Invoking return through a function?

[Alberto Riva]

On 10/30/2017 12:23 AM, Rustom Mody wrote:
> On Sunday, October 29, 2017 at 9:52:01 PM UTC+5:30, Rick Johnson wrote:
>> On Sunday, October 29, 2017 at 9:19:03 AM UTC-5, Alberto Riva wrote:
> 
>>> In a language like Lisp
>>
>> Python is nothing like Lisp, and for good reason! Sure, we
>> have a few lispers and functional fanboys who hang around
>> here, and sometimes Rustom can get a little preachy about
>> FP, but mostly, we tolerate the fanboyism -- so long as it's
>> not rabid fanboyism.
> 
> Rick's personal comments are one of the standard entertainments of this list. Enjoy!
> 
> The comments on FP are more problematic:
> 
> - These misconceptions are more widespread than just Rick
> - They are right enough to be hard to refute
> - And wrong enough to cause confusion and misdirection
> - And irrelevant to (threads like) this one
> 
> My super-short rejoiner to the FP-irrelevancy is:
> «If there is one key takeaway from functional programming maybe it should be: "Truth is a function of time" »
> 
> In more detail:
> - Lisp (1960)  was the second functional language; its predecessor was something called Formula Translator — usually shortened to Fortran (c. 1957)
> - By the late 80s, many FPers had begun regard Lisp as a setback for functional programming. [Dont get me wrong: Ive enjoyed Scheme more than any other
> programming language. Its just that conflating Lisp and FP is an error (in 2017)]
> 
> More historical details at http://blog.languager.org/2015/04/cs-history-1.html and sequel
> 
> At a more conceptual level, people dont get that there are two dimensions
> - the apply-lambda axis — usually called functional programming
> - the eval-quote axis — which has precious little to do with FP (and is more relevant to your question)
> 
> These two dimensions of power uniquely coincide in Lisp (Scheme).
> 
> As you correctly (almost) point out
> - Python is very much a lisp… its semantic under-belly
> - However, syntactically its more like C/Java etc in the sense of having a rigid
> fixed-at-language-design-time syntax
> 
> More at http://blog.languager.org/2013/08/applying-si-on-sicp.html
> 
> For a question like macros (syntax-extensions) that sits between the two your
> question is interesting and I am not sure I know how to do it…
> I remember seeing something about this recently but my google-foo is failing me
> at the moment
> 
> However I would look at
> - PEP 263 https://www.python.org/dev/peps/pep-0263/ — Source Code Encodings…
> - Hooking into the codec module https://docs.python.org/3/library/codecs.html
> - hooking into ast module https://docs.python.org/3/library/ast.html
> 
> An old attempt in this direction: http://code.activestate.com/recipes/546539/
> 
> You've already got the moral-hi-horse guys giving you the dope of why this is evil. Swallow if you like. My own lightweight
> suggestion would be that the natural pythonic way of unstructured exit is exceptions. Not as succinct as a tailormade syntax extension. But good enough IMHO
> 
> PS I personally would be interested if you get this (syntax extension) running

Thanks for the interesting reply! But once again: I was not proposing to 
add lisp-style macros to Python; I have no interest in doing that since 
I believe it's pretty much impossible :)

Thanks!

Alberto

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