35 lines
956 B
Java
35 lines
956 B
Java
package function.builtin;
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import function.LispFunction;
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import sexpression.*;
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/**
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* <code>PRINT</code> represents the PRINT function in Lisp.
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*/
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public class PRINT extends LispFunction {
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// The number of arguments that PRINT takes.
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private static final int NUM_ARGS = 1;
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public SExpression call(Cons argList) {
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// retrieve the number of arguments passed to PRINT
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int argListLength = LENGTH.getLength(argList);
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// make sure we have received the proper number of arguments
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if (argListLength != NUM_ARGS) {
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Cons originalSExpr = new Cons(new Symbol("PRINT"), argList);
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String errMsg = "too " + ((argListLength > NUM_ARGS) ? "many" : "few") + " arguments given to PRINT: "
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+ originalSExpr;
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throw new RuntimeException(errMsg);
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}
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SExpression arg = argList.getCar();
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System.out.println(arg);
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return arg;
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}
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}
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