Implement Base.show (#17)

* Implement Base.show

* Fix ambiguity

* Fix doc

Author: blegat

src/interface.jl

@@ -9,6 +9,8 @@ Society for Industrial and Applied Mathematics, **2012**.
 """
 abstract type AbstractPolynomialBasis end
 
+generators(basis::AbstractPolynomialBasis) = basis.polynomials
+
 function MP.polynomial(coefs::Vector, basis::AbstractPolynomialBasis)
     return MP.polynomial(i -> coefs[i], basis)
 end
@@ -39,7 +41,46 @@ julia> @polyvar x
 (x,)
 
 julia> basis_covering_monomials(ChebyshevBasis, [x^2, x^4])
-ChebyshevBasisFirstKind{Polynomial{DynamicPolynomials.Commutative{DynamicPolynomials.CreationOrder}, Graded{LexOrder}, Float64}}(Polynomial{DynamicPolynomials.Commutative{DynamicPolynomials.CreationOrder}, Graded{LexOrder}, Float64}[1.0, -1.0 + 2.0x², 1.0 - 8.0x² + 8.0x⁴])
+ChebyshevBasisFirstKind([1.0, -1.0 + 2.0x², 1.0 - 8.0x² + 8.0x⁴])
 ```
 """
 function basis_covering_monomials end
+
+function _show(io::IO, mime::MIME, basis::AbstractPolynomialBasis)
+    T = typeof(basis)
+    print(io, nameof(T))
+    print(io, "([")
+    first = true
+    # TODO use Base.show_vector here, maybe by wrapping the `generator` vector
+    #      into something that spits objects wrapped with the `mime` type
+    for g in generators(basis)
+        if !first
+            print(io, ", ")
+        end
+        first = false
+        show(io, mime, g)
+    end
+    return print(io, "])")
+end
+
+function Base.show(
+    io::IO,
+    mime::MIME"text/plain",
+    basis::AbstractPolynomialBasis,
+)
+    return _show(io, mime, basis)
+end
+function Base.show(
+    io::IO,
+    mime::MIME"text/print",
+    basis::AbstractPolynomialBasis,
+)
+    return _show(io, mime, basis)
+end
+
+function Base.print(io::IO, basis::AbstractPolynomialBasis)
+    return show(io, MIME"text/print"(), basis)
+end
+function Base.show(io::IO, basis::AbstractPolynomialBasis)
+    return show(io, MIME"text/plain"(), basis)
+end

src/monomial.jl

@@ -52,6 +52,8 @@ function merge_bases(basis1::MB, basis2::MB) where {MB<:AbstractMonomialBasis}
     return MB(monos), I1, I2
 end
 
+generators(basis::AbstractMonomialBasis) = basis.monomials
+
 """
     struct MonomialBasis{MT<:MP.AbstractMonomial, MV<:AbstractVector{MT}} <: AbstractPolynomialBasis
         monomials::MV

test/fixed.jl

@@ -9,6 +9,8 @@ using DynamicPolynomials
     @test polynomial(one, basis) == 3
     @test basis[1] == 1 - x^2
     @test basis[2] == x^2 + 2
+    @test sprint(show, basis) == "FixedPolynomialBasis([1 - x², 2 + x²])"
+    @test sprint(print, basis) == "FixedPolynomialBasis([1 - x^2, 2 + x^2])"
 end
 @testset "Monomial" begin
     basis = FixedPolynomialBasis([x, x^2])

test/monomial.jl

@@ -10,6 +10,10 @@ using DynamicPolynomials
     @test coefficients(x + 4y, MonomialBasis) == [4, 1]
     @test basis[1] == y
     @test basis[2] == x
+    @test sprint(show, basis) == "MonomialBasis([y, x])"
+    @test sprint(show, MIME"text/print"(), basis) == "MonomialBasis([y, x])"
+    @test sprint(show, MIME"text/plain"(), basis) == "MonomialBasis([y, x])"
+    @test sprint(print, basis) == "MonomialBasis([y, x])"
 end
 @testset "Affine" begin
     # It will be sorted and 1 will be moved at the end
@@ -23,6 +27,8 @@ end
     @test polynomial_type(basis, Int) == polynomial_type(x, Int)
     @test polynomial(i -> i^2, basis) == 9x^2 + 4x * y + y^2
     @test coefficients(x^2 + 4x * y + 9y^2, MonomialBasis) == [9, 4, 1]
+    @test sprint(show, basis) == "MonomialBasis([y², xy, x²])"
+    @test sprint(print, basis) == "MonomialBasis([y^2, x*y, x^2])"
 end
 @testset "merge_bases" begin
     basis1 = MonomialBasis([x^2, y^2])