CS计算机代考程序代写 Java package typelang;

package typelang;

import java.util.List;

import typelang.AST.Exp;

public interface Value {
public String tostring();
static class RefVal implements Value { //New in the reflang
private int _loc = -1;
public RefVal(int loc) { _loc = loc; }
public String tostring() {
return “loc:” + this._loc;
}
public int loc() { return _loc; }
}
static class FunVal implements Value { //New in the funclang
private Env _env;
private List _formals;
private Exp _body;
public FunVal(Env env, List formals, Exp body) {
_env = env;
_formals = formals;
_body = body;
}
public Env env() { return _env; }
public List formals() { return _formals; }
public Exp body() { return _body; }
public String tostring() {
String result = “(lambda ( “;
for(String formal : _formals)
result += formal + ” “;
result += “) “;
result += _body.accept(new Printer.Formatter(), _env);
return result + “)”;
}
}
static class NumVal implements Value {
private double _val;
public NumVal(double v) { _val = v; }
public double v() { return _val; }
public String tostring() {
int tmp = (int) _val;
if(tmp == _val) return “” + tmp;
return “” + _val;
}
}
static class BoolVal implements Value {
private boolean _val;
public BoolVal(boolean v) { _val = v; }
public boolean v() { return _val; }
public String tostring() { if(_val) return “#t”; return “#f”; }
}
static class StringVal implements Value {
private java.lang.String _val;
public StringVal(String v) { _val = v; }
public String v() { return _val; }
public java.lang.String tostring() { return “” + _val; }
}
static class PairVal implements Value {
protected Value _fst;
protected Value _snd;
public PairVal(Value fst, Value snd) { _fst = fst; _snd = snd; }
public Value fst() { return _fst; }
public Value snd() { return _snd; }
public java.lang.String tostring() {
if(isList()) return listToString();
return “(” + _fst.tostring() + ” ” + _snd.tostring() + “)”;
}
private boolean isList() {
if(_snd instanceof Value.Null) return true;
if(_snd instanceof Value.PairVal &&
((Value.PairVal) _snd).isList()) return true;
return false;
}
private java.lang.String listToString() {
String result = “(“;
result += _fst.tostring();
Value next = _snd;
while(!(next instanceof Value.Null)) {
result += ” ” + ((PairVal) next)._fst.tostring();
next = ((PairVal) next)._snd;
}
return result + “)”;
}
}
static class Null implements Value {
public Null() {}
public String tostring() { return “()”; }
}
static class UnitVal implements Value {
public static final UnitVal v = new UnitVal();
public String tostring() { return “”; }
}
static class DynamicError implements Value {
private String message = “Unknown dynamic error.”;
public DynamicError(String message) { this.message = message; }
public String tostring() { return “” + message; }
}
}