NAME

  LTSV::LINQ - LINQ-style query interface for LTSV files

SYNOPSIS

  use LTSV::LINQ;

  # From an LTSV log file
  my $results = LTSV::LINQ->FromLTSV('access.log.ltsv')
      ->Where(sub { $_[0]{status} eq '200' })
      ->Select(sub { { path => $_[0]{path}, ua => $_[0]{ua} } })
      ->OrderBy(sub { $_[0]{path} })
      ->ToArray();

  # From an array of hashrefs
  my @data = ({name=>'Alice',score=>85}, {name=>'Bob',score=>70});
  my @top = LTSV::LINQ->From(\@data)
      ->Where(sub { $_[0]{score} >= 80 })
      ->Select(sub { $_[0]{name} })
      ->ToArray();

DESCRIPTION

  LTSV::LINQ brings LINQ-style (Language Integrated Query) chained
  query operations to Perl, with native support for LTSV (Labeled
  Tab-Separated Values) log files.

  Operations are lazy: data is not processed until ToArray(), First(),
  Count(), or another terminal method is called.

INCLUDED DOCUMENTATION

  The eg/ directory contains sample programs:

    eg/01_ltsv_query.pl     Basic LTSV file query with FromLTSV/Where/Select
    eg/02_array_query.pl    LINQ queries on in-memory arrays
    eg/03_grouping.pl       GroupBy, ToLookup, GroupJoin
    eg/04_sorting.pl        OrderBy, ThenBy, multi-key sorting

  The doc/ directory contains LTSV::LINQ cheat sheets in 21 languages
  (English, Japanese, Chinese, Korean, French, and 16 more).
  Each sheet covers: creating queries, filtering, projection,
  sorting, grouping, aggregation, and official spec links.

INSTALLATION

  Manual (no build tools required):

    cp lib/LTSV/LINQ.pm /path/to/your/project/

  Via CPAN:

    cpan LTSV::LINQ
    cpanm LTSV::LINQ

  Via perl Makefile.PL:

    perl Makefile.PL
    make
    make test
    make install

  Via pmake.bat (Windows, no make required):

    pmake.bat test
    pmake.bat install

COMPATIBILITY

  This module works with Perl 5.005_03 and later.

  WHY PERL 5.005_03 SPECIFICATION?

  This module adheres to the Perl 5.005_03 specification--not because we
  use the old interpreter, but because this specification represents the
  simple, original Perl programming model that makes programming enjoyable.

  THE STRENGTH OF MODERN TIMES

  Some people think the strength of modern times is the ability to use
  modern technology. That thinking is insufficient. The strength of modern
  times is the ability to use ALL technology up to the present day.

  By adhering to the Perl 5.005_03 specification, we gain access to the
  entire history of Perl--from 5.005_03 to 5.42 and beyond--rather than
  limiting ourselves to only the latest versions.

  Key reasons:

  - Simplicity: Original Perl approach keeps programming "raku" (easy/fun)
  - JPerl: Final version of JPerl (Japanese Perl)
  - Universal: Runs on ALL Perl versions (5.005_03 through 5.42+)
  - Philosophy: Programming should be enjoyable (Camel Book readers know!)

  Perl 5.6+ introduced character encoding complexity that made programming
  harder. By following the 5.005_03 specification, we maintain the joy of
  Perl programming.

TARGET USE CASES

  - Querying LTSV access logs (Apache, nginx, HTTP::Handy, etc.)
  - Filtering and transforming arrays of hashrefs
  - Data analysis and aggregation without external dependencies
  - Educational use: learning LINQ concepts in Perl

LIMITATIONS

  - All data is processed in memory (no streaming)
  - No SQL support; use DB::Handy for SQL-style queries
  - LTSV parsing is line-oriented; multi-line values are not supported
  - Lazy evaluation defers errors until a terminal method is called

AUTHOR

  INABA Hitoshi <ina@cpan.org>

COPYRIGHT AND LICENSE

  This software is free software; you can redistribute it and/or modify
  it under the same terms as Perl itself.

  See http://www.perl.com/perl/misc/Artistic.html