Example recipe in docs doesn't work

[yha]

The docs at http://makie.juliaplots.org/stable/recipes.html#Full-recipes-with-the-@recipe-macro suggest that this should work (although it's not presented as a complete example in a single block, but in two parts):

# arguments (x, y, z) && theme are optional
@recipe(MyPlot, x, y, z) do scene
    Theme(
        plot_color => :red
    )
end

function plot!(plot::MyPlot)
    # normal plotting code, building on any previously defined recipes
    # or atomic plotting operations, and adding to the combined `plot`:
    lines!(plot, rand(10), color = plot[:plot_color])
    plot!(plot, plot[:x], plot[:y])
    plot
end

There are two trivial problems: plot_color=>:red should be plot_color=:red, and plot! should be fully qualified to extend it (or there should be import AbstractPlotting: plot!).
After fixing these, it still fails:

julia> myplot(1:4,1:4,1:4)
MethodError: no constructors have been defined for Any
plot!(::Combined{myplot,Tuple{UnitRange{Int64},UnitRange{Int64},UnitRange{Int64}}}, ::Type{Any}, ::Attributes, ::Observable{UnitRange{Int64}}, ::Observable{UnitRange{Int64}}) at interfaces.jl:722
plot!(::Type{Any}, ::Combined{myplot,Tuple{UnitRange{Int64},UnitRange{Int64},UnitRange{Int64}}}, ::Observable{UnitRange{Int64}}, ::Vararg{Observable{UnitRange{Int64}},N} where N; kw_attributes::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}) at interfaces.jl:565
plot!(::Type{Any}, ::Combined{myplot,Tuple{UnitRange{Int64},UnitRange{Int64},UnitRange{Int64}}}, ::Observable{UnitRange{Int64}}, ::Observable{UnitRange{Int64}}) at interfaces.jl:564
plot!(::Combined{myplot,Tuple{UnitRange{Int64},UnitRange{Int64},UnitRange{Int64}}}, ::Vararg{Any,N} where N; attributes::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}) at recipes.jl:16
[...]
myplot(::UnitRange{Int64}, ::Vararg{UnitRange{Int64},N} where N) at recipes.jl:12
top-level scope at untitled-100dca0c0f25be3d2c75896832c6a1e9:20

[jlchan]

I can't get the basic example on the docs to work either. For Makie v0.13.9, the following simplified example

using GLMakie

@recipe(MyPlot, x) do scene
    Theme(
        plot_color=:red
    )
end

function Makie.plot!(myplot::MyPlot{<:Tuple{Vector{Float64}}})
    lines!(myplot, rand(10), color = myplot[:plot_color])
    plot!(myplot, myplot[:x])
    myplot
end

gives the error

julia> myplot(1:3)
ERROR: MethodError: no method matching plotsym(::Type{Combined{Any, Tuple{UnitRange{Int64}}}})
Closest candidates are:
  plotsym(::Type{Any}) at /Users/jessechan/.julia/packages/Makie/FXx4Q/src/recipes.jl:4
  plotsym(::Type{var"#s298"} where var"#s298"<:(Arrows{ArgType} where ArgType)) at /Users/jessechan/.julia/packages/Makie/FXx4Q/src/recipes.jl:135
  plotsym(::Type{var"#s298"} where var"#s298"<:(Arc{ArgType} where ArgType)) at /Users/jessechan/.julia/packages/Makie/FXx4Q/src/recipes.jl:135

I'm happy to do a doc PR if I can figure out what's going wrong.

[SimonDanisch]

Yeah I also just noticed that something is broken here... I'll overwork the recipe documentation + add tests over the coming days..
.See also:
#996

[jlchan]

@SimonDanisch thanks! And no worries - I reverse-engineered it using @juliohm's example.

using GLMakie

@Makie.recipe(MyPlot, x,y,z) do scene
    Theme(;
        color = :red,
    )
end

function Makie.plot!(myplot::MyPlot{<:Tuple{<:AbstractVector,<:AbstractVector,<:AbstractVector}})
    lines!(myplot, randn(10), color=myplot[:color])
    plot!(myplot, myplot[:x][], myplot[:y][])
    myplot
end

I can still open a docs PR so there's a working example until the MakieCore refactor finishes?

[jlchan]

Also, it was a bit surprising that @Makie.recipe works but Makie.@recipe does not. Any idea why?

[kongdd]

The trick is that plot! must be imported. This trick should be illustrated in the document.
After that, everything is normal.

using Makie
import Makie: plot, plot!
using GLMakie

## second examples
@recipe(MyPlot, x, y) do scene
  Theme(
    plot_color=:red
  )
end

function plot!(myplot::MyPlot)
  # normal plotting code, building on any previously defined recipes
  # or atomic plotting operations, and adding to the combined `myplot`:
  lines!(myplot, rand(10), color=myplot.plot_color)
  plot!(myplot, myplot.x, myplot.y)
  myplot
end

myplot(1:10, 1:10)