Re: [Python-ideas] Left arrow and right arrow operators
On 3/15/19 9:02 PM, francismb wrote: > And the operator is the function.exactly, function application/call ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
Re: [Python-ideas] Left arrow and right arrow operators
Hi Nick, On 3/12/19 3:57 PM, Nick Timkovich wrote: > The onus is on you > to positively demonstrate you require both directions, not him to > negatively demonstrate it's never required. >From Calvin I just wanted to have some examples where he sees a use for swapping operands (nothing to be demonstrated :-) ). But I really just wanted to talk some *visual asymmetric form* that could be used as operator for potentially asymmetric operations and thought that the arrow could be one of this. So you're correct one should discuss with *form* could potentially be wider accepted/work. The debate on this is going on the thread: "Why operators are useful". Regards, --francis ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
Re: [Python-ideas] Left arrow and right arrow operators
On 3/13/19 7:44 PM, David Teresi wrote: > `->` would not be ambiguous in the proposed cases, but it does already > mean something elsewhere in the language as of 3.5: > > def concat(a: str, b: str) -> str: > return a + b > > This could potentially cause confusion (as with the % operator being > used for modulo as well as string formatting). IMHO in that context the asymmetry is still there: (a: str, b: str) -> str And the operator is the function. Regards, --francis ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
Re: [Python-ideas] Left arrow and right arrow operators
On 3/13/19 1:44 PM, David Teresi wrote:
`->` would not be ambiguous in the proposed cases, but it does already
mean something elsewhere in the language as of 3.5:
def concat(a: str, b: str) -> str:
return a + b
This could potentially cause confusion (as with the % operator being
used for modulo as well as string formatting).
But by that logic, the colon is also ambiguous: the colon
is used to indicate a dictionary entry, as in {a : str}.
Given the radically difference contexts in which the tokens
in question occur, I don't think that this is an issue (then
again, I've never designed a language as widely consumed as
Python).
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Re: [Python-ideas] Left arrow and right arrow operators
`->` would not be ambiguous in the proposed cases, but it does already mean something elsewhere in the language as of 3.5: def concat(a: str, b: str) -> str: return a + b This could potentially cause confusion (as with the % operator being used for modulo as well as string formatting). On Tue, Mar 12, 2019 at 10:58 AM Nick Timkovich wrote: > > In general, there is lots of code out in the wild that can't be updated for > whatever reason, e.g. the person that knows Python left and it needs to > continue to work. Weak argument, but cost-benefit I think it comes out ahead. > In your example there isn't a reason I can tell why swapping the operands > isn't what should be done as Calvin mentioned. The onus is on you to > positively demonstrate you require both directions, not him to negatively > demonstrate it's never required. > > I suggest you confine your proposal to `->` only, as it's currently illegal > syntax. You would also want the reflected `__r*__` equivalent of `__arrow__` > or `__rarrow__` (`__rrarrow__` if you also need the left-arrow...) > > Perhaps broadening the use of it, functions may be able to use it as a pipe > operator, e.g. Elixir: > https://elixir-lang.org/getting-started/enumerables-and-streams.html#the-pipe-operator > > On Mon, Mar 11, 2019 at 2:58 PM francismb wrote: >> >> Hi Greg, >> >> On 3/9/19 1:42 AM, Greg Ewing wrote: >> > Do you really want >> > to tell them that all their code is now wrong? >> Of course not, at least not so promptly. But, would it be still a >> problem if the update to a new version (let say from 3.X to next(3.X)) >> is done through some kind of updater/re-writer/evolver. In that case the >> evolver could just add the blanks. What do you think ? Could it work? >> >> Thanks in advance! >> --francis >> ___ >> Python-ideas mailing list >> Python-ideas@python.org >> https://mail.python.org/mailman/listinfo/python-ideas >> Code of Conduct: http://python.org/psf/codeofconduct/ > > ___ > Python-ideas mailing list > Python-ideas@python.org > https://mail.python.org/mailman/listinfo/python-ideas > Code of Conduct: http://python.org/psf/codeofconduct/ ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
Re: [Python-ideas] Left arrow and right arrow operators
