=head1 NAME

recs-collate

=head1 recs-collate --help-all

 Help from: --help-aggregators:
 average, avg: averages provided field
 cb, countby: counts by unique value for a field
 concat, concatenate: concatenate values from provided field
 corr, correl, correlation: find correlation of provided fields
 count, ct: counts (non-unique) records
 cov, covar, covariance: find covariance of provided fields
 dcount, dct, distinctcount, distinctct: count unique values from provided field
 first: first value for a field
 firstrec, firstrecord: first record
 last: last value for a field
 lastrec, lastrecord: last record seen
 linearregression, linreg: perform a linear regression of provided fields, dumping various statistics
 max, maximum: maximum value for a field
 min, minimum: minimum value for a field
 mode: most common value for a field
 perc, percentile: value of pXX for field
 percentilemap, percmap: map of percentile values for field
 recformax, recformaximum, recordformax, recordformaximum: returns the record corresponding to the maximum value for a field
 recformin, recforminimum, recordformin, recordforminimum: returns the record corresponding to the minimum value for a field
 records, recs: returns an arrayref of all records
 stddev: find standard deviation of provided field
 sum: sums provided field
 uconcat, uconcatenate: concatenate unique values from provided field
 valuestokeys, vk: use one key-value as a key for a different value in the record
 var, variance: find variance of provided field
 
 Help from: --help-basic:
 Usage: recs-collate <args> [<files>]
    Take records, grouped togther by --keys, and compute statistics (like average, count, sum, concat, etc) within those groups.
 
    For starting with collate, try doing single --key collates with some number of aggregators (list available in --list-agrregators)
 
 Arguments:
    --key|-k <keys>                 Comma separated list of key fields. May be a key spec or key group
    --dlkey ...                     Specify a domain language key. See "Domain Language Integration" below.
    --dlaggregator ...              Specify a domain language aggregate. See "Domain Language Integration" below.
    --aggregator|-a <aggregators>   Colon separated list of aggregate field specifiers. See "Aggregates" section below.
    --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 below.
    --cube-default                  See "Cubing" section below.
    --incremental                   Output a record every time an input record is added to a clump (instead of everytime a clump is flushed).
    --list-aggregators              Bail and output a list of aggregators
    --show-aggregator <aggregator>  Bail and output this aggregator's detailed usage.
    --ignore-null                   Ignore undefined or non-existant keys in records
    --filename-key|fk <keyspec>     Add a key with the source filename (if no filename is applicable will put NONE)
 
   Help Options:
       --help-aggregators     List the aggregators
       --help-all             Output all help for this script
       --help                 This help screen
       --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:
    Count clumps of adjacent lines with matching x fields.
       recs-collate --adjacent --key x --aggregator count
    Count number of each x field value in the entire file.
       recs-collate --key x --aggregator count
    Finds the maximum latency for each date, hour pair
       recs-collate --key date,hour --aggregator worst_latency=max,latency
    Find the median value of x+y in records
       recs-collate --dlaggregator "m=perc(50,snip(<<{{x}}+{{y}}>>))"
 
 Help from: --help-domainlanguage:
 DOMAIN LANGUAGE
    The normal mechanism for specifying keys and aggregators allows one to concisely instantiate the objects that back them in the platform and is certainly the easiest way to use recs. The record stream domain language allows the
    creation of these objects in a programmatic way, with neither the syntactic issues of the normal way nor its guiding hand.
 
    The domain language is itself just PERL with a collection of library functions for creating platform objects included. Your favorite aggregators are all here with constructors matching their normal token. For convenience of e.g.
    last, aggregators are also included with a prefixed underscore.
 
    Below you can find documentation on all the "built in" functions. Most aggregators and deaggregators should be present with arguments comparable to their normal instantiation arugments, but with keyspec parameters replaced with
    valuations parameters.
 
 Special Syntax
    Where one sees a <snippet> argument below, a string scalar is expected, however quoting these can get fairly difficult and they can be confused with non-<snippet> scalars.
 
    Example:
      --dla "ucancat(',', snip('{{x}} * 2'))"
 
    To remedy this, one may use <<code>> to inline a snippet which will be immediately understood by the typing mechanism as being code. Escaping inside this is as single quotes in PERL.
 
    Example With <<CODE>>
      --dla 'uconcat(",", <<{{x}} * 2>>)'
 
 Function Library
    ii_agg(<snippet>, <snippet>[, <snippet>])
    ii_aggregator(<snippet>, <snippet>[, <snippet>])
    inject_into_agg(<snippet>, <snippet>[, <snippet>])
    inject_into_aggregator(<snippet>, <snippet>[, <snippet>])
       Take an initial snippet, a combine snippet, and an optional squish snippet to produce an ad-hoc aggregator based on inject into. The initial snippet produces the aggregate value for an empty collection, then combine takes $a
       representing the aggregate value so far and $r representing the next record to add and returns the new aggregate value. Finally, the squish snippet takes $a representing the final aggregate value so far and produces the final
       answer for the aggregator.
 
       Example(s):
          Track count and sum to produce average:
             ii_agg(<<[0, 0]>>, <<[$a->[0] + 1, $a->[1] + {{ct}}]>>, <<$a->[1] / $a->[0]>>)
 
    for_field(qr/.../, <snippet>)
       Takes a regex and a snippet of code. Creates an aggregator that creates a map. Keys in the map correspond to fields chosen by matching the regex against the fields from input records. Values in the map are produced by aggregators
       which the snippet must act as a factory for ($f is the field).
 
