[Ur] Ur/Web on Raspbian

Tue Feb 23 11:35:55 EST 2016

Truthfully, I think it would be much nicer to just have urweb itself
emit a standalone C file, including the entire runtime system with it
(literally, copying its source into the output .c file). Then
'building it' is as trivial as either copying and compiling, or
running arm-linux-gnueabihf-gcc on your host machine, and copying the
result of that.

This sounds like an unusual strategy, but was part of the design of
JHC, an optimizing Haskell compiler. I think it was quite nice in
practice: the single C file it spit out was perfectly portable ISO C99
and worked everywhere. Ur/Web doesn't even expose the size of native
machine integers to the programmer, and the runtime weighs in at a few
thousand lines, which is very manageable in terms of overhead and
basic portability concerns, I think.

(This is more complex with FFI libraries - but truthfully I'm not
happy with them, either. I think it would be very nice if the Ur/Web
compiler supported 'natively' compiling C files into a resulting
Ur/Web binary, simply by taking a 'foo.c' file as input, running
'gcc', and linking it into the final link step. Perhaps that C
filename could be put in the .urp file. Either way, this is a feature
I like in GHC -- `ghc -O2 foo.c bar.hs` works -- and it makes it much
easier to test libraries to foreign code, and I speculate 99% of
everything I want to bind to does not need autoconf or any build
system wrapper. This strategy can fit in fine with the whole-C-file
approach, I think.)

Adam, I'm not sure what your thoughts are about a strategy like this.
I was actually thinking of it the other day, since I too want to
deploy a small Ur/Web application on a cheap ARM machine (well, it
could *probably* handle it with 2GB of RAM), and being able to just
copy 'sqlite3.c' and 'urweb_output.c' and compiling that would be
quite nice. But there would have to be quite a lot of 'shuffling' to
support this I think, so it's a longer term goal, and I can understand
if you don't care to review something like that at this time.

On Tue, Feb 23, 2016 at 10:23 AM, Karen Sargsyan
<karsar at ibms.sinica.edu.tw> wrote:
> I came to the same conclusion, so I'm more after an easy setup for making
> RPi web applications via
> C code produced by Ur/Web compiler hosted on a different machine.
> I'll share my setup, as soon as I figure out procedure, make script and test
> on several applications.
>
> Karen
>
>
> On 2/24/16 12:02 AM, Adam Chlipala wrote:
>>
>> Yes, let me reaffirm a general point here, which might dissuade you from
>> this quest: while the Ur/Web compiler produces unusually compact
>> executables, the compiler itself requires unusually much time and memory to
>> execute.  It's a whole-program optimizing compiler.
>>
>> On 02/23/2016 10:37 AM, Adrian Thompson wrote:
>>>
>>> Hello,
>>>
>>> I compiled Ur on the Beaglebone Black a long time ago.  There was some
>>> ARM
>>> issues when compiling - I can't remember what they were.  But the major
>>> issue you will find is that compiling Ur requires more RAM than you would
>>> expect.  Add 2GB of swap (swap file) and then compile for a long time
>>> lol.
>>>
>>> Adrian
>>>
>>>
>>> -----Original Message-----
>>> From: Ur [mailto:ur-bounces at impredicative.com] On Behalf Of karsar
>>> Sent: February 23, 2016 2:11 AM
>>> To: Sergey Mironov
>>> Cc: The Ur programming language
>>> Subject: Re: [Ur] Ur/Web on Raspbian
>>>
>>> I wanted to run Ur/Web compiler. I still want to try make it work on RPi,
>>> but your idea to produce C code instead is probably what I need, as my
>>> goal
>>> is to get a working application. I'll share my results in this thread
>>> later.
>>>
>>> With best regards,
>>> Karen
>>>
>>>
>>> -----Original message-----
>>> From:Sergey Mironov <grrwlf at gmail.com>
>>> To:karsar <karsar at ibms.sinica.edu.tw>,The Ur programming language
>>> <ur at impredicative.com> Date:Tue, 23 Feb 2016 15:45:55
>>> Subject:Re: [Ur] Ur/Web on Raspbian
>>>
>>> Hi. Do you want to run Ur/Web the compiler on ARM or just Ur/Web
>>> application? If the latter is a case, then you may think about asking
>>> Ur/Web
>>> to produce C-code instead of binary and then compile it with ARM GCC. You
>>> will need database library to link with, but it is not a problem. AFAIK,
>>> Ur/Web produces C code in any case (check out -debug flag creating
>>> /tmp/webapp.c) and then compiles it with GCC.
>>>
>>> Regards,
>>> Sergey
>>>
>>> PS I remember someone started similar topic on this list
>>>
>>> 2016-02-23 10:01 GMT+03:00 karsar <karsar at ibms.sinica.edu.tw>:
>>>>
>>>> Hi,
>>>>
>>>> As Ur/Web is after not only secure, but fast web applications, I'm
>>>> interested in checking how well those will run on a system with low
>>>> resources. I have several RPis (Raspberry Pi) of different
>>>> generations, therefore running Ur/Web application on them (Raspiban OS)
>>>
>>> seems to be a way to go.  Ur/Web  requires MLlton (there is no MLton
>>> package
>>> in Raspbian, as I know) and MLton may ask more memory than RPi has.
>>>>
>>>> Looks like cross-compilation is the only option. Did anyone try to get
>>>> Ur/Web working on RPi or other ARM based machine with low resources? If
>>>
>>> yes, could you provide details on the  required steps?
>>>>
>>>> With best regards,
>>>> Karen Sargsyan
>>>>
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>>>
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>>
>>
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-- 
Regards,
Austin - PGP: 4096R/0x91384671