;
}
private static SEXP nextNonMissing(PairList.Node node) {
do {
if(node.getValue() != Symbol.MISSING_ARG) {
return node.getValue();
}
if(!node.hasNextNode()) {
return Null.INSTANCE;
}
node = node.getNextNode();
} while(true);
}
public static SEXP matchAndApply(Context context, Environment rho, FunctionCall call, String[] argumentNames, SEXP[] arguments) {
PairList.Builder args = new PairList.Builder();
for(int i =0;i!=arguments.length;++i) {
args.add(argumentNames[i], arguments[i]);
}
return doApply(context, rho, call, args.build());
}
}