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An S-Expression inspiried library focused on iterators.

There is a newer version: 1.1.23

package com.github.basking2.sdsai.itrex.functions.function;

import com.github.basking2.sdsai.itrex.EvaluationContext;
import com.github.basking2.sdsai.itrex.Evaluator;
import com.github.basking2.sdsai.itrex.SExprRuntimeException;
import com.github.basking2.sdsai.itrex.functions.FunctionInterface;
import com.github.basking2.sdsai.itrex.iterators.EvaluatingIterator;

import java.util.Iterator;

/**
 * A handy utility function that defines a function or retrieves a definition of one.
 *
 * The first argument to this is always a function name.
 * The optional second argument is a function body that will be registered under the given name.
 * If no function body is given, the previously defined function is looked up or an exception is thrown.
 */
public class FnFunction implements FunctionInterface> {
    private final Evaluator evaluator;

    public FnFunction(final Evaluator evaluator) {
        this.evaluator = evaluator;
    }

    @Override
    public FunctionInterface apply(Iterator iterator, EvaluationContext evaluationContext) {
        final Object functionName = iterator.next();
        final FunctionInterface functionImpl;

        if (iterator.hasNext()) {
            final Object functionBody;
            if (iterator instanceof EvaluatingIterator) {
                @SuppressWarnings("unchecked")
                final EvaluatingIterator