Discrete mathematics (also finite mathematics) deals with topics such as logic, set theory, information theory, partially ordered sets, proofs, relations, and a number of other topics.
For other branches of mathematics, there are tools that support programming. For statistics, there is R and S that have many useful statistics functions built in. For numerical analysis, Octave can be used as a language or integrated into C++.
I don't know of any languages or packages that deal specifically with discrete mathematics (although just about every language can be used to implement algorithms used in discrete mathematics, there should be libraries or environments out there designed specifically for these applications).