41 lines
936 B
Java
41 lines
936 B
Java
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/*
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* Name: Mike Cifelli
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* Course: CIS 443 - Programming Languages
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* Assignment: Lisp Interpreter 1
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*/
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package eval;
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import parser.*;
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/**
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* <code>LIST</code> represents the LIST function in Lisp.
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*/
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public class LIST extends LispFunction {
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/**
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* Places the given S-expression into a list.
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*
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* @param sexpr
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* the S-expression to be placed into a list
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* @return
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* a list with <code>sexpr</code> as the car and NIL as the cdr.
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*/
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public static Cons makeList(SExpression sexpr) {
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return new Cons(sexpr, Nil.getUniqueInstance());
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}
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public Cons call(Cons argList) {
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if (argList.nullp()) {
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// return NIL if there were no arguments passed to LIST
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return Nil.getUniqueInstance();
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}
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SExpression argCar = argList.getCar();
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Cons argCdr = (Cons) argList.getCdr();
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return new Cons(argCar, call(argCdr));
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}
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}
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