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this software without specific prior written permission.
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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*/
package com.google.refine.grel.controls;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import org.json.JSONException;
import org.json.JSONWriter;
import com.google.refine.expr.EvalError;
import com.google.refine.expr.Evaluable;
import com.google.refine.expr.ExpressionUtils;
import com.google.refine.grel.Control;
import com.google.refine.grel.ControlFunctionRegistry;
import com.google.refine.grel.ast.VariableExpr;
public class ForRange implements Control {
@Override
public String checkArguments(Evaluable[] args) {
if (args.length != 5) {
return ControlFunctionRegistry.getControlName(this) + " expects 5 arguments";
} else if (!(args[3] instanceof VariableExpr)) {
return ControlFunctionRegistry.getControlName(this) +
" expects third argument to be the element's variable name";
}
return null;
}
@Override
public Object call(Properties bindings, Evaluable[] args) {
Object fromO = args[0].evaluate(bindings);
Object toO = args[1].evaluate(bindings);
Object stepO = args[2].evaluate(bindings);
if (ExpressionUtils.isError(fromO)) {
return fromO;
} else if (ExpressionUtils.isError(toO)) {
return toO;
} else if (ExpressionUtils.isError(stepO)) {
return stepO;
} else if (!(fromO instanceof Number) || !(toO instanceof Number) || !(stepO instanceof Number)) {
return new EvalError("First, second, and third arguments of forRange must all be numbers");
}
String indexName = ((VariableExpr) args[3]).getName();
Object oldIndexValue = bindings.get(indexName);
try {
List<Object> results = new ArrayList<Object>();
if (isIntegral((Number) fromO) && isIntegral((Number) stepO)) {
long from = ((Number) fromO).longValue();
long step = ((Number) stepO).longValue();
double to = ((Number) toO).doubleValue();
while (from < to) {
bindings.put(indexName, from);
Object r = args[4].evaluate(bindings);
results.add(r);
from += step;
}
} else {
double from = ((Number) fromO).longValue();
double step = ((Number) stepO).longValue();
double to = ((Number) toO).doubleValue();
while (from < to) {
bindings.put(indexName, from);
Object r = args[4].evaluate(bindings);
results.add(r);
from += step;
}
}
return results.toArray();
} finally {
/*
* Restore the old values bound to the variables, if any.
*/
if (oldIndexValue != null) {
bindings.put(indexName, oldIndexValue);
} else {
bindings.remove(indexName);
}
}
}
static private boolean isIntegral(Number o) {
if (o instanceof Integer || o instanceof Long) {
return true;
} else {
return (o.doubleValue() - o.longValue()) == 0;
}
}
@Override
public void write(JSONWriter writer, Properties options)
throws JSONException {
writer.object();
writer.key("description"); writer.value(
"Iterates over the variable v starting at \"from\", incrementing by \"step\" each time while less than \"to\". At each iteration, evaluates expression e, and pushes the result onto the result array."
);
writer.key("params"); writer.value("number from, number to, number step, variable v, expression e");
writer.key("returns"); writer.value("array");
writer.endObject();
}
}