meta()

The filter rule module must contain "meta" subroutine which must return a hashref (DefHash) that has the following keys ("*" marks that the key is required):

• v* => int (default: 1)

  Metadata specification version. From DefHash. Currently at 1.

• summary => str

  From DefHash.

• might_fail => bool

  Whether coercion might fail, e.g. because of invalid input. If set to 1, "expr_filter" key that the filter() routine returns must be an expression that returns an array (envelope) of "(error_msg, data)" instead of just filtered data. Error message should be a string that is set when filtering fails and explains why. Otherwise, if filtering succeeds, the error message string should be set to undefined value.

  This is used for filtering rules that act as a data checker.

• args => hash

  List of arguments that this filter accepts, in the form of hash where hash keys are argument names and hash values are argument specifications. Argument specification is a DefHash similar to argument specification for functions in Rinci::function specification.

filter()

The filter rule module must also contain "filter" subroutine which must generate the code for filtering. The subroutine must accept a hash of arguments and will be passed these:

• data_term => str
• args => hash

  The arguments for the filter. Hash keys will contain the argument names, while hash values will contain the argument's values.

The "filter" subroutine must return a hashref with the following keys ("*" indicates required keys):

• expr_filter* => str

  Expression in the target language to actually convert data.

• modules => hash

  A list of modules required by the expression, where hash keys are module names and hash values are modules' minimum versions.

Basically, the "filter" subroutine must generate a code that accepts a non-undef data and must convert this data to the desired value.

Program/library that uses Data::Sah::Filter can collect rules from the rule modules then compose them into the final code, something like (in pseudo-Perl code):

 if (!defined $data) {
   return undef;
 } else {
   $data = expr-filter-from-rule1($data);
   $data = expr-filter-from-rule2($data);
   ...
   return $data;
 }

Filter modules included in this distribution

1. Data::Sah::Filter::js::Str::downcase

2. Data::Sah::Filter::js::Str::lc

3. Data::Sah::Filter::js::Str::lcfirst

4. Data::Sah::Filter::js::Str::lowercase

5. Data::Sah::Filter::js::Str::ltrim

6. Data::Sah::Filter::js::Str::rtrim

7. Data::Sah::Filter::js::Str::trim

8. Data::Sah::Filter::js::Str::uc

9. Data::Sah::Filter::js::Str::ucfirst

10. Data::Sah::Filter::js::Str::upcase

11. Data::Sah::Filter::js::Str::uppercase

12. Data::Sah::Filter::perl::Array::check_uniq

13. Data::Sah::Filter::perl::Array::check_uniqnum

14. Data::Sah::Filter::perl::Array::check_uniqstr

15. Data::Sah::Filter::perl::Array::remove_undef

16. Data::Sah::Filter::perl::Array::uniq

17. Data::Sah::Filter::perl::Array::uniqnum

18. Data::Sah::Filter::perl::Array::uniqstr

19. Data::Sah::Filter::perl::Float::ceil

20. Data::Sah::Filter::perl::Float::check_has_fraction

21. Data::Sah::Filter::perl::Float::check_int

22. Data::Sah::Filter::perl::Float::floor

23. Data::Sah::Filter::perl::Float::round

24. Data::Sah::Filter::perl::Str::check

25. Data::Sah::Filter::perl::Str::check_lowercase

26. Data::Sah::Filter::perl::Str::check_oneline

27. Data::Sah::Filter::perl::Str::check_uppercase

28. Data::Sah::Filter::perl::Str::downcase

29. Data::Sah::Filter::perl::Str::ensure_trailing_newline

30. Data::Sah::Filter::perl::Str::lc

31. Data::Sah::Filter::perl::Str::lcfirst

32. Data::Sah::Filter::perl::Str::lowercase

33. Data::Sah::Filter::perl::Str::ltrim

34. Data::Sah::Filter::perl::Str::oneline

35. Data::Sah::Filter::perl::Str::remove_comment

36. Data::Sah::Filter::perl::Str::remove_non_latin_alphanum

37. Data::Sah::Filter::perl::Str::remove_nondigit

38. Data::Sah::Filter::perl::Str::remove_whitespace

39. Data::Sah::Filter::perl::Str::replace_map

40. Data::Sah::Filter::perl::Str::rtrim

41. Data::Sah::Filter::perl::Str::trim

42. Data::Sah::Filter::perl::Str::try_center

43. Data::Sah::Filter::perl::Str::uc

44. Data::Sah::Filter::perl::Str::ucfirst

45. Data::Sah::Filter::perl::Str::underscore_non_latin_alphanum

46. Data::Sah::Filter::perl::Str::underscore_non_latin_alphanums

47. Data::Sah::Filter::perl::Str::upcase

48. Data::Sah::Filter::perl::Str::uppercase

49. Data::Sah::Filter::perl::Str::wrap

$Log_Filter_Code => bool (default: from ENV or 0)

If set to true, will log the generated filter code (currently using Log::ger at trace level). To see the log message, e.g. to the screen, you can use something like:

 % TRACE=1 perl -MLog::ger::LevelFromEnv -MLog::ger::Output=Screen \
     -MData::Sah::Filter=gen_filter -E'my $c = gen_filter(...)'

gen_filter

Usage:

 gen_filter(%args) -> any

Generate filter code.

This is mostly for testing. Normally the filter rules will be used from Data::Sah.

This function is not exported by default, but exportable.

Arguments ('*' denotes required arguments):

• filter_names* => array[str]

  (No description)

• return_type => str (default: "val")

  (No description)

Return value: (any)

LOG_SAH_FILTER_CODE => bool

Set default for $Log_Filter_Code.