In general, there is lots of code out in the wild that can't be updated for whatever reason, e.g. the person that knows Python left and it needs to continue to work. Weak argument, but cost-benefit I think it comes out ahead. In your example there isn't a reason I can tell why swapping the operands isn't what should be done as Calvin mentioned. The onus is on you to positively demonstrate you require both directions, not him to negatively demonstrate it's never required. I suggest you confine your proposal to `->` only, as it's currently illegal syntax. You would also want the reflected `__r*__` equivalent of `__arrow__` or `__rarrow__` (`__rrarrow__` if you also need the left-arrow...) Perhaps broadening the use of it, functions may be able to use it as a pipe operator, e.g. Elixir: https://elixir-lang.org/getting-started/enumerables-and-streams.html#the-pipe-operator On Mon, Mar 11, 2019 at 2:58 PM francismb wrote: > Hi Greg, > > On 3/9/19 1:42 AM, Greg Ewing wrote: > > Do you really want > > to tell them that all their code is now wrong? > Of course not, at least not so promptly. But, would it be still a > problem if the update to a new version (let say from 3.X to next(3.X)) > is done through some kind of updater/re-writer/evolver. In that case the > evolver could just add the blanks. What do you think ? Could it work? > > Thanks in advance! > --francis > ___ > Python-ideas mailing list > Python-ideas@python.org > https://mail.python.org/mailman/listinfo/python-ideas > Code of Conduct: http://python.org/psf/codeofconduct/ > ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
Re: [Python-ideas] Left arrow and right arrow operators
Hi Greg, On 3/9/19 1:42 AM, Greg Ewing wrote: > Do you really want > to tell them that all their code is now wrong? Of course not, at least not so promptly. But, would it be still a problem if the update to a new version (let say from 3.X to next(3.X)) is done through some kind of updater/re-writer/evolver. In that case the evolver could just add the blanks. What do you think ? Could it work? Thanks in advance! --francis ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
Re: [Python-ideas] Left arrow and right arrow operators
francismb wrote: It is may be how now it is, but means that it needs to be always like this? Yes, as long as you care about not breaking existing code. While you may be in the habit of always leaving a space between '<' and '-', others may have different styles. Do you really want to tell them that all their code is now wrong? -- Greg ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
Re: [Python-ideas] Left arrow and right arrow operators
Hi Oleg, On 3/3/19 4:06 PM, Oleg Broytman wrote: >You cannot create operator ``<-`` because it's currently valid > syntax: > > 3 <- 2 > > is equivalent to > > 3 < -2 Yes, its a good point, but for me it's not the same '<-' and '< -' due (n)blanks in between. It is may be how now it is, but means that it needs to be always like this? Isn't Python not already blank(s)/indentation aware? or it's just a grammar NO GO? Thanks in advance! --francis ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
Re: [Python-ideas] Left arrow and right arrow operators
Hi fhsxfhsx, On 3/4/19 5:56 AM, fhsxfhsx wrote: > Could you explain why do you prefer this operator than `+`? Well yes, because of the asymmetric operation done underneath (merging dicts is not symmetric). The asymmetry is explicit in the symbol. Not implicit from the documentation you need to know/read for + (in the case proposed for dictionaries). Regards, --francis ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
Re: [Python-ideas] Left arrow and right arrow operators
Hi Calvin, On 3/4/19 2:09 PM, Calvin Spealman wrote: > I don't like the idea of arrows in both directions when you can just swap > the operands instead Well you saw just to examples of contexts (dict and bool). Could you imagine a context where swapping cannot be done and thus there is a need for left- and right arrow? Thanks in advance! --francis ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
Re: [Python-ideas] Left arrow and right arrow operators
Hi Todd, On 3/4/19 2:18 PM, Todd wrote: > What is the operator supposed to do? this should depend on what you want to do, the type, the context. How to you would want to use it ? do you see a context where the symbols make meaning to you? Thanks in advance! --francis ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
Re: [Python-ideas] Left arrow and right arrow operators
What is the operator supposed to do?
