Le��mer. 11 sept. 2019 ����10:40, Serge Stinckwich <serge.stinckwich@gmail.com> a ��crit��:

On Wed, Sep 11, 2019 at 2:14 AM Gabriel Cotelli <g.cotelli@gmail.com> wrote:

Looks like Christmas season opened early this year :)

Jokes aside, I'm in favor of changing some of the characters we use for binary selectors to allow it to be used in keyword/unary messages.

I'll include % in that list. For me its more useful as a way to create percentages ( 5 % ) than to be used as a binary message for keeping an ugly name from C-like languages.

• �� is middle dot and it's used in some math operations AFAIR
• �� is used in math also (it's used as the multiplication sign for scalars, cross product for vectors and cartesian product for sets)

One thing that would be really cool is that we can use the full power of Unicode in methods/class names. Projects like polymath and DSLs can clearly take advantage of that. Some examples I've just invented, but can be supported:

• ��� from: 1 to: 5 do: [:i | i + i squared ]

• 1 ��� 3

• ��� anyIn: #( 1 2 4) such: [:x | x isPrime ]��

• ��� includes: 1

Yes I would like to have something like that for PolyMath :-)

Is it possible to use Unicode characters for identifiers already ?

I working on the port of : https://github.com/len/Domains

to Pharo. The author modify the Cuis parser, so he can do things like that :

"��� is used for direct sums, ��� for tensor products, �� for cartesian product, direct product of groups, ring products, and in general for categorical products."

Of course we want to be able to use those selectors:�� ����� ��� etc...

Not using those selectors in core image is one thing, forbiding their usage for every package is another thing

Concerning the selectors with more than 2 characters, there are two examples in use in Squeak

==> logical implication (I use it a lot when writing tests cases)

<=> space ship operator

/// has been used in the past (but is rather deprecated)

What is questionable is cultural acceptance of universal meaning of a Symbol

<=> could have meant logical equivalence, but it would be pointless, because = (and == thanks to singleton) are already equivalence.

It has been expunged from Pharo to my regrets, because it is

- beautifully self defined as < = >

- culturally legitimate

- the art of original author (Travis Griggs)

There is no sacred cow, but respect of author has a value for me.

It's sure that every binary selector might be questionable, at least in core image.

For application, you never know (think DSL) we can create a lot of not completely inaesthetic ASCII styles

<|>�� ><���� <+> <->�� /+/�� |*|

For example +/- could be used for interval arithmetic (if we don't want to pay the burden of typing unicode, which ain't easy)

/\�� \/�� intersection and union

|\| the Nicolas operator - I didn't fin a usage for it yet ;)

etc...

So why would one want to forbid them?

For ? and ! I do not foresee elegant usage as binary, but would not miss them as regular letters eithers.

It means accepting huge???�� - understand isReallyHuge :)

huge?:or!:???and: which are not less questionable.

Ideally, it should be really easy to define one's own syntax in any class (already possible with own compiler/parser/scanner/whatever), or maybe any method

I find that it's somehow more complex with the well engineered new Compiler than it was with the very hackish legacy one, but that's a detail.

and also define ^ as a binary method:

"The ^ (hat) operator is used for exponentiation as well as conjugation by group elements, and for creating free modules of tuples and matrices."

I'm not sure this is a good idea, because ^ is used also to return values.

There is no ambiguity for ^ and i have proposed that in Squeak years ago, it's a very simple change (here for legacy Compiler)

http://source.squeak.org/inbox/Compiler-nice.280.diff

The only argument against it is that omitting the point ending last but one sentence would not be detected as invalid syntax

������ self doThis.

������ ^self doThat

versus

������ self doThis

������ ^self doThat

To address this concern, we could have rules concerning the formatting:

normally we would write

������ self doThis ^ self doThat

or eventually if on several lines, we would generally indent

������ self doThis

�������������� ^ self doThat

An unusual formatting is a code smell IMO

And in fact, this is not much different from un-detecting when we send a message #self when forgetting the point

������ self doThis

������ self doThat

������ self doThis self doThat.

A+

--

Serge Stinckwic

h

Int. Research Unit

��on Modelling/Simulation of Complex Systems (UMMISCO)

Sorbonne University

��(SU)

French National Research Institute for Sustainable Development (IRD)

U

niversity of Yaound�� I, Cameroon

"Programs must be written for people to read, and only incidentally for machines to execute." https://twitter.com/SergeStinckwich