I would rather have them as well defined operators, rather than allowed as parts of identifiers, which would have been more consistent with other things in Julia, like sqrt() and cbrt() using the Unicode symbols as prefix operators, however, the reactions included things like "pry them from my cold, dead hands", plus other people pointed out other cases where the superscript wasn't really doing a ^2 or ^3 operation. That's why I was trying to brainstorm on ways the language could be made tighter, and at least warn about some of the potential cases of programming errors due to the confusion this can cause, without prying the beloved superscripts from their identifiers.
The documentation part is already happening (@Ismael-VC seems to be absolutely full of energy!) On Friday, July 3, 2015 at 9:39:48 AM UTC-4, Tom Breloff wrote: > > I think I've flipped my position back and forth 6 times in the last few > minutes while thinking about this. The mathematician in me wants those > special characters to be well defined operators with the expected > precedence, but the computer scientist in me thinks that's a horribly > stupid idea for reasons that Scott and others have pointed out. The sad > thing is that, whatever the decision, it needs to be done in the core > parsing for it to be useful, so it can't practically be a user-defined > decision (unless of course it becomes a flag you can set when making or > running Julia). > > On that last point... how hard would it be to define certain operators > like the square, etc, that sit within #ifdef blocks in the parser? I guess > even with that ability, you'd potentially be mixing code of both forms > which would be confusing at the very best.... so I guess we have to choose > one. > > At a minimum... gotta document! > > On Thursday, July 2, 2015 at 11:25:00 PM UTC-4, Scott Jones wrote: >> >> Starting in >> https://github.com/JuliaLang/julia/pull/11927#issuecomment-117374003 and >> continuing on in >> https://github.com/JuliaLang/julia/issues/11966#issuecomment-118212265, >> I had raised an issue that can cause confusion to newcomers to Julia, and >> potentially lead to programming errors if one isn't careful. >> There is also the issue of inconsistency within Julia, where certain >> mathematical operations are actually treated as operations, >> and others that look like taking something to a power, i.e. with >> superscripts, are treated as identifiers. >> >> I am *not* suggesting that this should be changed in Julia (people got a >> bit upset with that idea), but rather trying to propose ways >> that the use of superscripts as part of variable names can be made much >> safer in practice. >> >> For example: >> >> julia> cube(x) = x³ >> cube (generic function with 1 method) >> julia> cube(3) # Silly me, I think I'll get 27 >> ERROR: UndefVarError: x³ not defined >> in cube at none:1 >> julia> x³ = 4242 >> julia> cube(3)42 >> >> julia> ∛x³ >>> 3.4760266448864496 >> >> >> Besides documenting this, as @Ismael-VC has suggested, I think that it >> might be useful for the compiler to try to catch some of the cases that >> could actually lead to programming errors. In the above case, the compiler >> could detect that a variable of global scope was being used, along with a >> local variable that is the same except for trailing superscript(s), and >> give a warning. >> Another possible programming error that can occur if one mistakenly >> thought that `³` was performing a cube operation, is that the variable x is >> updated, but the cached cube value in the variable `x³` is not. That could >> also be caught by the compiler. >> >> What do people think? >> Are there any other things that could be done besides documentation, to >> help make using these types of identifiers easier and not error-prone? >> >> >> >>
