I moved this page to rakudo wiki. A lot of people wanted to add stuff, but gists are not editable. A wiki is a more appropriate place for this kind of stuff. Rakudo wiki is possibly not the best place for it, but for now that will do.
Plus, GitHub gists totally suck when unicode characters are involved. There's also no preview option here. So I'm glad that it is being moved.
Recently Perl 6 got support for various unicode characters (½ ¹ ∞ × ÷, see this link for a full list), but I don't think that we are done. Here is a list of things to think about.
≤ ≥ ≠ (✓ in rakudo/rakudo#1032)
These are more or less obvious and a lot of people have wondered why Perl 6 does not support them yet.
Most probably we should, but there comes a good question – isn't it a bit too much? Well, most probably it's not.
See also: https://irclog.perlgeek.de/perl6/2016-01-09#i_11859391
So that this:
#| This subroutine does the real work
sub do_raw_magic (
Spell $s, #= Which spell to invoke
*%options #= How to invoke it
) {...}Could be written as:
#↓ This subroutine does the real work
sub do_raw_magic (
Spell $s, #← Which spell to invoke
*%options #← How to invoke it
) {...}Why not allow → in pointy blocks?
for ^5 -> $i { say $i } # noo!
for ^5 → $i { say $i } # yeaah!Same goes for lambdas with rw signatures:
for @values <-> $even, $odd { $even ÷= 2 } # noo!
for @values ↔ $even, $odd { $even ÷= 2 } # yeaah!We can also do the same thing with fat arrow:
my %h = 42 => 62 # noo! my %h = 42 ⇒ 62 # yeaah!
¬ for logical not ∧ for and ∨ for or ⊻ for xor
√, ∛ and ∜. Probably as prefix operators. Some argue that we should only add √ given that square root is much more common. I think that we should support all of them for consistency.
⁇ ‼ (✓ in rakudo/rakudo#1029)
⁇ ‼ as a non-texas version of ?? !!. Again, it is pretty simple.
Triangular reduce can have its own unicode character too.
.say for [\+] ^10 .say for [◹+] ^10
Other possible candidates:
- ◿ – it looks more natural but it does not look like its ASCII variant
- ◺ – does not demonstrate the meaning of triangular reduce (or maybe it does? This definitely looks like reduce)
- ◥ – probably OK
U+2301 ELECTRIC ARROW ⌁ for the ~~ operator.
By the way, we can't use ≈ for anything because it brings a confusion about whether it is an approximation or a smartmatch. In that sense ≅ (already supported by Perl 6) and ⌁ will play well together.
≔ as a non-texas version of :=. Pretty obvious.
However, if we are going to add that, then we cannot just leave out ::=, which also has a corresponding unicode character:
⩴ for the ::= operator
The problem is that both are not rendered very nicely by current fonts. ⩴ is also very wide.
‖ for the || operator
Good, but there is no corresponding non-texas version of &&. So I guess that there is no reason to add that right now.
Even though there are ⩵ and ⩶ characters, how are these supposed to look in a fixed-width font?
Although we tend to push unicode adoption, I don't think there's a way to squeeze these things into a width of one character.
In other words: it does not sound like a good idea.
We already have superscripts 4² # Woohoo!, but what about subscripts (*₂)? The choice of unicode characters is pretty much obvious, but what should be the meaning?
There are two options:
- Subscripts could be allowed in variable names so that you can write my $x₁ = 5
- Subscripts could act like array subscripts so that you can write @x₁ which will be equivalent to @x[1]
I vote for the second option, but there are some people who strongly want the first one (I just feel like the second one will be more common and more useful).
If we go for the second one, then there are some other interesting possibilities:
- We can use low asterisk to act like a subscript whatever star: @x⁎₋₁
- Or we can use ₙ as a last index of the array. Like: @xₙ. Perhaps this would make mathematicians happy.
I'd say that in this case we should do both ⁎ and ₙ (because why not).
Another option is to use unicode subscripts as array subscripts if @ sigil is used, but allow subscripts in variable names that have $ sigil. This will probably make all of us happy (but it is going to be so weird…).
The most problematic case was with the code like (* * *)(4, 2). It got better when school-grade math ops were implemented: (* × *)(4, 2), but still, it would be great to have a unicode equivalent to whatever star.
The problem is, there is no obvious character for that.
There are several classes of proposed characters:
- Star-like symbols: ★ ☆ ٭ ✪ ✶ ⭐ ✰ 🌟 and so on and so forth, unicode has so many of those it's not even funny…
- Asterisks: ⊛ ⧆ ⁎ ⁑ ＊ ⁂
- Chars that look like an empty field to fill: 🞅 ◯ ⭕ 🔾 ◌
- Other: ⍰ ⍣
The problem with stars is that they perfectly represent the “star” part, but not so much the “whatever” part. Circles are just circles, they just don't have enough meaning in my opinion. ⍰ is an APL char, is it even appropriate to use it?
There is one more thing: besides Whatever (*) there is also HyperWhatever(**) which perhaps should also get a unicode symbol. This means that not only we have to find one good single character, it would be better if we had a pair of similar characters (e.g. something like ★ and ☆ but better).
⊞ – [+] ⊟ – [-] ⊠ – [×] (or something else?) ⧆ – [*] ⧄ – [/]
But of course there are many other operators that people use all the time. To solve this we can use U+20DE COMBINING ENCLOSING SQUARE [Me] (◌⃞):
÷⃞ – [÷]
However, this has a limit of one character per operator, which means that in some cases you will be forced to fall back to Texas […].
⇔ can be used as a spaceship operator (<=>). But there are other candidates as well:
U+22DA LESS-THAN EQUAL TO OR GREATER-THAN ⋚ U+22DB GREATER-THAN EQUAL TO OR LESS-THAN ⋛ U+1F680 ROCKET 🚀
The last one is a joke, of course.
(suggested by teatime)
∨ for || (unicode character name LOGICAL OR) ∧ for && (unicode character name LOGICAL AND)
⇢ ⎯→
say 2‥5
There is an idea that 🙼 (VERY HEAVY SOLIDUS) can produce a FatRat, as in:
sub infix:<🙼> { FatRat.new: $^a, $^b }± can be used to create ranges. Example:
sub infix:<±> { Range.new: $^a - $^b, $a + $b };
say 5 ± 2 # OUTPUT: «3..7»
say 4 ~~ 5 ± 2 # OUTPUT: «True»
say 0 ~~ 5 ± 2 # OUTPUT: «False»
@smls You're absolutely right! I changed the gist accordingly. Thank you for your comment.
That being said, I slightly disagree with your point №3. Sure, there's no need to artificially search for unicode versions of everything, but there are exceptions. The reason why this gist discusses possibilities for Whatever is because:
my $x = * * *. It got better once we got × (my $x = * × *), but even then a unicode version of whatever star can improve readability significantly.Indeed, any replacement for whatever star is not going to fit your criteria, but… we still need it :)