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/*
 * #%L
 * Parsington: the SciJava mathematical expression parser.
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package org.scijava.parse.eval;

import java.util.HashMap;
import java.util.Map;

import org.scijava.parse.ExpressionParser;
import org.scijava.parse.SyntaxTree;
import org.scijava.parse.Tokens;
import org.scijava.parse.Variable;

/**
 * Base class for {@link Evaluator} implementations.
 *
 * @author Curtis Rueden
 */
public abstract class AbstractEvaluator implements Evaluator {

	private final HashMap vars = new HashMap();
	private final ExpressionParser parser;

	private boolean strict = true;

	public AbstractEvaluator() {
		this(new ExpressionParser());
	}

	public AbstractEvaluator(final ExpressionParser parser) {
		this.parser = parser;
	}

	// -- Evaluator methods --

	@Override
	public ExpressionParser getParser() {
		return parser;
	}

	@Override
	public boolean isStrict() {
		return strict;
	}

	@Override
	public void setStrict(final boolean strict) {
		this.strict = strict;
	}

	@Override
	public Object evaluate(final SyntaxTree syntaxTree) {
		// Convert the syntax tree to postfix.
		return evaluate(syntaxTree.postfix());
	}

	@Override
	public Object evaluate(final String expression) {
		// Convert the expression to postfix.
		return evaluate(parser.parsePostfix(expression));
	}

	@Override
	public Object value(final Object token) {
		return Tokens.isVariable(token) ? get((Variable) token) : token;
	}

	@Override
	public Object get(final Variable v) {
		final String name = v.getToken();
		if (vars.containsKey(name)) return vars.get(name);
		if (strict) throw new IllegalArgumentException("Unknown variable: " + name);
		return new Unresolved(name);
	}

	@Override
	public void set(final Variable v, final Object value) {
		vars.put(v.getToken(), value);
	}

	@Override
	public void setAll(final Map map) {
		vars.putAll(map);
	}

}