The London Perl and Raku Workshop takes place on 26th Oct 2024. If your company depends on Perl, please consider sponsoring and/or attending.
 / 
App-RecordStream-4.0.25
River stage one • 1 direct dependent • 1 total dependent
/ recs-generate

NAME

recs-generate

recs-generate --help-all

Help from: --help-basic:
Usage: recs-generate <args> <command> [<files>]
   Executes <command> for each record to generate a record stream, which is then
   output with a chain link back to the original record.

   <command> is executed opened as a command for each record of input (or
   records from <files>) with $r set to a App::RecordStream::Record object. The
   output lines of each command execution are interpreted as a serialized Recs
   records, one per line. Each such line is reconstituted as a
   App::RecordStream::Record, and the '_chain' key is added to the record before
   it is printed. The value of the '_chain' key is the record that was
   originally passed to the eval expression.

   For instance.  If you did:
   recs-generate "recs-fromatomfeed http://...?key=$r->{title}..."

   with input that looked like:
   { 'title' : 'foo' }
   { 'title' : 'bar' }

   then recs-generate would end up executing:
   recs-fromatomfeed http://...?key=foo...

   and interpreting the result as a series of new line separated records.

   If the result from recs-fromatomfeed was something like:
   { 'title' : 'zip' }
   { 'title' : 'zap' }

   then recs-generate would add the chain link so the output would look like:
   { 'title' : 'zip', 'chain' : { 'title' : 'foo' } }
   { 'title' : 'zap', 'chain' : { 'title' : 'foo' } }

Arguments:
   --e                          a perl snippet to execute, optional
   --E                          the name of a file to read as a perl snippet
   --M module[=...]             execute "use module..." before executing
                                snippet; same behaviour as perl -M
   --m module[=...]             same as -M, but by default import nothing
   --passthrough                Emit input record in addition to generated
                                records
   --keychain <name>            Use 'name' as the chain key (default is
                                '_chain') may be a key spec, see '--help-
                                keyspecs' for more info
   --filename-key|fk <keyspec>  Add a key with the source filename (if no
                                filename is applicable will put NONE)

  Help Options:
      --help-all       Output all help for this script
      --help           This help screen
      --help-keyspecs  Help on keyspecs, a way to index deeply and with regexes

Examples:
   Chain recs from a feed to recs from a second feed and the print the titles.
      recs-fromatomfeed "http://..." | recs-generate "recs-fromatomfeed http://...?key=$r->{title}" | recs-eval 'join("	", $r->{title}, $r->{chain}->{title})'

Help from: --help-keyspecs:
  KEY SPECS
   A key spec is short way of specifying a field with prefixes or regular
   expressions, it may also be nested into hashes and arrays. Use a '/' to nest
   into a hash and a '#NUM' to index into an array (i.e. #2)

   An example is in order, take a record like this:

     {"biz":["a","b","c"],"foo":{"bar 1":1},"zap":"blah1"}
     {"biz":["a","b","c"],"foo":{"bar 1":2},"zap":"blah2"}
     {"biz":["a","b","c"],"foo":{"bar 1":3},"zap":"blah3"}

   In this case a key spec of 'foo/bar 1' would have the values 1,2, and 3 in
   the respective records.

   Similarly, 'biz/#0' would have the value of 'a' for all 3 records

   You can also prefix key specs with '@' to engage the fuzzy matching logic

   Fuzzy matching works like this in order, first key to match wins
     1. Exact match ( eq )
     2. Prefix match ( m/^/ )
     3. Match anywehre in the key (m//)

   So, in the above example '@b/#2', the 'b' portion would expand to 'biz' and 2
   would be the index into the array, so all records would have the value of 'c'

   Simiarly, @f/b would have values 1, 2, and 3

   You can escape / with a \. For example, if you have a record:
   {"foo/bar":2}

   You can address that key with foo\/bar

SEE ALSO