Re: Objective-C - Smalltalk bridge

[Marcel Weiher]

On 12 May 2005, at 23:37, Stefan Urbanek wrote:
>


> Issues I had:
> - the bridge requires readline and ncurses - can be that eliminated
> somehow?
> - the program ended on Smalltalk readline
> - how can I get ObjC proxy for a Smalltalk object? I was not able  
> to say
> anything about a result of an execution. I want to do someting like:
>
>     Smalltalk        *smalltalk; /* say this exists */
>     NSMutableArray   *array; /* this exists too */
>     ...
>     result = [smalltalk execute:@"1+1"];
>     [array addObject:result];
>     NSLog(@"Added number %i", [result intValue]);
>
> Also ... how can I reference ObjectiveC objects from Smalltalk?  
> Would it
> be possible to give more examples?

With Objective-Smalltalk, you get that, but without a bridge or proxies:

marcel@tpol[marcel]cat > stexec.m
#import <MPWTalk/MPWStCompiler.h>

int main( int argc, char *argv[] ) {
    id pool = [NSAutoreleasePool new];
    id eval = [MPWStCompiler new];
    id result = [eval evaluate:@"1+1."];
    NSLog(@"result: %d",[result intValue]);
    exit(0);
    return 0;
}
marcel@tpol[marcel]cc -O -Wall -o stexec stexec.m -framework MPWTalk - 
framework MPWFoundation -framework Foundation
stexec.m: In function 'main':
stexec.m:4: warning: unused variable 'pool'
marcel@tpol[marcel]./stexec
2005-05-21 13:11:34.516 stexec[714] result: 2
marcel@tpol[marcel]

What is Objective-Smalltalk?  In a nutshell:  a Smalltalk syntax for  
the Objective-C runtime + language semantics.  So there are no  
proxies and no two runtimes that have to talk to each other.  This  
allows Objective-ST to be very compact, currently only around 1.5  
KLOC, with several hundred of those being the unit tests.  That  
includes a basic compiler/interpreter (compiler for the syntax,  
'interpreter' for running the returned Objective-C objects that  
represent a script/method) ready for integration.  It is still early  
days, but good enough to use in some of my shipping products.

I am currently working on a (very primitive) little method browser:

Another part:  stsh, a smalltalk shell, both for interactive and  
scripting use.

marcel@tpol[stsh]stsh
> 3 + 4
7
> last * 6
42
> theAnswer := last
42
> theAnswer class
NSCFNumber
> context scanner setIntClass:NSDecimalNumber
> 1 class
NSDecimalNumber
>

--------------  pdfdump.stsh ---------------
#!/usr/local/bin/stsh
filename := args objectAtIndex:1
stdout print: 'pdfdump of: '
stdout println: filename

data := NSData dataWithContentsOfMappedFile: filename
pdf := (MPWPDFFile alloc initWithPdfData:data ) autorelease
pages := pdf pages
stdout writeObject: pages count
stdout println: ' pages'

stdout writeObject:pages

contentStreams := pages collect contentStreams
allStreams := contentStreams collect lastObject
allContent := allStreams collect stringValue
stdout println: 'got allContent'
stdout writeObject:allContent
---------------  pdfdump.stsh -------------------


In the works:  a gcc front end, though that is *quite* a struggle.   
Doing a JIT might be simpler... :-(

Cheers,

Marcel