[Ur] Error doing 'make smlnj' (trying to access UrWeb compiler interactively, within SML/NJ)

[Adam Chlipala]

On 12/24/2014 11:41 AM, Stefan Scott Alexander wrote:
> I was trying to learn more about the Grid1 demo, because it seems like 
> a very important example, but it's not always straightforward to 
> figure out what a lot of the code is doing - so I had been hoping that 
> even though UrWeb uses the MLton whole-program optimizing compiler and 
> there is no UrWeb REPL, I might be able to use SMLNJ to interactively 
> experiment with individual functions to get a better understanding of 
> what each one of them does. But I guess this won't be possible.

Sorry, no interactive execution of Ur/Web code.  Your strategy of 
writing web apps to test features is the right one, IMO.

Although, the type system here is so rich that you don't necessarily 
need to /run/ code!  You can stop at type checking by passing the '-tc' 
flag to 'urweb'.

> I thought I had a pretty good understanding of ML - but now I see that 
> all I have learned was the usual "toy" examples from reading 
> textbooks. When confronted with a real application such as the Grid1 
> demo (a non-trivial example using metaprogramming in UrWeb to 
> implement an Ajax-y CRUD interface for a 3-tier web app), I felt a bit 
> overwhelmed.

FWIW, probably most of the intricacy that you're running up against is 
found in neither ML nor Haskell.  It takes time to get used to the ways 
of dependent type theory!
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.impredicative.com/pipermail/ur/attachments/20141225/a464b252/attachment.html>