How to use 0, 1, 2, 3,... as alias of objects by @objectnames?

[Chenqitrg]

Hi developers,

The

CategoryData.jl/src/prettyprinting.jl

Line 29 in f7d7da8

@objectnames PMFC{2,1,0,1,0,0} 0 1 # without category name

support using integer labels in @objectnames. However, when I try to use it, I cannot figure out how to achieve this goal. For example:

@objectnames PMFC{2,1,0,1,0,0} 0 1

Then directly write

julia> Object{PMFC{2,1,0,1,0,0}}(0)
ERROR: ArgumentError: Unknown PMFC{2, 1, 0, 1, 0, 0} Object 0.

won't work. The following does not work also:

julia> Object{PMFC{2,1,0,1,0,0}}(Symbol(0))
ERROR: ArgumentError: Unknown PMFC{2, 1, 0, 1, 0, 0} Object 0.

When I try to output them:

julia> @show collect(values(Object{PMFC{2,1,0,1,0,0}}))
collect(values(Object{PMFC{2, 1, 0, 1, 0, 0}})) = Object{PMFC{2, 1, 0, 1, 0, 0}}[$(QuoteNode(0)), $(QuoteNode(1))]
2-element Vector{Object{PMFC{2, 1, 0, 1, 0, 0}}}:
 $(QuoteNode(0))
 $(QuoteNode(1))

[Chenqitrg]

I am not sure whether this is because integers are always automatically evaluated:

julia> :σ
:σ
julia> :0
0
julia> typeof(:0)
Int64

[Chenqitrg]

Since Object{SomeCategory} also uses integer variable in default, whether is it in principle forbid naive integer alias? Would using [0], [1] or others avoid ambiguity?

[lkdvos]

Hi @Chenqitrg, after briefly looking at this, I think you are right in the sense that it would be pretty hard to make integers work like that, because we can't dispatch on the Symbol values in the same way. While I could in principle try and support things like Symbol(0), which is not the same as :0, I think that kind of defeats the purpose of having easier names to begin with, so presumably it is better to simply not support this feature. Would that work for you? Note that a simple work-around could be to use something like @objectnames PMFC{2,1,0,1,0,0} _0 _1, or any other letter before to turn the integers into valid symbols.

[Chenqitrg]

Thank you @lkdvos for looking at this. I can avoid this issue using i0, i1 or irr0, irr1.

[lkdvos]

Let's leave this open for now, I need to update the doc string to reflect this