A double call to pp_module_type inside Ocaml.pp_specif was
causing an complexity blowup when pretty-printing heavily modular
extracted code.
I wasn't able to figure out why this double call is there. It could
be the leftover of some intermediate work in 2007 before commit 350398eae
(which introduced global printing phases Pre/Impl/Intf).
Anyway I'm reasonably sure that today these two pp_module_type calls produce
the exact same pretty-printed signature (even if there's a large bunch of
imperative states around). Moreover, this duplicated signature is actually
slightly wrong: when we alias a module M with a unambiguous name like Coq__123,
the type of Coq__123 should not be an exact copy of the type of M, but rather
a "strengthened" version of it (with equality between inductive types).
So the best solution is now to use this funny feature of OCaml introduced in 3.12 :
module Coq__123 : module type of struct include M end
This "module type of struct include" is slightly awkward, but short, correct,
and trivial to produce :-). And I doubt anybody will object to the (rare) use
of some 3.12 features in extracted code of 2017...
baa60ff...
by
Nickolai Zeldovich <email address hidden>
Fix Haskell extraction for terms over 45 characters long
The Haskell extraction code would allow line-wrapping of the Haskell
type definition, which would lead to unparseable Haskell code when the
linebreak occured just before the type name. In particular, with a term
name of 46 characters or more, the following Coq code:
Definition xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx := tt.
Extraction Language Haskell.
Extraction xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx.
would produce:
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ::
Unit
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx =
Tt
which failed to compile with GHC (according to Haskell's indentation
rules, the "Unit" line must be indented to be treated as a continuation
of the previous line).
This patch always forces the type onto a separate line, and ensures that
it is always indented by 2 spaces (just like the body of each definition).
