Re: [PATCH 0/2] Add more context to E_constraint msg

[Jose E. Marchesi]

Hi Mohammad.

> Hi Jose.
>
> This series enrich the msg field of E_constraint to give the user
> more information of the definition location and evaluation location.
>
> Example:
>
> ```
> (poke) type A =  struct { int i == 1; }
> (poke) var a = A{}
> (poke) a.i++
> unhandled constraint violation exception
> failed expression
>   i == 1
> in field A.i evaluated at <stdin>:1:1 (defined at <stdin>:1:24)
> ```
>
> I think, it's much more readable than
>
> ```
> unhandled constraint violation exception
> failed expression
>   i == 1
> in field A.i
> ```
>
> Imagine when you're loading a pickle that's loading another one,
> and somewhere there, a constraint violation is happening.
>
> One thing that is, IMHO, even better, is to add a `detailed_info` field
> to the exception, and report the whole stack of locations from the
> first expr/stmt to the core expr that is the main point of failure.
>
> Currently, I've introduced a `locationstack' to keep track of the
> location info, and only reporting the location from top of that stack.

This is very nice.  I like the approach.

I also agree that would be good to have a detailed_info field with a
textual representation of the stack, like:

  in field A.i
  evaluated at LOC (defined at LOC)
            at LOC (defined at LOC)
            ...

I think it would be good to have the "evaluated ..." in its own line,
separated from the "in field FIELD" line.

A Poke function could be written:

  fun _pkl_print_location_stack (uint<32> indent_level = 0,
                                 uint<32> depth = 0) void:

That could print:

at LOC (defined at LOC)NEWLINE
INDENT_LEVEL_SPACEsat LOC (defined at LOC)NEWLINE

Or something like that.
Also, I think this needs more tests 8-)

>
>
> Regards,
> Mohammad-Reza
>
>
> Mohammad-Reza Nabipoor (2):
>   pkl: report location of constraint definition
>   pkl: report evaluation location in E_constraint exception
>
>  ChangeLog                           |  54 +++++++++++++
>  libpoke/pkl-ast.c                   |   6 ++
>  libpoke/pkl-ast.h                   |   7 ++
>  libpoke/pkl-gen.c                   |  77 +++++++++++++++++++
>  libpoke/pkl-gen.pks                 |   4 +
>  libpoke/pkl-insn.def                |   5 ++
>  libpoke/pkl-rt.pk                   |  16 ++--
>  libpoke/pkl-tab.y                   |  22 +++++-
>  libpoke/pvm.jitter                  | 113 ++++++++++++++++++++++++++++
>  testsuite/poke.pickles/pcap-test.pk |   3 +-
>  10 files changed, 299 insertions(+), 8 deletions(-)