Started work on an undefined literal removal pass for the ocaml

backed.

Ocaml doesn't support undefined values, so we need a way to remove
them from the specification in order to generate good ocaml
code. There are more subtle issues to - like if we initialize a
mutable variable with an undefined list, then the ocaml runtime has no
way of telling what it's length should be (as this information is
removed by the simple_types pass).

We therefore rewrite undefined literals with calls to functions that
create undefined types, e.g.

(bool) undefined becomes undefined_bool ()

(vector<'n,'m,dec,bit>) undefined becomes undefined_vector(sizeof 'n, sizeof 'm, undefined_bit ())

We therefore have to generate undefined_X functions for any user
defined datatype X. initial_check seems to be the logical place for
this. This is straightforward provided the user defined types are
not-recursive (and it shouldn't be too bad even if they are).

1 files changed, 2 insertions, 1 deletions

diff --git a/src/parser2.mly b/src/parser2.mly
index bde542e0..42e13721 100644
--- a/src/parser2.mly
+++ b/src/parser2.mly
@@ -153,6 +153,8 @@ let rec desugar_rchain chain s e =
 %token <string> Op0r Op1r Op2r Op3r Op4r Op5r Op6r Op7r Op8r Op9r
 
 %start file
+%start typschm
+%type <Parse_ast.typschm> typschm
 %type <Parse_ast.defs> defs
 %type <Parse_ast.defs> file
 
@@ -1022,4 +1024,3 @@ defs:
 file:
   | defs Eof
     { $1 }
-