... of @code_warntype output.
I was reading
https://en.wikibooks.org/wiki/Introducing_Julia/Types#Investigating_types
and I came across the following code, described as "not very elegant":
level = 0
function showtypetree(subtype)
global level
subtypelist = filter(asubtype -> asubtype != Any, subtypes(subtype))
if length(subtypelist) > 0
println("\t" ^ level, subtype)
level += 1
map(showtypetree, subtypelist)
level -= 1
else
println("\t" ^ level, subtype)
end
end
showtypetree(Number)
Being unable to leave well enough alone, I decided to try to make it more
elegant. After replacing the inelegant global variable with a nested
function, I first noticed that the function returns '0', which is ugly. So,
the increment operators return a value, which is unfortunate (any reason
there's no increment with doesn't do that?) and the two branches of the if
return different types. A special 'ignore' function patches that. map also
builds and returns a value that's discarded. In OCaml we'd use an 'iter'
instead of 'map', but Julia's 'for' can be a one-liner too. I left the
print alone even though there's no need to repeatedly build those strings
(print_nchars_before is easy) .In the end I got here
ignore{T<:Any}(value::T)::Void = return
function showtypetree(subtype::DataType)::Void
level::Int64 = 0
function nested(st::DataType)::Void
subtypelist = filter(asubtype -> asubtype != Any, subtypes(st))
if length(subtypelist) > 0
println("\t" ^ level, st)
level += 1
for s in subtypelist nested(s) end
ignore(level -= 1)
else
println("\t" ^ level, st)
end
end
nested(subtype)
end
I still notice that when I do @code_warntype showtypetree(Number), I get
some 'red', notably, level is shown as Core.Box, even though I explicitly
type it. Is there some way to reduce the red in the @code_warntype for this
function? Here's what I get in 0.6.0-dev.749
julia> @code_warntype showtypetree(Number)
Variables:
#self#::#showtypetree
subtype::Type{Number}
level::Core.Box
nested::Core.Box
Body:
begin
level::Core.Box = $(Expr(:new, :(Core.Box)))
nested::Core.Box = $(Expr(:new, :(Core.Box)))
SSAValue(0) = Main.Void
(Core.setfield!)(level::Core.Box,:contents,0)::Int64 # line 3:
SSAValue(1) = $(Expr(:new, :(Main.#nested#2), :(level), :(nested)))
(Core.setfield!)(nested::Core.Box,:contents,SSAValue(1))::#nested#2 #
line 16:
return
(Base.convert)(SSAValue(0),((Core.getfield)(nested::Core.Box,:contents)::Any)(subtype::Type{Number})::Any)::Void
end::Void
and I'm not sure how to remove the red and make the code more elegant.
Ideas?
