59 lines
1.8 KiB
Java
59 lines
1.8 KiB
Java
package function.builtin;
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import static table.FunctionTable.lookupFunction;
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import java.text.MessageFormat;
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import error.LispException;
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import function.*;
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import sexpression.*;
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@FunctionNames({ "SYMBOL-FUNCTION" })
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public class SYMBOL_FUNCTION extends LispFunction {
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private ArgumentValidator argumentValidator;
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public SYMBOL_FUNCTION() {
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this.argumentValidator = new ArgumentValidator("SYMBOL-FUNCTION");
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this.argumentValidator.setExactNumberOfArguments(1);
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this.argumentValidator.setEveryArgumentExpectedType(Symbol.class);
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}
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public SExpression call(Cons argumentList) {
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argumentValidator.validate(argumentList);
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SExpression symbol = argumentList.getFirst();
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LispFunction function = lookupFunction(symbol.toString());
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if (function != null)
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return createRepresentation(symbol, function);
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throw new UndefinedSymbolFunctionException(symbol);
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}
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private SExpression createRepresentation(SExpression symbol, LispFunction function) {
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if (function instanceof UserDefinedFunction)
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return ((UserDefinedFunction) function).getLambdaExpression();
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String typeIndicator = function instanceof LispSpecialFunction ? "SPECIAL-FUNCTION" : "FUNCTION";
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return new Symbol(MessageFormat.format("#<{0} {1}>", typeIndicator, symbol));
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}
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public static class UndefinedSymbolFunctionException extends LispException {
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private static final long serialVersionUID = 1L;
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private SExpression function;
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public UndefinedSymbolFunctionException(SExpression function) {
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this.function = function;
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}
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@Override
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public String getMessage() {
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return MessageFormat.format("SYMBOL-FUNCTION: undefined function: {0}", function);
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}
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}
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}
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