dmitri has asked for the wisdom of the Perl Monks concerning the following question:

Does anyone use format anymore? And if so, for what? I was just reading perl591delta and I see that the formats are undergoing changes -- so someone must be using them somewhere.

Grepping my local /usr/lib/perl produces matches in Pod::Functions and Parse::RecDescent (this one uses it for error formatting). Anything else you know of?

In my close to a decade of Perl programming, I've never had an opportunity to use format for anything. Am I missing out?

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Re: Useful usage of formats.
by graff (Chancellor) on Apr 11, 2007 at 04:08 UTC
    In my close to a decade of Perl programming, I've never had an opportunity to use format for anything. Am I missing out?

    Maybe not. ;-) I'm with you. In my 12 years of perl programming, I've never needed anything that goes beyond the scope of that old friend from my preceding 10 years with C: (s)printf.

    Maybe some of my code would be considered by some as "too complicated" or even "suboptimal" as a result, but it's really just a matter of what you happen to be comfortable with.

    (And Perl is that rarety among programming languages, where the choice of solution can be a matter of one's own comfort level, rather than being dictated by syntactic constraints or a limited library of available support functions.)

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Re: Useful usage of formats.
by gloryhack (Deacon) on Apr 11, 2007 at 04:15 UTC
    I use format frequently, for creating nicely formatted outputs from reporting functions. Management types love their reports, after all, so there are a bazillion excuses to use formats. Formats are great for presenting columnar data.

    The application I'm working on now, in fact, is going to see format tomorrow when I plug in its reporting function. I was all set to use a template engine, but I'd feel bad if I didn't leave something interesting for the maintenance programmer to play with. Besides, it gets me out of truncating overlong strings before handing them off to a template engine.

    Yeah, you might be missing out.

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Re: Useful usage of formats.
by polettix (Vicar) on Apr 11, 2007 at 09:49 UTC
    IIRC, formats will be tossed away from Perl 6, and their functionality will be provided by a module. TheDamian anticipated this functionality in a module you can use today from within Perl 5, namely Perl6::Form, that should be suitable for production-level scripts and modules according to Categorized Damian Modules. IMHO, this means that you can ignore formats today and stick to the module.

    Flavio
    perl -ple'$_=reverse' <<<ti.xittelop@oivalf

    Don't fool yourself.
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Re: Useful usage of formats.
by shmem (Chancellor) on Apr 11, 2007 at 09:34 UTC
    I use format quite often to generate sort-of manual pages for interfaces, e.g. while programming perl frontends to SAP. Sample output of that particular usage: 
    ======================================================================
+==========
Interface RFC_READ_TABLE
======================================================================
+==========
+----------------------------------------------------------+----------
+---------+
| TABLE  | DATA                            | LEN        512| INTYPE   
+        4|
| STRUCT | TAB512                                          | VALUE LEN
+       0 |
+--------+---------------------------------+------+--------+--------+-
+---------+
| POS    | NAME                            | LEN  | INTYPE | OFFSET | 
+DECIMALS |
+--------+---------------------------------+------+--------+--------+-
+---------+
|      1 | WA                              |  512 |      0 |        | 
+       0 |
|    --- | - Summe -                       |  512 |        |        | 
+         |


+----------------------------------------------------------+----------
+---------+
| TABLE  | FIELDS                          | LEN        103| INTYPE   
+        4|
| STRUCT | RFC_DB_FLD                                      | VALUE LEN
+       0 |
+--------+---------------------------------+------+--------+--------+-
+---------+
| POS    | NAME                            | LEN  | INTYPE | OFFSET | 
+DECIMALS |
+--------+---------------------------------+------+--------+--------+-
+---------+
|      1 | FIELDNAME                       |   30 |      0 |        | 
+       0 |
|      2 | OFFSET                          |    6 |      6 |     30 | 
+       0 |
|      3 | LENGTH                          |    6 |      6 |     36 | 
+       0 |
|      4 | TYPE                            |    1 |      0 |     42 | 
+       0 |
|      5 | FIELDTEXT                       |   60 |      0 |     43 | 
+       0 |
|    --- | - Summe -                       |  103 |        |        | 
+         |

...

======================================================================
+==========
 Parameter
======================================================================
+==========
|------------------------------------+--------------------------------
+---------+
| PARAMETER DELIMITER                | STRUCTURE (none)               
+         |
| VALUE                     | LEN    | TYPE | INTYPE | DECIMALS | DEFA
+ULT      |
|                           |      1 |   IN |        |        0 |     
+        0|


|------------------------------------+--------------------------------
+---------+
| PARAMETER NO_DATA                  | STRUCTURE (none)               
+         |
| VALUE                     | LEN    | TYPE | INTYPE | DECIMALS | DEFA
+ULT      |
|                           |      1 |   IN |        |        0 |     
+        0|

    [download]

    There's some ANSI color highlighting that I can't show in a <code> block. This lets me skim through an interface definition while developing whithout having to use the ugly SAP Frontend...

    Anyways, doing something like this with printf would be a pain. Same goes for all 'er' of Perl - 'Extraction and Report'. I use format for log file parsing output, mail body assembling, en fin for all stuff I'm loth to use a templating engine for.

    --shmem 

    _($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}
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Re: Useful usage of formats.
by Anonymous Monk on Apr 11, 2007 at 03:56 UTC
    Damian uses format, so you must be missing out :)
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      That's true :) But my error messages are just not as intricate as his...
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