Re: [PATCH v2] pkl: Add exception_code to register user-defined exceptions

[Jose E. Marchesi]

Hi Mohammad.

> 2021-01-25  Mohammad-Reza Nabipoor  <m.nabipoor@yahoo.com>
>
>       * libpoke/pkl-rt.pk (exception_code): New function.
>       * doc/poke.texi (Exceptions): Add documentation for
>       `exception_code`.

OK for master.
Thanks!

> ---
>  ChangeLog         |  5 +++++
>  doc/poke.texi     | 14 ++++++++++++++
>  libpoke/pkl-rt.pk | 13 ++++++++++++-
>  3 files changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/ChangeLog b/ChangeLog
> index a92820ce..900a41d3 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,8 @@
> +2021-01-25  Mohammad-Reza Nabipoor  <m.nabipoor@yahoo.com>
> +
> +     * libpoke/pkl-rt.pk (exception_code): New function.
> +     * doc/poke.texi (Exceptions): Add documentation for `exception_code`.
> +
>  2021-01-25  Mohammad-Reza Nabipoor  <m.nabipoor@yahoo.com>
>  
>       * testsuite/Makefile.am (check-DEJAGNU): Fix `make distcheck`
> diff --git a/doc/poke.texi b/doc/poke.texi
> index 8aeb07cb..ad36fa2f 100644
> --- a/doc/poke.texi
> +++ b/doc/poke.texi
> @@ -10190,6 +10190,20 @@ example:
>  raise Exception @{ code = 255; msg = "double upset event" @};
>  @end example
>  
> +User-defined exceptions should be resgistered using @code{exception_code}
> +function.  For example:
> +
> +@example
> +var E_my_exception = Exception @{
> +  code = exception_code,
> +  msg = "double upset event",
> +@};
> +@end example
> +
> +@noindent
> +where the @code{E_my_exception.code} is a unique number greater than or
> +equal to @code{255}.
> +
>  Exception codes in the range @code{0..254} are reserved for poke.
>  These are used in predefined exceptions which are standard, and have
>  specific meanings:
> diff --git a/libpoke/pkl-rt.pk b/libpoke/pkl-rt.pk
> index 9947d4d3..658ecd37 100644
> --- a/libpoke/pkl-rt.pk
> +++ b/libpoke/pkl-rt.pk
> @@ -77,7 +77,8 @@ type Exception =
>  /* Standard exception codes.
>     These codes should be in sync with PVM_E_* macros in pvm.h.
>     Note that user-defined exceptions must have codes starting with
> -   255.
> +   255 (and should be registered using exception_code function defined
> +   below).
>     Note also that EC_generic _must_ be zero.  */
>  
>  var EC_generic       = 0;
> @@ -135,6 +136,16 @@ var E_exit
>  var E_assert
>    = Exception {code = EC_assert, msg = "assertion failure", exit_status = 1};
>  
> +/* Registration of user-defined exceptions */
> +
> +type _ExceptionCodeGenerator = () int<32>;
> +var exception_code = lambda _ExceptionCodeGenerator:
> +  {
> +    var n = 255; /* First available code for user-defined exceptions */
> +
> +    return lambda int<32>: { return n++; };
> +  }();
> +
>  /* Default exception handler.
>  
>     Note that the code in this function should NOT raise any exception,