transcendental-lisp/src/function/builtin/special/SETQ.java

40 lines
1.1 KiB
Java

package function.builtin.special;
import static function.builtin.EVAL.eval;
import static function.builtin.SET.set;
import static function.builtin.cons.LIST.makeList;
import function.ArgumentValidator;
import function.FunctionNames;
import function.LispSpecialFunction;
import sexpression.Cons;
import sexpression.SExpression;
import sexpression.Symbol;
@FunctionNames({ "SETQ" })
public class SETQ extends LispSpecialFunction {
private ArgumentValidator argumentValidator;
public SETQ(String name) {
this.argumentValidator = new ArgumentValidator(name);
this.argumentValidator.setExactNumberOfArguments(2);
this.argumentValidator.setFirstArgumentExpectedType(Symbol.class);
}
@Override
public SExpression call(Cons argumentList) {
argumentValidator.validate(argumentList);
return set(evaluateValueOnly(argumentList));
}
private Cons evaluateValueOnly(Cons argumentList) {
Cons rest = (Cons) argumentList.getRest();
SExpression value = eval(rest.getFirst());
return new Cons(argumentList.getFirst(), makeList(value));
}
}