compatibility with Latexify.jl (#439)

Author: ranocha

Project.toml

@@ -5,6 +5,7 @@ version = "1.0.52"
 [deps]
 CommonEq = "3709ef60-1bee-4518-9f2f-acd86f176c50"
 CommonSolve = "38540f10-b2f7-11e9-35d8-d573e4eb0ff2"
+Latexify = "23fbe1c1-3f47-55db-b15f-69d7ec21a316"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 Markdown = "d6f4376e-aef5-505a-96c1-9c027394607a"
 PyCall = "438e738f-606a-5dbb-bf0a-cddfbfd45ab0"
@@ -14,6 +15,7 @@ SpecialFunctions = "276daf66-3868-5448-9aa4-cd146d93841b"
 [compat]
 CommonEq = "0.2"
 CommonSolve = "0.2"
+Latexify = "0.15"
 PyCall = "1.91"
 RecipesBase = "0.7, 0.8, 1.0, 1.1"
 SpecialFunctions = "0.8, 0.9, 0.10, 1.0"

src/SymPy.jl

@@ -75,6 +75,7 @@ include("lambdify.jl")
 include("patternmatch.jl")
 include("permutations.jl")
 include("plot_recipes.jl")
+include("latexify_recipe.jl")
 
 ##################################################
 

src/latexify_recipe.jl

@@ -0,0 +1,12 @@
+
+using Latexify: Latexify
+
+# Recipe to hook into Latexify.jl's `latexify` function for `Sym`s.
+# We do not use SymPy's `latex` function here since it behaves a bit different
+# from Latexify.jl. Thus, we let Latexify.jl handle everything for the sake of
+# consistency.
+# For example, SymPy doesn't print a multiplication symbol by default while
+# Latexify uses a `"\\cdot"` (unless the keyword argument `cdot=false` is set).
+Latexify.@latexrecipe function _(x::Sym)
+  return string(x)
+end

test/runtests.jl

@@ -17,3 +17,4 @@ include("test-logical.jl")
 #include("test-permutations.jl")
 include("test-physics.jl")
 include("test-external-module.jl")
+include("test-latexify.jl")

test/test-latexify.jl

@@ -0,0 +1,9 @@
+using SymPy
+using Test
+
+@testset "Latexify" begin
+  @vars α
+  @test_nowarn SymPy.Latexify.latexify(- 3/(8*α) + 1/(8*α^2))
+  @test  occursin("\\cdot", SymPy.Latexify.latexify(- 3/(8*α) + 1/(8*α^2), cdot=true))
+  @test !occursin("\\cdot", SymPy.Latexify.latexify(- 3/(8*α) + 1/(8*α^2), cdot=false))
+end