This syntax file displays unicode characters for some Erlang operators and built-in functions, turning the following:

    A = lists:map(fun (X) -> X end, [1,2,3]),
    B = [1,2,3] =/= A orelse hd(A) >= 5,
    C = not B.

into

    A = lists:map(λ (X) → X end, [1,2,3]),
    B = [1,2,3] ≢ A ∨ hd(A) ≥ 5,
    C = ¬ B.

Screenshot:

This does not – at any point – alter your source code. It simply uses Vim's "conceal" feature to “hide” fun behind λ, etc. Whenever the cursor is at a line with concealed text, the text will be expanded.

To install, simply put erlang.vim in ~/.vim/after/syntax or use something like Pathogen or Vundle (recommended).

Vim ≥ 7.3 is required.

This plug-in is very much inspired by http://github.com/Twinside/vim-haskellConceal.