parsedate: Support formatting presets --iso, --epoch, --pretty

Suggested by Ben Bernard so common use cases don't require looking up
strftime(3) format codes.

Author: tsibley

lib/App/RecordStream/Operation/parsedate.pm

@@ -23,6 +23,9 @@ sub init {
   my $options = {
     'key|k=s'       => sub { $this->{'KEYS'}->add_groups($_[1]) },
     'format|f=s'    => \($this->{'FORMAT'}),
+    'iso|iso8601'   => sub { $this->{'FORMAT'} = '%FT%T%z' },
+    'epoch'         => sub { $this->{'FORMAT'} = '%s' },
+    'pretty'        => sub { $this->{'FORMAT'} = '%c' },
     'dmy'           => \($this->{'UK'}),
     'past'          => \($this->{'PAST'}),
     'future'        => \($this->{'FUTURE'}),
@@ -34,8 +37,11 @@ sub init {
   };
   $this->parse_options($args, $options);
 
-  die "--key is required\n"    unless $this->{'KEYS'}->has_any_group;
-  die "--format is required\n" unless defined $this->{'FORMAT'};
+  die "--key is required\n"
+    unless $this->{'KEYS'}->has_any_group;
+
+  die "--format (or one of --iso, --epoch, or --pretty) is required\n"
+    unless defined $this->{'FORMAT'};
 }
 
 sub accept_record {
@@ -77,6 +83,9 @@ sub usage {
   my $options = [
     ['key|-k <keys>',        'Datetime keys to parse and reformat; may be a key spec or key group.  Required.'],
     ['format|-f <strftime>', 'Format string for strftime(3).  Required.'],
+    ['iso|--iso8601',        'Output datetimes as an ISO 8601 timestamp (equivalent to -f %FT%T%z)'],
+    ['epoch',                'Output datetimes as the number of seconds since the epoch (equivalent to -f %s)'],
+    ['pretty',               'Output datetimes in the locale-preferred format (equivalent to -f %c)'],
     ['dmy',                  'Assume dd/mm (UK-style) instead of mm/dd (US-style)'],
     ['past',                 'Assume ambiguous years and days of the week are in the past'],
     ['future',               'Assume ambiguous years and days of the week are in the future'],

tests/RecordStream/Operation/parsedate.t

@@ -7,13 +7,46 @@ use App::RecordStream::Operation::parsedate;
 
 BEGIN {
   # Normalize localtime for testing
-  $ENV{TZ} = 'US/Pacific';
+  $ENV{TZ}      = 'US/Pacific';
+
+  # This may cause warnings if en_US isn't available on a system running these
+  # tests, but it's the only way to standardize testing for --pretty.
+  $ENV{LC_TIME} = 'en_US';
 }
 
 # These tests aim to exercise the interplay of recs-provided options to
 # parsedate to ensure they're working correctly, not test Time::ParseDate's
 # functionality which is proven elsewhere.
 
+note 'Formatting presets';
+{
+  my @args = qw[ -k when --tz UTC ];
+
+  App::RecordStream::Test::OperationHelper->do_match(
+    'parsedate',
+    [@args, qw[ --iso ]],
+    '{"when":"2016-02-28 18:45:18"}',
+    '{"when":"2016-02-28T10:45:18-0800"}',
+    "--iso: 2016-02-28 18:45:18 is 2016-02-28T10:45:18-0800",
+  );
+
+  App::RecordStream::Test::OperationHelper->do_match(
+    'parsedate',
+    [@args, qw[ --epoch ]],
+    '{"when":"2016-02-28 18:45:18"}',
+    '{"when":"1456685118"}',
+    "--epoch 2016-02-28 18:45:18 is 1456685118",
+  );
+
+  App::RecordStream::Test::OperationHelper->do_match(
+    'parsedate',
+    [@args, qw[ --pretty ]],
+    '{"when":"2016-02-28 18:45:18"}',
+    '{"when":"Sun 28 Feb 2016 10:45:18 AM PST"}',
+    "--pretty 2016-02-28 18:45:18 is Sun 28 Feb 2016 10:45:18 AM PST",
+  );
+}
+
 note 'Timezones';
 {
   my @args = qw[ -k when --format %T ];