> # WAT: A warning about using collect()?
>
> julia> a = [1:3]
> WARNING: [a] concatenation is deprecated; use collect(a) instead
> in depwarn at deprecated.jl:73
> in oldstyle_vcat_warning at
> /Applications/Julia-0.4.5.app/Contents/Resources/julia/lib/julia/sys.dylib
> in vect at abstractarray.jl:32
> while loading no file, in expression starting on line 0
> 3-element Array{Int64,1}:
> 1
> 2
> 3
Julia used to have matlab-like behavior here but is transitioning to
making
[1:3] == UnitRange{Int}[1:3]
Thus currently the deprecation warning and in Julia 0.5 the new behavior
will be used.
> # WAT: why would a semicolon make the error go away?
>
> julia> a = [1:3;]
> 3-element Array{Int64,1}:
> 1
> 2
> 3
This is another way to do collect but not the preferred one (I forget
the details).
> # This makes sense, I _should_ get a warning every time...
>
> julia> a = [1:3]
> WARNING: [a] concatenation is deprecated; use collect(a) instead
> in depwarn at deprecated.jl:73
> in oldstyle_vcat_warning at
> /Applications/Julia-0.4.5.app/Contents/Resources/julia/lib/julia/sys.dylib
> in vect at abstractarray.jl:32
> while loading no file, in expression starting on line 0
> 3-element Array{Int64,1}:
> 1
> 2
> 3
>
> # WAT: Third time's a charm? We have apparently beaten the interpreter into
> submission :-)
This is a bug: deprecation warning should only show once but often show
several times.
> julia> a = [1:3]
> 3-element Array{Int64,1}:
> 1
> 2
> 3
>
> # By way of comparison, I recently ran some old code and discovered that {}
> is no longer OK:
>
> julia> {}
>
> WARNING: deprecated syntax "{}".
> Use "[]" instead.
> 0-element Array{Any,1}
>
> julia> {}
>
> WARNING: deprecated syntax "{}".
> Use "[]" instead.
> 0-element Array{Any,1}
>
> # And apparently in this case, the interpreter will insist _forever_ ...
>
> julia> {}
>
> WARNING: deprecated syntax "{}".
> Use "[]" instead.
> 0-element Array{Any,1}
Again, the deprecation-warning bug.
