plantuml/src/net/sourceforge/plantuml/tim/stdlib/VariableExists.java

/* ========================================================================
 * PlantUML : a free UML diagram generator
 * ========================================================================
 *
 * (C) Copyright 2009-2020, Arnaud Roques
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 * Project Info:  http://plantuml.com
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 * PlantUML distributed in the hope that it will be useful, but
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 * Original Author:  Arnaud Roques
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package net.sourceforge.plantuml.tim.stdlib;

import java.util.List;

import net.sourceforge.plantuml.LineLocation;
import net.sourceforge.plantuml.tim.EaterException;
import net.sourceforge.plantuml.tim.TContext;
import net.sourceforge.plantuml.tim.TFunctionSignature;
import net.sourceforge.plantuml.tim.TMemory;
import net.sourceforge.plantuml.tim.expression.TValue;

public class VariableExists extends SimpleReturnFunction {

	public TFunctionSignature getSignature() {
		return new TFunctionSignature("%variable_exists", 1);
	}

	public boolean canCover(int nbArg) {
		return nbArg == 1;
	}

	public TValue executeReturnFunction(TContext context, TMemory memory, LineLocation location, List<TValue> args) throws EaterException {
		final String name = args.get(0).toString();
		return TValue.fromBoolean(memory.getVariable(name) != null);
	}

}