Command Line Interface using FFI

Hi Guillermo,

On 29 Jan 2012, at 21:11, Guillermo Polito wrote:

> I've spent a few hours playing with Alien+FFI and I did want to have a Command line interface to play and use as a quick browser.
>
> Gofer it
>     squeaksource: 'CLInterface';
>     package: 'ConfigurationOfCLInterface';
>     load.
>
> ConfigurationOfCLInterface load.
>
>
> To play with it write a script, for example startCLI.st, with the following:
>
> CLInterface start
>
>
>
> And then, from the command line
>
> CogVM -vm-display-null <image> startCLI.st
>
>
> What it does support?
> - executes smalltalk expressions
> - handles the errors and shows them into the stdout (so it does not explode :P)
> - stores variables as a workspace
> Since I used standard C functions (fgets and printf only) this should work on every platform from scratch (having a VM with FFI working, of course)...
>
> The problems I've ran so far:
> - blocking FFI blocks the vm.  I've not tried yet to use threads through FFI (and I don't know if it works.  Does it?).  But It should be great to start a headless seaside server with a command line :/.
>
> Ok, it's a very simple thing, but it allows to execute a expression from a remote server via ssh without doing much :).
>
> Guille

Cool, but why do you need to access those C functions ?
You do know that you can access std* from Smalltalk, do you ?

Have a look at the FileStream class 'stdio' category.

Apart from that, nice small, readable and useful hack.

Regards,

Sven

On Sun, Jan 29, 2012 at 6:58 PM, Sven Van Caekenberghe <[hidden email]> wrote:

Hi Guillermo,

On 29 Jan 2012, at 21:11, Guillermo Polito wrote:

> I've spent a few hours playing with Alien+FFI and I did want to have a Command line interface to play and use as a quick browser.
>
> Gofer it
>     squeaksource: 'CLInterface';
>     package: 'ConfigurationOfCLInterface';
>     load.
>
> ConfigurationOfCLInterface load.
>
>
> To play with it write a script, for example startCLI.st, with the following:
>
> CLInterface start
>
>
>
> And then, from the command line
>
> CogVM -vm-display-null <image> startCLI.st
>
>
> What it does support?
> - executes smalltalk expressions
> - handles the errors and shows them into the stdout (so it does not explode :P)
> - stores variables as a workspace
> Since I used standard C functions (fgets and printf only) this should work on every platform from scratch (having a VM with FFI working, of course)...
>
> The problems I've ran so far:
> - blocking FFI blocks the vm.  I've not tried yet to use threads through FFI (and I don't know if it works.  Does it?).  But It should be great to start a headless seaside server with a command line :/.
>
> Ok, it's a very simple thing, but it allows to execute a expression from a remote server via ssh without doing much :).
>
> Guille

Cool, but why do you need to access those C functions ?
You do know that you can access std* from Smalltalk, do you ?

No! :D
 

Have a look at the FileStream class 'stdio' category.

will do :).  Will that solve the vm-block issue?
 

Apart from that, nice small, readable and useful hack.

Thanks :P.

 

Regards,

Sven

On Mon, Jan 30, 2012 at 07:44:40AM -0300, Guillermo Polito wrote:
> FileStream stdout nextPutAll: 'something';crlf.
>
> Works great, but
>
> FileStream stdin next.
>
> Never returns :/.  Whatever I try.
>
> Any idea?
>

This is because no data was received on the standard input stream. Try
typing something followed by <enter> so that the operating system terminal
actually sends some data.

By default, the stdin, stdout, and stderr streams are all in blocking mode
unless you set them otherwise. If you want to set the stdin to nonblocking
mode, see #setNonBlocking in package OSProcess. Note that there is no
"correct" setting for this, it depends on what you are trying to do with
the stream.

HTH,
Dave

On 30 Jan 2012, at 11:44, Guillermo Polito wrote:

> FileStream stdout nextPutAll: 'something';crlf.
>
> Works great, but
>
> FileStream stdin next.
>
> Never returns :/.  Whatever I try.
>
> Any idea?

That is not good, I must admit I only tried #stout, so I did:

$ cat run.sh

#!/bin/bash
script_home=$(dirname $0)
script_home=$(cd $script_home && pwd)
image=$script_home/experimental.image
script=$script_home/run.st
args=$*
vm=$script_home/bin/CogVM
options="-vm-display-null -vm-sound-null"
#echo $vm $options $image $script $args
$vm $options $image $script $args

$ cat run.st
[ FileStream stdin atEnd ] whileFalse: [
   FileStream stdout nextPut: FileStream stdin next ].
!
Smalltalk snapshot: false andQuit: true.

$ cat /tmp/foo.txt
Hello there!
Welcome to Smalltalk.



$ cat /tmp/foo.txt | ./run.sh
Hello there!
Welcome to Smalltalk.



So that seems to work.

HTH,

Sven