Thanks for the feedback.
Artyom Shalkhakov wrote:
Weird things are happening with the attached program.
- the Unicode text is displayed correctly when pages are statically
generated (that is, in the case of postMain) but when a remote call
for data is made, the text is turned to garbage.
- a form generated by asyncMain is displayed incorrectly in Firefox
3.0 (somehow, both<input>s are moved outside of<body> tag), but okay
in Chromium and Midori.
Would you mind opening a Mantis issue for each of these problems?
http://www.impredicative.com/mantis/
What happens when an RPC fails?
All handlers registered with [Basis.onConnectFail] are called. If you
haven't set any handlers, you get a generic alert box. The thread
waiting for the RPC result is aborted.
Is RPC synchronous or not?
It's synchronous, in the sense that a thread that makes an RPC suspends
until the result is available.
How is asynchronous message passing implemented?
It's the standard long-polling approach. Clients hit a special URL on
the server. When the next message is available, it is returned as the
HTTP result.
Also, how do you develop against Ur/Web? (e.g., when one uses a
mainstream scripting language, the development cycle goes like this:
"write or fix -> fire up a browser -> notice nothing works ->
repeat".)
I think you just add a "compile" step in the second slot, with a nested
loop between that step and the "write or fix" step, to deal with
compile-time errors. It would be possible to add a #! line at the start
of the Ur source and get it compiled on-the-fly as needed, but the
compiler is so slow that I wouldn't recommend it. (You'd also have to
write your own wrapper to implement this.)
Is REPL functionality planned?
I'm not planning that for any time soon. Since the only compiler is
whole-program, a REPL would require significant extra implementation.
And finally, is there a more accessible introduction for the rest of
us than the raw typing judgments in the manual? If not, what do you
recommend to read on type theory? (I'm interested in not only using
Ur/Web for shipping applications, but also in its inner workings.)
Benjamin Pierce's "Types and Programming Languages" should be an
adequate introduction, though it also covers many topics that are not
needed. I've tried to design Ur/Web so that it's fairly straightforward
to stick to the ML-like fragment, with the main possible source of
confusion being error messages that mention advanced features
explicitly. I'm also planning to, in the next few months, create a wiki
where different kinds of learning material can be maintained.
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