Re: "ocaml_beginners"::[] Re: Conditional compilation

>
>
> Camels,
>
> Thank you everyone for your help. Now I know it should at least be
> possible to achieve what I want. However, I've never used camlp4
> (and I'm running Ocaml 3.10) so I'm afraid that some of your suggestions
> just went over my head. All I want is something as simple as this:
>
> ifdef DEBUG
> then Printf.printf "debug!\n"
> else ()
>
> Surely that camlp4 allows for this with just a few lines, no?
>

>  At toplevel (structure item):
>
>      DEFINE <uident>
>      DEFINE <uident> = <expression>
>      DEFINE <uident> (<parameters>) = <expression>
>      IFDEF <uident> THEN <structure_items> [ ELSE <structure_items> ] (END | ENDIF)
>      IFNDEF <uident> THEN <structure_items> [ ELSE <structure_items> ] (END | ENDIF)
>      INCLUDE <string>
>
>   At toplevel (signature item):
>
>      DEFINE <uident>
>      IFDEF <uident> THEN <signature_items> [ ELSE <signature_items> ] (END | ENDIF)
>      IFNDEF <uident> THEN <signature_items> [ ELSE <signature_items> ] (END | ENDIF)
>      INCLUDE <string>
>
>   In expressions:
>
>      IFDEF <uident> THEN <expression> [ ELSE <expression> ] (END | ENDIF)
>      IFNDEF <uident> THEN <expression> [ ELSE <expression> ] (END | ENDIF)
>      DEFINE <lident> = <expression> IN <expression>
>      __FILE__
>      __LOCATION__
>
>   In patterns:
>
>      IFDEF <uident> THEN <pattern> ELSE <pattern> (END | ENDIF)
>      IFNDEF <uident> THEN <pattern> ELSE <pattern> (END | ENDIF)
>
>   As Camlp4 options:
>
>      -D<uident> or -D<uident>=expr   define <uident> with optional value <expr>
>      -U<uident>                      undefine it
>      -I<dir>                         add <dir> to the search path for INCLUDE'd files
>
>   After having used a DEFINE <uident> followed by "= <expression>", you
>   can use it in expressions *and* in patterns. If the expression defining
>   the macro cannot be used as a pattern, there is an error message if
>   it is used in a pattern.
>
>   You can also define a local macro in an expression usigng the DEFINE ... IN form.
>   Note that local macros have lowercase names and can not take parameters.
>
>   If a macro is defined to = NOTHING, and then used as an argument to a function,
>   this will be equivalent to function taking one less argument. Similarly,
>   passing NOTHING as an argument to a macro is equivalent to "erasing" the
>   corresponding parameter from the macro body.
>
>   The toplevel statement INCLUDE <string> can be used to include a
>   file containing macro definitions and also any other toplevel items.
>   The included files are looked up in directories passed in via the -I
>   option, falling back to the current directory.
>
>   The expression __FILE__ returns the current compiled file name.
>   The expression __LOCATION__ returns the current location of itself.