[squeak-dev] Re: Pragmas (Re: The Inbox: Morphic-phite.429.mcz)

Andreas Raab andreas.raab at gmx.de
Mon Apr 26 20:41:44 UTC 2010

On 4/26/2010 1:14 PM, Igor Stasenko wrote:
> On 26 April 2010 22:05, Andreas Raab<andreas.raab at gmx.de>  wrote:
>> On 4/26/2010 11:48 AM, Eliot Miranda wrote:
>>> OK, so Pragma is bad; its historical from "primitive pragma".  But
>>> Annotation doesn't capture the potentially executable flavour of
>>> pragmas.  How about MethodMetaMessage?  (mmm, yum :) )  We could talk
>>> about meta-messages for short. "Add a meta-message that does ..." etc...
>> But "primitive pragma" is every bit as wrong. A pragma is something that
>> gives the compiler information about the code without being code itself.
>> Primitives are't pragmas, primitives are *code* (if you don't believe me,
>> just remove all of them and see how that goes).
>> By definition, a "pragma" is an interface between the code and the compiler,
>> something where the code conveys meta-information to the compiler. For
>> example, this is a pragma (assuming the compiler understands it):
>> foo
>>         <inline: true>
>> bar
>>         <tailcut: true>
>> The first one might instruct the compiler to generate the code for this
>> method inline, the second one to eliminate tail recursion.
>> None of these, however, are pragmas:
>> foo
>>         "Not a pragma since it's not for the compiler"
>>         <preference: 'Foo Preference'
>>           ...
>>         >
>> apiGetWindowFocus
>>         "Not a pragma since it's code"
>>         <apicall: ulong 'GetWindowFocus' (void)>
>> etc. I should also add that before the introduction of the so-called
>> "pragmas" there was only *code* used in the<>  syntax (primitives and FFI
>> calls) and the change to allow non-code entities is something that, although
>> useful, still worries me because of the conceptual issues associated with
>> mixing code and non-code entities. We wouldn't even have that discussion if
>> <>  just meant "code".
> Pragmas are not code, even in old and limited forms, they simply
> contain a meta-information for compiler.

That is *precisely* what I said in the beginning: "A pragma is something 
that gives the compiler information about the code without being code 
itself". Here, I was referring to "<> syntax" which used to be code, and 
now it no longer is. Calling it "pragma" however is just completely and 
utterly wrong in whichever way you look at it.

> If pragmas would be the code, then i expect them to look like code i.e.:

I never claimed that that "pragmas are code". In fact, I said 
*specifically* the opposite.

   - Andreas

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