23 lines
539 B
Java
23 lines
539 B
Java
package function.builtin.predicate;
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import function.*;
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import sexpression.*;
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@FunctionNames({ "NULL" })
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public class NULL extends LispFunction {
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private ArgumentValidator argumentValidator;
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public NULL() {
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this.argumentValidator = new ArgumentValidator("NULL");
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this.argumentValidator.setExactNumberOfArguments(1);
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}
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public SExpression call(Cons argumentList) {
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argumentValidator.validate(argumentList);
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return argumentList.getFirst().isNull() ? Symbol.T : Nil.getInstance();
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}
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}
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