Even smarter printing of complex coefficients

Author: gustaphe

src/show.jl

@@ -159,6 +159,15 @@ function printproductsign(io::IO, pj::T, j, mimetype) where {T}
     (showone(T) || pj != one(T)) &&  print(io, showop(mimetype, "*"))
 end
 
+function printproductsign(io::IO, pj::T, j, mimetype) where {T<:Complex}
+    j == 0 && return
+    (a,b) = reim(pj)
+    !iszero(a) && !iszero(b) && return # parentheses inserted, no * needed
+    !iszero(a) && return printproductsign(io, a, j, mimetype)
+    print(io, showop(mimetype, "*"))
+end
+
+
 # show a single term
 # Other types can overload Polynomials.printcofficient with a mimetype
 # or Base.show_unquoted(io, pj, indent, prec)
@@ -210,7 +219,7 @@ function printcoefficient(io::IO, pj::S, j, mimetype) where {T,S <: Complex{T}}
     hasimag = !iszero(b) || isnan(b) || isinf(b)
 
     if hasreal && hasimag
-        print(io, "(")
+        iszero(j) || print(io, "(")
         print(io, a)
 
         # print b
@@ -232,7 +241,7 @@ function printcoefficient(io::IO, pj::S, j, mimetype) where {T,S <: Complex{T}}
         end
 
         print(io, imagsymbol(mimetype))
-        print(io, ")")
+        iszero(j) || print(io, ")")
 
     elseif hasreal
 

test/Poly.jl

@@ -286,15 +286,16 @@ p = Poly([1.0, 2.0, 3.0, 1.0])
 p = Poly([1, im])
 @test repr(p) == "Poly(1 + im*x)"
 p = Poly([1+im, 1-im, -1+im, -1 - im])# minus signs
-@test repr(p) == "Poly((1 + 1im) + (1 - 1im)*x - (1 - 1im)*x^2 - (1 + 1im)*x^3)"
+@test repr(p) == "Poly(1 + im + (1 - im)x - (1 - im)x^2 - (1 + im)x^3)"
 p = Poly([1.0, 0 + NaN*im, NaN, Inf, 0 - Inf*im]) # handle NaN or Inf appropriately
 @test repr(p) == "Poly(1.0 + NaN*im*x + NaN*x^2 + Inf*x^3 - Inf*im*x^4)"
 
 p = Poly([1,2,3])
-
 @test repr("text/latex", p) == "\$1 + 2\\cdot x + 3\\cdot x^{2}\$"
 p = Poly([1//2, 2//3, 1])
 @test repr("text/latex", p) == "\$\\frac{1}{2} + \\frac{2}{3}\\cdot x + x^{2}\$"
+p = Poly([complex(1,1),complex(0,1),complex(1,0),complex(1,1)])
+@test repr("text/latex", p) == "\$1 + i + i\\cdot x + x^{2} + (1 + i)x^{3}\$"
 
 # customized printing with printpoly
 function printpoly_to_string(args...; kwargs...)