public override object VisitQuote([NotNull] SchemeParser.QuoteContext context)
{
var expr = (ISExpression)Visit(context.datum());
return(AtomHelper.CreateCons(
AtomHelper.SymbolFromString("quote"),
AtomHelper.CreateCons(expr, AtomHelper.Nil)));
}
private object CreateList(SchemeParser.DatumContext[] elements)
{
if (elements.Length == 0)
{
return(AtomHelper.Nil);
}
return(AtomHelper.CreateCons((ISExpression)Visit(elements.First()), (ISExpression)CreateList(elements.Skip(1).ToArray())));
}
public override ISExpression Compile(ISchemeVM vm, string i)
{
var exprs = ParserHelpers.Parse(i);
if (exprs.Length == 1)
{
return(exprs[0]);
}
return(AtomHelper.CreateCons(CompilerConstants.Begin, exprs.Unflatten()));
}
public static ISExpression Cons(IEnumerable <ISExpression> args)
{
var a = args.ToArray();
return(AtomHelper.CreateCons(a[0], a[1]));
}
private ISExpression RewriteLet(ISchemeVM vm, ISExpression expr)
{
List <ISExpression> vars = new List <ISExpression>(), vals = new List <ISExpression>();
ISExpression defs;
var x = expr as Cons;
var c = x.ListCount();
if (c < 3)
{
ThrowErr("let", "invalid number of arguments", expr.String());
}
// (let name ((var val) ...) body)
if (x.Get(1).IsSymbol())
{
var sym = x.Get(1);
defs = x.Get(2);
while (defs != AtomHelper.Nil)
{
var n = defs.GetUnsafeCar().GetUnsafeCar();
var v = defs.GetUnsafeCar().GetUnsafeCdr().GetUnsafeCar();
if (!n.IsSymbol())
{
ThrowErr("let", "invalid argument 'bindings'", x.String());
}
vars.Add(n);
vals.Add(v);
defs = defs.GetUnsafeCdr();
}
// ((lambda ()
// (define name (lambda (vars) body))
// (name vals)))
var body = x.GetUnsafeCdr().GetUnsafeCdr().GetUnsafeCdr();
var innerLambda = AtomHelper.CreateCons(
CompilerConstants.Lambda,
AtomHelper.CreateCons(vars.Unflatten(),
Compile(vm, body))
);
var define = AtomHelper.CreateList(CompilerConstants.Define, sym, innerLambda);
var loopCall = AtomHelper.CreateCons(sym, Compile(vm, vals.Unflatten()));
var outerLambda = AtomHelper.CreateList(CompilerConstants.Lambda, AtomHelper.Nil, define, loopCall);
return(AtomHelper.CreateList(outerLambda));
}
// (let ((var val) ...) body)
else if (x.Get(1).IsList())
{
defs = x.Get(1);
while (defs != AtomHelper.Nil)
{
var d = defs.GetUnsafeCar();
if (!d.IsList() || d.ListCount() != 2)
{
ThrowErr("let", "invalid argument 'bindings'", x.String());
}
var n = d.GetUnsafeCar();
var v = d.GetUnsafeCdr().GetUnsafeCar();
if (!n.IsSymbol())
{
ThrowErr("let", "invalid argument 'bindings'", x.String());
}
vars.Add(n);
vals.Add(v);
defs = defs.GetUnsafeCdr();
}
// ((lambda (vars) body) vals)
var body = x.GetUnsafeCdr().GetUnsafeCdr();
var lambda = AtomHelper.CreateCons(CompilerConstants.Lambda,
AtomHelper.CreateCons(vars.Unflatten(), Compile(vm, body)));
return(AtomHelper.CreateCons(lambda, Compile(vm, vals.Unflatten())));
}
ThrowErr("let", "invalid argument 'bindings'", x.String());
return(null);
}
private object CreatePair(SchemeParser.DatumContext[] elements)
{
return(AtomHelper.CreateCons((ISExpression)Visit(elements[0]), (ISExpression)Visit(elements[1])));
}