Add fallback for pretty_print (#244)

* Add fallback for pretty_print

Fixes #233

* Fix a test

* Bump patch version

* Remove testing Julia 1.2 and 1.3, and add  Julia 1.4

.travis.yml

@@ -6,8 +6,7 @@ os:
 
 julia:
     - 1.0
-    - 1.2
-    - 1.3
+    - 1.4
     - nightly
 
 notifications:

Project.toml

@@ -1,7 +1,7 @@
 name = "TaylorSeries"
 uuid = "6aa5eb33-94cf-58f4-a9d0-e4b2c4fc25ea"
 repo = "https://github.com/JuliaDiff/TaylorSeries.jl.git"
-version = "0.10.4"
+version = "0.10.5"
 
 [deps]
 InteractiveUtils = "b77e0a4c-d291-57a0-90e8-8db25a27a240"

src/printing.jl

@@ -19,6 +19,30 @@ function superscriptify(n::Int)
 end
 
 
+#  Fallback
+function pretty_print(a::Taylor1)
+    # z = zero(a[0])
+    var = _params_Taylor1_.var_name
+    space = string(" ")
+    bigO = bigOnotation[end] ?
+        string("+ 𝒪(", var, superscriptify(a.order+1), ")") :
+        string("")
+    # iszero(a) && return string(space, z, space, bigO)
+    strout::String = space
+    ifirst = true
+    for i in eachindex(a)
+        monom::String = i==0 ? string("") : i==1 ? string(" ", var) :
+            string(" ", var, superscriptify(i))
+        @inbounds c = a[i]
+        # c == z && continue
+        cadena = numbr2str(c, ifirst)
+        strout = string(strout, cadena, monom, space)
+        ifirst = false
+    end
+    strout = strout * bigO
+    strout
+end
+
 function pretty_print(a::Taylor1{T}) where {T<:NumberNotSeries}
     z = zero(a[0])
     var = _params_Taylor1_.var_name

test/onevariable.jl

@@ -5,7 +5,13 @@ using TaylorSeries
 
 using Test
 using LinearAlgebra, SparseArrays
-eeuler = Base.MathConstants.e
+const eeuler = Base.MathConstants.e
+
+# This is used to check the fallack of pretty_print
+struct SymbNumber <: Number
+    s :: Symbol
+end
+Base.iszero(::SymbNumber) = false
 
 @testset "Tests for Taylor1 expansions" begin
     ta(a) = Taylor1([a,one(a)],15)
@@ -521,6 +527,10 @@ eeuler = Base.MathConstants.e
     @test Taylor1{Float64}(false) == Taylor1([0.0])
     @test Taylor1{Int}(true) == Taylor1([1])
     @test Taylor1{Int}(false) == Taylor1([0])
+
+    # Test fallback pretty_print
+    st = Taylor1([SymbNumber(:x₀), SymbNumber(:x₁)])
+    @test string(st) == " SymbNumber(:x₀) + SymbNumber(:x₁) t + 𝒪(t²)"
 end
 
 @testset "Test `inv` for `Matrix{Taylor1{Float64}}``" begin