[RPL/2] self compiling ?

[Adrian Blake]

Would you gibe me a simple example of eval()

BERTRAND Joël wrote:
> DEMAINE Benoit-Pierre wrote:
>> Adrian Blake wrote:
>>> What I would like is an example of how it is done.
>> Bertrand asked you what you want.
>>
>> And, you should email me; you should email the list. Otherwise, the
>> replyto get shuffled.
>>
>>> It is easy to create a text file of source code and then issue some
>>> system commands to compile and execute. If this is to be done many times
>>> most of the time and resources is spent with system commands and
>>> compiling. This is especially true if the programs are small and there
>>> are many to be recompiled many times.
>>>
>>> Can RPL/2 do this in a simple manner?
>> Which langage do you use as generator ?
>> what do you want to generate ?
>> from where ?
>>
>> what I did on HP48 was ... the only thing that is possible on this
>> machine: use RPL to generate RPL.
>>
>> But, on a PC, you can go way further, like, use Perl to generate RPL,
>> test it as RPL, then ask the interpreter to generate C code for it, and
>> them querry GCC to optimise the code ...
>>
>> RPL/2 can generate C from RPL, or directly produce a system executable
>> file (that is likely to be linked with some RPL library)
> 
> 	No it cannot.
> 
> 	You can add some external functions written in C (or with all languages 
> that acceots C-type calling procedure). Have a look in 
> src/rplexternals.h and examples/*.rplc. rplc compiler uses macro 
> instructions (over gcc) to produce a regular shared object usable by 
> RPL/2 (loadable by USE intrinsic). If you use librpl, you can launch a 
> RPL/2 _interpreter_ inside a C program (or all languages that uses C 
> calling procedure), but you don't generate any compiled program.
> 
>>> There is a programming language called Erlang which allows the
>>> programmer to modify and add to the executing code. The allows
>>> continuous upgrades without stopping the program.
>> RPL as conveived by HP was not designed to allow "on the fly self
>> modifiable code". And I dont think PC implementation by Bertrand
>> improoves this aspect in any maner.
> 
> 	There is two interpreters in ony program ;-) A text script is evaluated 
> by sequenceur() and an expression is evaluated by evaluation(). A text 
> script is static (because it's half-compiled and some verifications are 
> made before starting execution), but an expression can be dynamic and I 
> think it is possible to write some new intrinsics to modify a running 
> evaluation. I never use this type of features and I don't have any idea 
> about it. Thus, if you have an example...
> 
>> Stil, from within RPL, a program can generate other programs, call them,
>> stop itself ... Bertrand also implemented some labels that will allow
>> special jumps: put a condition at the beginning, and perform
>> conditionnaly a GOTO thing. Still, you will have stack problems.
> 
> 	I have implemented some labels ? Example, please ;-)
> 
>> But, maybe Bertrand introduced some features that would allow some kind
>> of workaround ... if you have used assembly on micro architectures, and
>> if Bertrand did some kind of program counter/pointer, then, you may have
>> lot of fun around it :)
> 
> 	Regards,
> 
> 	JKB
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> 

-- 
Adrian Blake
Molonglo Radio Observatory
University of Sydney
1152 Hoskinstown Rd
Bungendore 2621
ph. 02 62382262  mobile 0407 232 978

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