See the long comment in pervasives.ml for an explanation of the
change. The short summary is that we need to prove more elaborate
properties between the format types involved in the typing of %(...%),
and that proving things by writing GADT functions in OCaml reveals
that Coq's Ltac is a miracle of usability.
Proofs on OCaml GADTs are runtime functions that do have a runtime
semantics: it is legitimate to hope that those proof computations are
as simple as possible, but the current implementation was optimized
for feasability, not simplicity. François Bobot has some interesting
suggestions to simplify the reasoning part (with more equality
reasoning where I used transitivity and symmetry of the
relation profusely), which may make the code simpler in the future
(and possibly more efficient: the hope is that only %(...%) users will
pay a proof-related cost).
git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14897 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
This should make the type-checking of formats simpler and more robust:
instead of trying to find a pair as previously, we can now use the
path of the format6 type directly.
A nice side-effect of the change is that the internal definition of
formats (as a pair) is not printed in error messages anymore.
Because format6 is in fact defined in the CamlinternalFormatBasics
submodule of Pervasives, and has an alias at the toplevel of
Pervasives, error messages still expand the definition:
> Error: This expression has type
> ('a, 'b, 'c, 'd, 'd, 'a) format6 =
> ('a, 'b, 'c, 'd, 'd, 'a) CamlinternalFormatBasics.format6
> but an expression was expected of type ...
Passing the option `-short-paths` does avoid this expansion and
returns exactly the same error message as 4.01:
> Error: This expression has type ('a, 'b, 'c, 'd, 'd, 'a) format6
> but an expression was expected of type ...
(To get this error message without -short-paths, one would need to
define format6 directly in Pervasives; but this type is mutually
recursive with several GADT types that we don't want to add in the
Pervasives namespace unqualified. This is why I'll keep the alias
for now.)
git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14868 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Given that there still remains a small incompatibility (typing of
%(..%)), I decided to keep the legacy mode enabled for now. This means
that any failure related to format can be traced to this
incompatiblity (or unknown regressions), which will simplify the
monitoring and handling of changes considerably. As soon as the %(..%)
typing is generalized, we can turn the legacy mode off (or maybe
simply add warnings for ignored formats).
git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14841 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
(printf {%foo%} bar) will print the string representation of the
format type of both `foo` and `bar`, instead of printing `bar`
(for this purpose one can just use %s). `bar` content is ignored, but
the typer should check that its type is compatible with the one of
`foo`.
This semantics allows to use (printf %{..%}) for testing/debugging the
use of %(...%): put in the brackets what you believe to be the format
type you want to use, and as argument the format you wish to pass, and
you'll get type-checking confidence and the "canonical" representation
of the format string which you can use in the %(...%) -- note that
using the canonical format type is not mandatory.
git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14840 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
This simplifies the charset-handling code, as camlinternalFormat is
allowed to depend on Bytes and String instead of re-importing the
needed primitives.
git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14837 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
The legacy implementation doesn't support "%+_", "%-_" etc. which were
accepted by Benoît's patches. This creates a discrepancy (though not
a regression) that is not necessarily desirable (and in any case makes
fuzz-testing for difference return non-bugs). Long-term, I think that
we're good with the previous, simpler structure where "_" must always
be the first flag.
git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14827 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
When the OCAML_LEGACY_FORMAT environment variable is set, the compiler
will try to emulate the behaviour of the previous implementation of
format.
git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14813 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
To finish the bootstrap cycle, run:
make library-cross
make promote
make partialclean
make core
make library-cross
make promote-cross
make partialclean
make ocamlc ocamllex ocamltools
make library-cross
make promote
make partialclean
make core
make compare
git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14810 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
After applying this patch, you should run:
make library-cross
make promote-cross
make partialclean
make ocamlc ocamllex ocamltools
and then immediately apply the following patches until the "second
part of Benoît Vaugon's format+gadts patch"; the bootstrap cycle is
not finished yet.
git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@14806 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
Damien Doligez
Gabriel Scherer
Leo White
Alain Frisch