On Sun, Mar 3, 2019, 09:52 francismb wrote:
> Hi,
> the idea here is just to add the __larrow__ and __rarrow__ operators for
> <- and ->.
>
>
> E.g. of use on dicts :
> >>> d1 = {'a':1, 'b':1 }
> >>> d2 = {'a':2 }
> >>> d3 = d1 -> d2
> >>> d3
> {'a':1, 'b':1 }
>
> >>> d1 = {'a':1, 'b':1 }
> >>> d2 = {'a':2 }
> >>> d3 = d1 <- d2
> >>> d3
> {'a':2, 'b':1 }
>
> Or on bools as Modus Ponens [1]
>
> Or your idea/imagination here :-)
>
>
>
> Regards,
> --francis
>
> [1] https://en.wikipedia.org/wiki/Modus_ponens
>
>
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Re: [Python-ideas] Left arrow and right arrow operators
I don't like the idea of arrows in both directions when you can just swap
the operands instead
On Sun, Mar 3, 2019 at 9:52 AM francismb wrote:
> Hi,
> the idea here is just to add the __larrow__ and __rarrow__ operators for
> <- and ->.
>
>
> E.g. of use on dicts :
> >>> d1 = {'a':1, 'b':1 }
> >>> d2 = {'a':2 }
> >>> d3 = d1 -> d2
> >>> d3
> {'a':1, 'b':1 }
>
> >>> d1 = {'a':1, 'b':1 }
> >>> d2 = {'a':2 }
> >>> d3 = d1 <- d2
> >>> d3
> {'a':2, 'b':1 }
>
> Or on bools as Modus Ponens [1]
>
> Or your idea/imagination here :-)
>
>
>
> Regards,
> --francis
>
> [1] https://en.wikipedia.org/wiki/Modus_ponens
>
>
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Re: [Python-ideas] Left arrow and right arrow operators
I wonder if it is necessary to add two new operators, and for me, "arrow
operator" is not clearer than `+`. Could you explain why do you prefer this
operator than `+`?
Also -> is a symbol of propositional logic, like ∧ and ∨ , do we also need
these operators as well?
At 2019-03-03 22:46:24, "francismb" wrote:
>Hi,
>the idea here is just to add the __larrow__ and __rarrow__ operators for
><- and ->.
>
>
>E.g. of use on dicts :
d1 = {'a':1, 'b':1 }
d2 = {'a':2 }
d3 = d1 -> d2
d3
>{'a':1, 'b':1 }
>
d1 = {'a':1, 'b':1 }
d2 = {'a':2 }
d3 = d1 <- d2
d3
>{'a':2, 'b':1 }
>
>Or on bools as Modus Ponens [1]
>
>Or your idea/imagination here :-)
>
>
>
>Regards,
>--francis
>
>[1] https://en.wikipedia.org/wiki/Modus_ponens
>
>
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Re: [Python-ideas] Left arrow and right arrow operators
On Sun, Mar 03, 2019 at 03:46:24PM +0100, francismb wrote: > Hi, > the idea here is just to add the __larrow__ and __rarrow__ operators for > <- and ->. You cannot create operator ``<-`` because it's currently valid syntax: 3 <- 2 is equivalent to 3 < -2 > Regards, > --francis Oleg. -- Oleg Broytmanhttps://phdru.name/p...@phdru.name Programmers don't die, they just GOSUB without RETURN. ___ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/
[Python-ideas] Left arrow and right arrow operators
Hi,
the idea here is just to add the __larrow__ and __rarrow__ operators for
<- and ->.
E.g. of use on dicts :
>>> d1 = {'a':1, 'b':1 }
>>> d2 = {'a':2 }
>>> d3 = d1 -> d2
>>> d3
{'a':1, 'b':1 }
>>> d1 = {'a':1, 'b':1 }
>>> d2 = {'a':2 }
>>> d3 = d1 <- d2
>>> d3
{'a':2, 'b':1 }
Or on bools as Modus Ponens [1]
Or your idea/imagination here :-)
Regards,
--francis
[1] https://en.wikipedia.org/wiki/Modus_ponens
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