Added kwargs to roots and var kwarg to printpoly

Author: mfalt

src/Polynomials.jl

@@ -612,7 +612,7 @@ julia> roots(poly([1,2,3,4]))
  1.0
 ```
 """
-function roots(p::Poly{T}) where {T}
+function roots(p::Poly{T}; kwargs...) where {T}
     R = promote_type(T, Float64)
     length(p) == 0 && return zeros(R, 0)
 
@@ -634,7 +634,7 @@ function roots(p::Poly{T}) where {T}
     an = p[end-num_trailing_zeros]
     companion[1,:] = -p[(end-num_trailing_zeros-1):-1:num_leading_zeros] / an
 
-    D = eigvals(companion)
+    D = eigvals(companion; kwargs...)
     r = zeros(eltype(D),length(p)-num_trailing_zeros-1)
     r[1:n] = D
     return r

src/show.jl

@@ -90,11 +90,11 @@ julia> printpoly(stdout, Poly([-1, 0, 1], :z), offset=-1, descending_powers=true
 z - z^-1
 ```
 """
-function printpoly(io::IO, p::Poly{T}, mimetype=MIME"text/plain"(); descending_powers=false, offset::Int=0) where {T}
+function printpoly(io::IO, p::Poly{T}, mimetype=MIME"text/plain"(); descending_powers=false, offset::Int=0, var=p.var) where {T}
     first = true
     printed_anything = false
     for i in (descending_powers ? reverse(eachindex(p)) : eachindex(p))
-        printed = showterm(io, p[i], p.var, i+offset, first, mimetype)
+        printed = showterm(io, p[i], var, i+offset, first, mimetype)
         first &= !printed
         printed_anything |= printed
     end

test/runtests.jl

@@ -283,6 +283,12 @@ end
 @test printpoly_to_string(Poly([2, 3, 1], :z), descending_powers=true, offset=-2) == "1 + 3*z^-1 + 2*z^-2"
 @test printpoly_to_string(Poly([-1, 0, 1], :z), offset=-1, descending_powers=true) == "z - z^-1"
 
+# Override symbol in print Issue: #184
+@test printpoly_to_string(Poly([1,2,3], "y"), var=:z) == "1 + 2*z + 3*z^2"
+@test printpoly_to_string(Poly([1,2,3], "y"), descending_powers=true, var="z") == "3*z^2 + 2*z + 1"
+@test printpoly_to_string(Poly([2, 3, 1], :z), descending_powers=true, offset=-2, var=:y) == "1 + 3*y^-1 + 2*y^-2"
+@test printpoly_to_string(Poly([-1, 0, 1], :z), offset=-1, descending_powers=true, var='y') == "y - y^-1"
+
 ## want to be able to copy and paste
 ## check hashing
 p = poly([1,2,3])