public Value Visit(Expr.Sequence seq)
{
Value evaled = new Value.VUnit(seq.Span);
foreach (Expr e in seq.Exprs)
{
evaled = InterpreterVisitor.Interpret(_env, e);
}
return(evaled);
}
public Value Visit(Expr.Application app)
{
Value fn = InterpreterVisitor.Interpret(_env, app.Fn);
if (fn.Type() != TypeName.Lambda)
{
throw new ErrorBuilder().Msg($"expected a lambda, found a {fn.Type().Display()}").Type(ErrorType.Type)
.Span(app.Fn.Span).Build();
}
Value.VLambda lam = (Value.VLambda)fn;
return(lam.Lam(new Thunk(() =>
{
Value val = InterpreterVisitor.Interpret(_env, app.Arg);
val.Span = app.Span;
return val;
})));
}
public Value Visit(Expr.Assignment assign)
{
_env.Define(assign.Name.Name, new Thunk(() => InterpreterVisitor.Interpret(_env, assign.Value)),
assign.Span);
return(_env.Lookup(assign.Name));
}
public VLambda(Env env, Expr.Variable binder, Expr expr, Span span) : base(span)
{
Lam = (th) => InterpreterVisitor.Interpret(new Env(env, binder.Name, th), expr);
}
