Harmatia is a for-fun example of compiler plugins for Ocaml. Harmatia uplifts Ocaml error messages to the world of unicode:

• Digraph are replaced by their unicode equivalent
• Short type names are transliterated to the greek alphabet
• The characters < and > are reserved to relation orders and are replaced by angle brackets ⟨ and ⟩ when they were used as brackets.
• <hv> boxes are replaced with <hov> boxes

Before	After
->	⟶
[|1|]	⟦1⟧
'a	α
...	…
..	‥
< f:'a.'a -> 'a >	⟨f:α.α ⟶ α⟩

How to use harmatia

Unfortunately, compiler plugins currently do no work with toplevel.

Otherwise, first install the harmatia opam package

• clone this repository
• opam pin add harmatia path_to_the_cloned path

Once installed use the -plugin option of either ocamlc or ocamlopt

• ocamlc -plugin $(ocamlfind query harmatia)/harmatia