       Example(s):
          To aggregate the sums of all the fields beginning with "t"
             for_field(qr/^t/, <<sum($f)>>)
 
    for_field(qr/.../, qr/.../, <snippet>)
       Takes two regexes and a snippet of code. Creates an aggregator that creates a map. Keys in the map correspond to pairs of fields chosen by matching the regexes against the fields from input records. Values in the map are produced
       by aggregators which the snippet must act as a factory for ($f1 is the first field, $f2 is the second field).
 
       Example(s):
          To find the covariance of all x-named fields with all y-named fields:
             for_field(qr/^x/, qr/^y/, <<covar($f1, $f2)>>)
 
    map_reduce_agg(<snippet>, <snippet>[, <snippet>])
    map_reduce_aggregator(<snippet>, <snippet>[, <snippet>])
    mr_agg(<snippet>, <snippet>[, <snippet>])
    mr_aggregator(<snippet>, <snippet>[, <snippet>])
       Take a map snippet, a reduce snippet, and an optional squish snippet to produce an ad-hoc aggregator based on map reduce. The map snippet takes $r representing a record and returns its mapped value. The reduce snippet takes $a and
       $b representing two mapped values and combines them. Finally, the squish snippet takes a mapped value $a representing all the records and produces the final answer for the aggregator.
 
       Example(s):
          Track count and sum to produce average:
             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 })
 
 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-collate <args> [<files>]
    Take records, grouped togther by --keys, and compute statistics (like average, count, sum, concat, etc) within those groups.
 
    For starting with collate, try doing single --key collates with some number of aggregators (list available in --list-agrregators)
 
 Arguments:
    --key|-k <keys>                 Comma separated list of key fields. May be a key spec or key group
    --dlkey ...                     Specify a domain language key. See "Domain Language Integration" below.
    --dlaggregator ...              Specify a domain language aggregate. See "Domain Language Integration" below.
    --aggregator|-a <aggregators>   Colon separated list of aggregate field specifiers. See "Aggregates" section below.
    --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 below.
    --cube-default                  See "Cubing" section below.
    --incremental                   Output a record every time an input record is added to a clump (instead of everytime a clump is flushed).
    --list-aggregators              Bail and output a list of aggregators
    --show-aggregator <aggregator>  Bail and output this aggregator's detailed usage.
    --ignore-null                   Ignore undefined or non-existant keys in records
    --filename-key|fk <keyspec>     Add a key with the source filename (if no filename is applicable will put NONE)
 
   Help Options:
       --help-aggregators     List the aggregators
       --help-all             Output all help for this script
       --help                 This help screen
       --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:
    Count clumps of adjacent lines with matching x fields.
       recs-collate --adjacent --key x --aggregator count
    Count number of each x field value in the entire file.
       recs-collate --key x --aggregator count
    Finds the maximum latency for each date, hour pair
       recs-collate --key date,hour --aggregator worst_latency=max,latency
    Find the median value of x+y in records
       recs-collate --dlaggregator "m=perc(50,snip(<<{{x}}+{{y}}>>))"
 
 Aggregates:
    Aggregates are specified as [<fieldname>=]<aggregator>[,<arguments>]. The default field name is aggregator and arguments joined by underscores. See --list-aggregators for a list of available aggregators.
 
    Fieldname maybe a key spec. (i.e. foo/bar=sum,field). Additionally, all key name arguments to aggregators maybe be key specs (i.e. foo=max,latency/url), but not key groups
 
 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 (which defaults to "ALL" but can be specified with --cube-default). This is not
    meant to be used with --adjacent or --size. If our key fields were x and y then we'd get output records for {x = 1, y = 2}, {x = 1, y = ALL}, {x = ALL, y = 2} and {x = ALL, y = ALL}.
 
 Domain Lanuage Integration:
    __FORMAT_TEXT__ The normal mechanism for specifying keys and aggregators allows one to concisely instantiate the objects that back them in the platform and is certainly the easiest way to use recs. The record stream domain language
    allows the creation of these objects in a programmatic way, with neither the syntactic issues of the normal way nor its guiding hand.
 
    The domain language is itself just PERL with a collection of library functions for creating platform objects included. Your favorite aggregators are all here with constructors matching their normal token. For convenience of e.g.
    last, aggregators are also included with a prefixed underscore.
 
    Below you can find documentation on all the "built in" functions. Most aggregators and deaggregators should be present with arguments comparable to their normal instantiation arugments, but with keyspec parameters replaced with
    valuations parameters.
 
    Either aggregates or keys may be specified using the recs domain language.
    Both --dlkey and --dlaggregator require an options of the format
    '<name>=<domain language code>'.  --dlkey requires the code evaluate as a
    valuation, --dlaggregator requires the code evaluate as an aggregator.
 
    See --help-domainlanguage for a more complete description of its workings
    and a list of available functions.
 
    See the examples below for a more gentle introduction.
 

=head1 See Also

=over

=item  L<RecordStream(3)> - Overview of the scripts and the system

=item  L<recs-examples(3)> - A set of simple recs examples

=item  L<recs-story(3)> - A humorous introduction to RecordStream

=item SCRIPT --help - every script has a --help option, like the output above

=back

