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package App::CSVUtils::csv_grep;

use 5.010001;
use strict;
use warnings;

our $AUTHORITY = 'cpan:PERLANCAR'; # AUTHORITY
our $DATE = '2025-02-04'; # DATE
our $DIST = 'App-CSVUtils'; # DIST
our $VERSION = '1.036'; # VERSION

use App::CSVUtils qw(
                        gen_csv_util
                        compile_eval_code
                        eval_code
                );

gen_csv_util(
    name => 'csv_grep',
    summary => 'Select (only output) row(s) where Perl expression returns true',
    description => <<'_',

This is like Perl's `grep` performed over rows of CSV. In `$_`, your Perl code
will find the CSV row as an arrayref (or, if you specify `-H`, as a hashref).
`$main::row` is also set to the row (always as arrayref). `$main::rownum`
contains the row number (2 means the first data row). `$main::csv` is the
<pm:Text::CSV_XS> object. `$main::fields_idx` is also available for additional
information.

Your code is then free to return true or false based on some criteria. Only rows
where Perl expression returns true will be included in the result.

_
    add_args => {
        %App::CSVUtils::argspecopt_hash,
        %App::CSVUtils::argspec_eval,
    },
    tags => ['category:filtering', 'accepts-code'],

    examples => [
        {
            summary => 'Only show rows where the amount field '.
                'is divisible by 7',
            argv => ['-He', '$_->{amount} % 7 == 0', 'file.csv'],
            test => 0,
            'x.doc.show_result' => 0,
        },
        {
            summary => 'Only show rows where date is a Wednesday',
            argv => ['-He', 'BEGIN { use DateTime::Format::Natural; $parser = DateTime::Format::Natural->new } $dt = $parser->parse_datetime($_->{date}); $dt->day_of_week == 3', 'file.csv'],
            test => 0,
            'x.doc.show_result' => 0,
        },
    ],
    links => [
        {url=>'prog:csvgrep'},
    ],

    on_input_header_row => sub {
        my $r = shift;

        # we add the following keys to the stash
        $r->{code} = compile_eval_code($r->{util_args}{eval}, 'eval');

        $r->{wants_input_row_as_hashref} = 1 if $r->{util_args}{hash};
    },

    on_input_data_row => sub {
        my $r = shift;

        $r->{code_print_row}->($r->{input_row})
            if eval_code($r->{code}, $r, $r->{wants_input_row_as_hashref} ? $r->{input_row_as_hashref} : $r->{input_row});
    },
);

1;
# ABSTRACT: Select (only output) row(s) where Perl expression returns true

__END__

=pod

=encoding UTF-8

=head1 NAME

App::CSVUtils::csv_grep - Select (only output) row(s) where Perl expression returns true

=head1 VERSION

This document describes version 1.036 of App::CSVUtils::csv_grep (from Perl distribution App-CSVUtils), released on 2025-02-04.

=head1 FUNCTIONS


=head2 csv_grep

Usage:

 csv_grep(%args) -> [$status_code, $reason, $payload, \%result_meta]

Select (only output) row(s) where Perl expression returns true.

Examples:

=over

=item * Only show rows where the amount field is divisible by 7:

 csv_grep(
     input_filename => "file.csv",
   eval => "\$_->{amount} % 7 == 0",
   hash => 1
 );

=item * Only show rows where date is a Wednesday:

 csv_grep(
     input_filename => "file.csv",
   eval => "BEGIN { use DateTime::Format::Natural; \$parser = DateTime::Format::Natural->new } \$dt = \$parser->parse_datetime(\$_->{date}); \$dt->day_of_week == 3",
   hash => 1
 );

=back

This is like Perl's C<grep> performed over rows of CSV. In C<$_>, your Perl code
will find the CSV row as an arrayref (or, if you specify C<-H>, as a hashref).
C<$main::row> is also set to the row (always as arrayref). C<$main::rownum>
contains the row number (2 means the first data row). C<$main::csv> is the
L<Text::CSV_XS> object. C<$main::fields_idx> is also available for additional
information.

Your code is then free to return true or false based on some criteria. Only rows
where Perl expression returns true will be included in the result.

This function is not exported.

Arguments ('*' denotes required arguments):

=over 4

=item * B<eval>* => I<str|code>

Perl code.

=item * B<hash> => I<bool>

Provide row in $_ as hashref instead of arrayref.

=item * B<inplace> => I<true>

Output to the same file as input.

Normally, you output to a different file than input. If you try to output to the
same file (C<-o INPUT.csv -O>) you will clobber the input file; thus the utility
prevents you from doing it. However, with this C<--inplace> option, you can
output to the same file. Like perl's C<-i> option, this will first output to a
temporary file in the same directory as the input file then rename to the final
file at the end. You cannot specify output file (C<-o>) when using this option,
but you can specify backup extension with C<-b> option.

Some caveats:

=over

=item * if input file is a symbolic link, it will be replaced with a regular file;

=item * renaming (implemented using C<rename()>) can fail if input filename is too long;

=item * value specified in C<-b> is currently not checked for acceptable characters;

=item * things can also fail if permissions are restrictive;

=back

=item * B<inplace_backup_ext> => I<str> (default: "")

Extension to add for backup of input file.

In inplace mode (C<--inplace>), if this option is set to a non-empty string, will