Another possibility: introduce a special "extends" syntax to Julia, e.g.
module Hecke
type SpecialMat <: Nemo.MatElem
end
function det(a::SpecialMat)
if blah
# do whatever
else
Nemo.det
end
end
extends det Nemo.det # tells Julia to somehow treat the det implementation
above specially so it can call the Nemo version of the function without
calling itself.
end # module
The behaviour would be: if extends is missing, it gives an ambiguity
warning about Nemo.det vs Hecke.det if someone calls det after including
Hecke and Nemo.
Bill.
