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             mr_agg(<<[1, {{ct}}]>>, <<[$a->[0] + $b->[0], $a->[1] + $b->[1]]>>, <<$a->[1] / $a->[0]>>)
 
    rec()
    record()
       A valuation that just returns the entire record.
 
    snip(snip)
       Takes a snippet and returns both the snippet and the snippet as a
       valuation. Used to distinguished snippets from scalars in cases where it
       matters, e.g. min('{{x}}') interprets it is a keyspec when it was meant to
       be a snippet (and then a valuation), min(snip('{{x}}')) does what is
       intended. This is used internally by <<...>> and in fact <<...>> just
       translates to snip('...').
 
    subset_agg(<snippet>, <aggregator>)
    subset_aggregator(<snippet>, <aggregator>)
       Takes a snippate to act as a record predicate and an aggregator and
       produces an aggregator that acts as the provided aggregator as run on the
       filtered view.
 
       Example(s):
           An aggregator that counts the number of records with a time not above 6 seconds:
              subset_agg(<<{{time_ms}} <= 6000>>, ct())
 
    type_agg(obj)
    type_scalar(obj)
    type_val(obj)
       Force the object into a specific type. Can be used to force certain
       upconversions (or avoid them).
 
    valuation(sub { ... })
    val(sub { ... })
       Takes a subref, creates a valuation that represents it. The subref will
       get the record as its first and only argument.
 
       Example(s):
          To get the square of the "x" field:
             val(sub{ $[0]->{x} ** 2 })
 
    xform(<aggregator>, <snippet>)
       Takes an aggregator and a snippet and produces an aggregator the
       represents invoking the snippet on the aggregator's result.
 
       Example(s):
          To take the difference between the first and second time fields of the record collection:
             xform(recs(), <<{{1/time}} - {{0/time}}>>)
 
 Help from: --help-keygroups:
 KEY GROUPS
    SYNTAX: !regex!opt1!opt2... Key groups are a way of specifying multiple
    fields to a recs command with a single argument or function. They are
    generally regexes, and have several options to control what fields they
    match. By default you give a regex, and it will be matched against all first
    level keys of a record to come up with the record list. For instance, in a
    record like this:
 
    { 'zip': 1, 'zap': 2, 'foo': { 'bar': 3 } }
 
    Key group: !z! would get the keys 'zip' and 'zap'
 
    You can have a literal '!' in your regex, just escape it with a \.
 
    Normally, key groups will only match keys whose values are scalars. This can
    be changed with the 'returnrefs' or rr flag.
 
    With the above record !f! would match no fields, but !f!rr would match foo
    (which has a value of a hash ref)
 
    Options on KeyGroups:
       returnrefs, rr  - Return keys that have reference values (default:off)
       full, f         - Regex should match against full keys (recurse fully)
       depth=NUM,d=NUM - Only match keys at NUM depth (regex will match against
                         full keyspec)
       sort, s         - sort keyspecs lexically
 
 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
 
 Help from: --help-more:
 Usage: recs-multiplex <args> -- <other recs operation>
    Take records, grouped together by --keys, and run an operation for
    each group.
 
 Arguments:
    --key|-k <keys>              Comma separated list of key fields. May be a key
                                 spec or key group
    --dlkey|-K ...               Specify a domain language key. See "Domain
                                 Language Integration" section in --help-more.
    --size|--sz|-n <number>      Number of running clumps to keep.
    --adjacent|-1                Only group together adjacent records. Avoids
                                 spooling records into memeory
    --cube                       See "Cubing" section in --help-more.
    --clumper ...                Use this clumper to group records. May be
                                 specified multiple times. See --help-clumping.
    --dlclumper ...              Use this domain language clumper to group
                                 records. May be specified multiple times. See
                                 --help-clumping.
    --line-key|-L <key>          Use the value of this key as line input for the
                                 nested operation (rather than the entire
                                 record). Use with recs-from* scripts generally.
    --list-clumpers              Bail and output a list of clumpers
    --show-clumper <clumper>     Bail and output this clumper's detailed usage.
    --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-clumping        Help on clumping; mechanisms to group records
                              across a stream
       --help-domainlanguage  Help on the recs domain language, a [very
                              complicated] way of specifying valuations (which
                              act like keys) or aggregators
       --help-keygroups       Help on keygroups, a way of specifying
                              multiple keys
       --help-keys            Help on keygroups and keyspecs
       --help-keyspecs        Help on keyspecs, a way to index deeply and
                              with regexes
       --help-more            Larger help documentation
 
 Examples:
    Separate out a stream of text by PID into separate invocations of recs-frommultire.
       recs-fromre '^(.*PID=([0-9]*).*)$' -f line,pid | recs-multiplex -L line -k pid -- recs-frommultire ...
   Tag lines with counts by thread
       recs-multiplex -k thread -- recs-eval '{{nbr}} = ++$nbr'
 
 Cubing:
    Instead of added one entry for each input record, we add 2 ** (number of key
    fields), with every possible combination of fields replaced with the default
    of "ALL". This is not meant to be used with --adjacent or --size. If our key
    fields were x and y then we'd get output for {x = 1, y = 2}, {x = 1, y =
    ALL}, {x = ALL, y = 2} and {x = ALL, y = ALL}.
 
 Domain Lanuage Integration: