[ANN] alf 0.10.0 Released

Hi all! Alf version 0.10.0 has been released! This release brings lots of
new
features and enhancements as well as a fresh new documentation website
available at http://blambeau.github.com/alf.

Relational Algebra at your fingertips

* <http://blambeau.github.com/alf>
* <http://github.com/blambeau/alf>
* <http://rubygems.org/gems/alf>
* <http://rubydoc.info/gems/alf>

Alf brings the relational algebra both in Shell and in Ruby. In Shell,
because
manipulating any relation-like data source should be as straightforward as
a
one-liner. In Ruby, because I've never understood why programming languages
provide data structures like arrays, hashes, sets, trees and graphs but not
_relations_... Let's stop the segregation ;-)

Alf follows semantic versioning (http://semver.org/) and has not reached
its
first stable 1.0.0 release. Quoting semver.org: "Anything may change at any
time. The public API should not be considered stable". Including alf with
the
version requirement "~> 0.10.0" shouldn't break your code.

Changes:

# 0.10.0 / 2011-08-15

## New recognized data sources

* Alf now provides an Environment implementation on top of a SQL database.
  This means that SQL tables can now be used as data-sources. This feature
  relies on the sequel gem ('gem install sequel' is required), that drives
  recognized SQL servers. Then (don't forget that ALF_OPTS also exists):

      % alf --env=postgres://user:password@host/database show table

* Alf now recognizes and allows manipulating .csv files as first-class data
  sources. CSV output is also supported of course. Under ruby <= 1.9, the
  fastercsv gem is required ('gem install fastercsv' is required). Then:

      % alf restrict suppliers.csv -- "city == 'Paris'"    (input)
      % alf show suppliers --csv                           (output)

* Alf now recognizes and allows manipulating .log files as first-class data
  sources. This feature relies on request-log-analyzer gem that provides the
  parsers that Alf uses, and the log formats it recognizes
  ('gem install request-log-analyzer' is required). See examples/logs.

## New operators and enhancements

* A GENERATOR operator is introduced. It allows generating a relation with
one
  auto-number attribute, up to a given size.

* A COERCE operator is introduced. It provides a quick way to obtain
type-safe
  relations from type-unsafe sources like .csv files. For example:

      % alf coerce mydirtyfile.csv -- name String  price Float  at Time

  The coerce operator is of course available in Ruby as well:

      (coerce "mydirtyfile.csv", :name => String, :price => Float, :at =>
Time)

* The DEFAULTS (non-relational) operator now accepts default values as tuple
  expressions. When used in shell, provided default values are now evaluated
  that way. This allows specifying default values as being computed on the
  current tuple.

* Aggregations in the Lispy DSL must not be prefixed by Agg:: anymore.

## Miscellaneous enhancements

* Added 'alf --input-reader' to specify $stdin format (csv, rash, etc.)
* Added 'alf -Ipath' that mimics ruby's -I (add path to $LOAD_PATH before
run)
* Lispy#run supports command arguments to be passed as a string
* Lispy#run supports piped commands, with '|' as in shell

## Hurting changes to Lispy DSL (and therefore to Relation)

* The attribute-name syntax of aggregation operators has been removed. The
Agg::
  prefix must not be specified anymore.

      Agg::sum(:qty)    # !! error !!
      Agg::sum{ qty }   # !! error !!
      sum{ qty }        # simply, and only!

* The group aggregation operator has been removed. It will probably be
replaced
  in a future version. In the meantime, the GROUP relational operator
allows
  obtaining similar results.

* Lispy syntax of CLIP has changed (when used with --allbut option)

      (clip :suppliers, [:name, :city], true)
(before)
      (clip :suppliers, [:name, :city], :allbut => true)
 (after)

* Lispy syntax of DEFAULTS has changed (when used with --strict option)

      (defaults :suppliers, {:country => 'Belgium'}, true)
 (before)
      (defaults :suppliers, {:country => 'Belgium'}, :strict => true)
(after)

* Lispy syntax of GROUP has changed (when used with --allbut option)

      (group :supplies, [:sid], :supplying, true)
(before)
      (group :supplies, [:sid], :supplying, :allbut => true)
 (after)

* Lispy syntax of PROJECT has changed (when used with --allbut option)

      (project :suppliers, [:name, :city], true)
 (before)
      (project :suppliers, [:name, :city], :allbut => true)
(after)

* Lispy syntax of SUMMARIZE has changed (when used with --allbut option)

      (summarize :supplies, [:qty, :pid], {...}, true)
 (before)
      (summarize :supplies, [:qty, :pid], {...}, :allbut => true)
(after)

## Hurting changes in shell

* The attribute-name syntax of aggregation operators has been removed

      sum(:qty)   # !! error !!
      sum{ qty }  # works

* Shell syntax of GROUP has changed (option separator before introduced
name)

      % alf --text group supplies  -- pid qty supplying
(before)
      % alf --text group supplies  -- pid qty -- supplying
 (after)

* Shell syntax of WRAP has changed (option separator before introduced name)

      % alf --text wrap suppliers -- city status loc_and_status
(before)
      % alf --text wrap suppliers -- city status -- loc_and_status
 (after)

* Shell syntax of QUOTA has changed (--by and --order become pure arguments)

      % alf quota supplies --by=sid --order=qty -- position count sum_qty
"sum{ qty }" (before)
      % alf quota supplies -- sid -- qty -- position count sum_qty "sum{ qty
}"        (after)

* Shell syntax of RANK has changed (--order becomes a pure argument)

      % alf rank parts --order=weight,desc,pid,asc -- position
 (before)
      % alf rank parts -- weight desc pid asc -- position
(after)

* Shell syntax of SUMMARIZE has changed (--by becomes a pure argument)

      % alf summarize supplies --by=sid -- total_qty "sum{ qty }"
 (before)
      % alf summarize supplies -- sid -- total_qty "sum{ qty }"
 (after)

## Bug fixes

* [In shell] Options are now correctly parsed in presence of option
separators.
  That is, every argument after a '--' separator is considered a non-option
  argument.