* math: Make function parentheses optional
It's a bit annoying to use parentheses here because that requires
quoting or escaping.
This allows the parens to be omitted, so
math sin pi
is the same as
math 'sin(pi)'
Function calls have the lowest precedence, so
math sin 2 + 6
is the same as
math 'sin(2 + 6)'
* Add more tests
* Add a note to the docs
* even moar docs
Moar docca
* moar tests
Call me Nikola Testla
Currently a bit limited, unfortunately printf's `%a` specifier is
absolutely unreadable.
So we add `hex` and `octal` with `0x` and `0` prefixes respectively,
and also take a number but currently only allow 16 and 8.
The output is truncated to integer, so scale values other than 0 are
invalid and 0 is implied.
The docs mention this may change.
This was typically overridden by "too many/few arguments", but it's
actually incorrect:
sin(55
has the correct number of arguments to `sin`, but it's lacking
the closing `)`.
Just as `math "bitand(5,3)"` and `math "bitor(6,2)"`.
These cast to long long before doing their thing,
so they truncate to an integer, producing weird results with floats.
That's to be expected because float representation is *very*
different, and performing bitwise operations on floats feels quite useless.
Fixes#7281.
It's now good enough to do so.
We don't allow grid-alignment:
```fish
complete -c foo -s b -l barnanana -a '(something)'
complete -c foo -s z -a '(something)'
```
becomes
```fish
complete -c foo -s b -l barnanana -a '(something)'
complete -c foo -s z -a '(something)'
```
It's just more trouble than it is worth.
The one part I'd change:
We align and/or'd parts of an if-condition with the in-block code:
```fish
if true
and false
dosomething
end
```
becomes
```fish
if true
and false
dosomething
end
```
but it's not used terribly much and if we ever fix it we can just
reindent.
Until now, something like
`math '7 = 2'`
would complain about a "missing" operator.
Now we print an error about logical operators not being supported and
point the user towards `test`.
Fixes#6096
