47 lines
1.6 KiB
Java
47 lines
1.6 KiB
Java
package serene.simple;
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import java.util.function.Function;
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public class FnSpecialForm extends SpecialForm {
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public FnSpecialForm(ListNode paramsAndBody) {
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super(paramsAndBody);
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}
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@Override
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public Object eval(final Scope parentScope) {
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final ListNode<Node> formalParams = (ListNode<Node>) this.node.rest().first();
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final ListNode<Node> body = this.node.rest().rest();
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return new Function<Object, Object>() {
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@Override
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public Object apply(Object arg) {
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Object args[] = {arg};
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return this.apply(args);
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}
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public Object apply(Object... args) {
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Scope scope = new Scope(parentScope);
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if (args.length != formalParams.length) {
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throw new RuntimeException(String.format("Wrong number of arguments. Expected: %s, Got: %s.",
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formalParams.length,
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args.length));
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}
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// Map parameter values to formal parameter names
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int i = 0;
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for (Node param : formalParams) {
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SymbolNode paramSymbol = (SymbolNode) param;
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scope.insertSymbol(paramSymbol.name, args[i]);
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i++;
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}
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// Evaluate body
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Object output = null;
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for (Node node : body) {
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output = node.eval(scope);
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}
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return output;
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}
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};
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}
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}
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