add option to change the printing style (#91)

* add option to change the printing style

* format

* additional test

* Update runtests.jl

* Update introduction.md

Author: ranocha

.gitignore

@@ -5,6 +5,7 @@
 **/.ipynb_checkpoints/
 **/*.gif
 **/Manifest.toml
+**/LocalPreferences.toml
 docs/build
 docs/src/contributing.md
 docs/src/license.md

Project.toml

@@ -1,16 +1,18 @@
 name = "RootedTrees"
 uuid = "47965b36-3f3e-11e9-0dcf-4570dfd42a8c"
 authors = ["Hendrik Ranocha <mail@ranocha.de> and contributors"]
-version = "2.13.0"
+version = "2.14.0"
 
 [deps]
 Latexify = "23fbe1c1-3f47-55db-b15f-69d7ec21a316"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+Preferences = "21216c6a-2e73-6563-6e65-726566657250"
 RecipesBase = "3cdcf5f2-1ef4-517c-9805-6587b60abb01"
 Requires = "ae029012-a4dd-5104-9daa-d747884805df"
 
 [compat]
 Latexify = "0.15"
+Preferences = "1.3"
 RecipesBase = "1"
 Requires = "1"
 julia = "1.6"

docs/src/introduction.md

@@ -50,6 +50,17 @@ julia> butcher_representation(t)
 "[[[τ]τ²]τ⁵]"
 ```
 
+You can use the function [`RootedTrees.set_printing_style`](@ref) to change the
+printing style globally. For example,
+```@repl
+using RootedTrees
+t = rootedtree([1, 2, 3, 4, 3, 3, 2, 2, 2, 2, 2])
+RootedTrees.set_printing_style("butcher")
+t
+RootedTrees.set_printing_style("sequence")
+t
+```
+
 There are also some simple plot recipes for [Plots.jl](https://github.com/JuliaPlots/Plots.jl).
 Thus, you can visualize a rooted tree `t` using `plot(t)` when `using Plots`.
 

src/RootedTrees.jl

@@ -5,6 +5,7 @@ module RootedTrees
 using LinearAlgebra: dot
 
 using Latexify: Latexify
+using Preferences: @set_preferences!, @load_preference
 using RecipesBase: RecipesBase
 using Requires: @require
 
@@ -182,8 +183,31 @@ end
 #RootedTree{T<:Integer}(sequence::Vector{T}) = RootedTree{T}(sequence, false)
 
 function Base.show(io::IO, t::RootedTree{T}) where {T}
-    print(io, "RootedTree{", T, "}: ")
-    show(io, t.level_sequence)
+    printing_style = @load_preference("printing_style")
+    if printing_style == "butcher"
+        print(io, butcher_representation(t))
+    else
+        print(io, "RootedTree{", T, "}: ")
+        show(io, t.level_sequence)
+    end
+end
+
+"""
+    RootedTrees.set_printing_style(style::String)
+
+Set the printing style of rooted trees. Possible options are
+
+- "butcher": print the [`butcher_representation`](@ref) of rooted trees
+- "sequence": print the level sequence representation
+
+This system is based on [Preferences.jl](https://github.com/JuliaPackaging/Preferences.jl).
+"""
+function set_printing_style(style::String)
+    if !(style in ("butcher", "sequence"))
+        throw(ArgumentError("Invalid printing style: \"$(style)\""))
+    end
+
+    @set_preferences!("printing_style"=>style)
 end
 
 # comparison

test/runtests.jl

@@ -101,6 +101,47 @@ using Aqua: Aqua
             @test !(new_hash in hashes)
         end
 
+        @testset "printing" begin
+            io = IOBuffer()
+
+            @testset "butcher" begin
+                @test_nowarn RootedTrees.set_printing_style("butcher")
+
+                let t = rootedtree([1])
+                    show(io, t)
+                    @test String(take!(io)) == "τ"
+                    @test butcher_representation(t) == "τ"
+                end
+
+                let t = rootedtree([1, 2, 2, 2, 3])
+                    show(io, t)
+                    @test String(take!(io)) == "[[τ]τ²]"
+                    @test butcher_representation(t) == "[[τ]τ²]"
+                end
+            end
+
+            @testset "sequence" begin
+                @test_nowarn RootedTrees.set_printing_style("sequence")
+
+                let t = rootedtree([1])
+                    show(io, t)
+                    @test String(take!(io)) != "τ"
+                    @test butcher_representation(t) == "τ"
+                end
+
+                let t = rootedtree([1, 2, 2, 2, 3])
+                    show(io, t)
+                    @test String(take!(io)) != "[[τ]τ²]"
+                    @test butcher_representation(t) == "[[τ]τ²]"
+                end
+            end
+
+            @testset "nonsense" begin
+                @test_throws ArgumentError RootedTrees.set_printing_style("nonsense_style")
+                @test_throws ArgumentError RootedTrees.set_printing_style("even_more_nonsense")
+            end
+        end
+
         # see Table 301(I) etc. in butcher2016numerical
         @testset "functions on trees" begin
             t1 = rootedtree([1])