Peter Goodall (Nov 16 2021 at 04:09): Peter Goodall (Nov 16 2021 at 04:09):I can't find any contradiction in Julia - Allowed Variable Names
\ttzero = U+1D7F6
Sukera (Nov 16 2021 at 08:08):seems like a parsing error
Sebastian Pfitzner (Nov 16 2021 at 08:56):number-like chars are usually not allowed to start an identifier
Sebastian Pfitzner (Nov 16 2021 at 08:56):so a𝟶 parses fine
Sukera (Nov 16 2021 at 08:59):right, \ttone is not a letter
julia> '𝟷'
'𝟷': Unicode U+1D7F7 (category Nd: Number, decimal digit)
maybe a string macro for creating your "bitstrings" is better suited?
Peter Goodall (Nov 16 2021 at 18:34):@Sebastian Pfitzner That looks like what the parser was complaining about, but the documentation says:
Allowed Variable Names
Variable names must begin with a letter (A-Z or a-z), underscore, or a subset of Unicode code points greater than 00A0
And then (IMHO) it mumbles a bit...
Sebastian Pfitzner (Nov 16 2021 at 18:34):It does say "Subsequent characters may also include ! and digits (0-9 and other characters in categories Nd/No)", which kinda implies that those are not allowed at the start
Peter Goodall (Nov 16 2021 at 18:38):My lack of unicode experience is showing... Unicode Categories are now decrypted for me.
List of Unicode Characters of Category “Decimal Number”
Peter Goodall (Nov 16 2021 at 18:42):Sort of happy with this:
> @enum 𝔹 zero one
> ⊻(a::𝔹, b::𝔹) = a == b ? zero : one
⊻ (generic function with 1 method)
> @show (zero ⊻ one, one ⊻ one)
(zero ⊻ one, one ⊻ one) = (one, zero)
you're kind of punning the functions zero and one though
Sukera (Nov 16 2021 at 18:55):julia is very unicode aware
Peter Goodall (Nov 16 2021 at 19:42):@Sukera
you're kind of punning the functions
zeroandonethough
I'm not sure what you mean by functions. I thought I was defining a data-type with two elements zero and one, which I am giving behavior by defining the function ⊻.
Cheers...
Sebastian Pfitzner (Nov 16 2021 at 19:47):that will locally shadow the one/zero functions that Base exports
Sebastian Pfitzner (Nov 16 2021 at 19:47):which isn't necessarily bad though
Peter Goodall (Nov 16 2021 at 19:48):If do:
julia> typeof(zero)
Enum 𝔹:
zero = 0
one = 1
The enumeration, to my mind - coincidentally, assigns them integers corresponding to their 'emotional' value.
This works as well:
> @enum 𝔹 zero=3 one=7
> ⊻(a::𝔹, b::𝔹) = a == b ? zero : one
> @show (zero ⊻ one, one ⊻ one)
(zero ⊻ one, one ⊻ one) = (one, zero)
I could have given them boolean values - which I might like to do?
Peter Goodall (Nov 16 2021 at 19:52):oh boy...
Mason Protter (Nov 16 2021 at 19:53):Not sure what to say other than to re-iterate what Sebastian said. one and zero are functions exported by Base
julia> zero(Float64)
0.0
julia> one(Complex{Rational{Int}})
1//1 + 0//1*im
When you do
@enum 𝔹 zero one
you're locally changing the meaning of those identifiers to be what your Enum defines
Mason Protter (Nov 16 2021 at 19:53):Which is fine
Mason Protter (Nov 16 2021 at 19:53):And you can still access Base.one and Base.zero by qualifying the names
Mason Protter (Nov 16 2021 at 19:54):julia> @enum 𝔹 zero one
julia> zero(Float64)
ERROR: MethodError: objects of type 𝔹 are not callable
Stacktrace:
[1] top-level scope
@ REPL[5]:1
julia> Base.zero(Float64)
0.0
I made a joke - which I couldn't see :-))
Peter Goodall (Nov 16 2021 at 19:56):Is there a way of creating a type in Julia, which has a set of elements, without using @enum?
Though now all you kind people have shown me what I was really doing, I think for the purposes of this exercise, I have something that works.
Mason Protter (Nov 16 2021 at 20:01):You could use an inner constructor to reject invalid data
julia> struct 𝔹²
x::Int
y::Int
𝔹²(x,y) = if (x,y) ∈ Iterators.product((0,1), (0,1))
new(x,y)
else
throw("Invalid booleans $((x,y))")
end
end
julia> 𝔹²(1, 0)
𝔹²(1, 0)
julia> 𝔹²(0, 0)
𝔹²(0, 0)
julia> 𝔹²(0, 2)
ERROR: "Invalid booleans (0, 2)"
Stacktrace:
[1] 𝔹²(x::Int64, y::Int64)
@ Main ./REPL[8]:7
[2] top-level scope
@ REPL[11]:1
Last updated: Oct 02 2023 at 04:34 UTC