Spreadsheet::Engine is a Modified Version of SocialCalc 1.1.0, which in
turn started as modifications to the wikiCalc(R) program, version 1.0.

wikiCalc 1.0 was written by Software Garden, Inc.

Portions (c) Copyright 2007, 2008 Tony Bowden
Portions (c) Copyright 2007 Socialtext, Inc.
Portions (c) Copyright 2005, 2006, 2007 Software Garden, Inc.

Numerous tests are adapted from the Open Formula specification.
Copyright (c) 2006 OASIS 2006. All Rights Reserved.

Changes from the Standard Version (SocialCalc 1.1.0) are detailed below.

== v0.14 ==   (January 22, 2008)

Summary: Better testing, more extraction

 - Tests
   -- Only do numeric comparisons if we want and *got* a number
      (this silences warnings when we want a number but don't get one)
   -- Add accurate tests for TODAY() and NOW() based on time 
      (Open Formula spec can't do this)

 - Functions
   -- Extracted functions TODAY(), NOW()
   -- Extract and simplify MATCH(), VLOOKUP(), HLOOKUP()

== v0.13 ==   (January 21, 2008)

Summary: Restructuring

 - Functions
   -- Moved base classes from Function/ to Fn/
       Function/ is now just for packages that are spreadsheet functions
       and Fn/ for helper classes (including base classes)
   -- Extracted logical.pm baseclass
   -- Extracted functions IF(), AND(), OR(), NOT(), EXACT(), CHOOSE(),
     -- Simplify EXACT() by pre-sorting operands by type
     -- Simplify IF() into a trivial ternary
   -- Rewrite depreciation functions
   -- Extracted Fn/Approximator for Newton-Raphson approximations
   -- Added temporary(?) top_of_stack method to base.pm
   -- Removed ability for 'series' functions to return a listref

== v0.12 ==   (January 19, 2008)

Summary: Harmonise operand handling in Functions

   -- Promote string arg handling to standard 'signature' method
   -- Replace math arg handing with new signature approach
   -- Allow functions to declare a maximum number of args
   -- optype() doubles up a single argument if required
   -- Miscellaneous tidying of other arg handling code
   -- Corrected LEFT() and RIGHT() to take exactly 2 args 
   -- Corrected investment functions to require at least 3 args 

 - Function/*.pm
   -- next_operand_as_text now automatically upgrades to utf8
   -- Extracted (and simplified) ROUND() function
   -- Extracted LOG() function
     -- Corrected LOG() to default to base 10 (was natural log)
   -- math2.pm is now a subclass of math.pm
   -- remove no longer necessary dates.pm 

== v0.11 ==   (January 17, 2008)

Summary: Value objects

 - Created Value, Error, and Operand classes (and rewrite to use them)

 - Function/*.pm
   -- Extracted depreciation.pm and investment.pm baseclass
   -- Extracted functions N(), T(), VALUE(), DDB(), SLN(), SYD(),
      FV(), NPER(), PMT(), PV(), RATE(), NPV()

 - Function/base.pm
   -- Added optype() method (and rewrite other methods to use it)

== v0.10 ==   (January 16, 2008)

Summary: Pluggable date and time functions

 - Function/*.pm
   -- Extracted hms.pm, ymd.pm and dates.pm baseclasses
   -- Extracted functions DAY(), MONTH(), YEAR(), WEEKDAY(), DATE(),
      HOUR(), MINUTE(), SECOND(), TIME()
   -- More refactoring of error handling (several functions now give
      generic 'invalid arguments' errors rather than function specific 

== v0.09 ==   (January 15, 2008)

Summary: Further abstraction of functions

 - Function/base.pm
   -- Abstract execute() up and delegate to result() in subclasses
   -- Add next_operand / next_operand_as_text/number
     -- rewrite other classes to use these

 - Function/*.pm
   -- Extracted is.pm baseclass
   -- Extracted functions ERRCELL(), FALSE(), ISBLANK(), ISERR(), 
      NA(), PI(), TRUE()

 - Functions.pm
   -- simplify function delegation list

 - Tests
   -- add t/fn_args.t (and fix math/math2 argument checking)

== v0.08 ==   (January 6, 2008)

Summary: Pluggable math functions

 - Function/*.pm
   -- Extracted math.pm and math2.pm baseclasses
   -- Extracted functions ABS(), ACOS(), ASIN(), ATAN(), COS(),
      DEGREES(), EVEN(), EXP(), FACT(), INT(), LN(), LOG10(), ODD(),
      RADIANS(), SIN(), SQRT(), TAN() 
   -- Extracted functions ATAN2(), MOD(), POWER(), TRUNC()
   -- Extracted functions FIND(), LEFT(), LEN(), MID(), PROPER(),
   -- Allowed MID() to accept a zero length per OpenFormula spec

 - Spreadsheet::Engine::Sheet
   -- Removed straggling reference to obsolete definitions file

 - Tests
   -- POD coverage test now uses CountParents
   -- removed t/stringfn2.t (obsoleted by OF tests)

 - General
   -- Style tweaking per perlcritic

== v0.07 ==   (January 1, 2008)

Summary: Open Formula test cases

 - Tests
   -- Set up t/data/openformula-testsuite.txt from Open Formula spec
   -- Create t/lib/SheetTest.pm helper and rewrite tests to use it
   -- Replace t/dsum.t with t/of-criteria.t
   -- Add t/of-autonum.t, t/of-colrows.t, t/of-conversions.t,
      t/of-count.t, t/of-database.t, t/of-datetime.t, t/of-errors.t,
      t/of-financial.t, t/of-is.t, t/of-limits.t, t/of-logical.t,
      t/of-lookup.t, t/of-math.t, t/of-names.t, t/of-numbers.t,
      t/of-operators.t, t/of-params.t, t/of-references.t, t/of-rounding.t,
      t/of-stats.t t/of-strings.t, t/of-value.t t/of-whitespace.t
   -- Add test coverage summary as coverage.txt

 - Spreadsheet::Engine::Sheet
   -- Silence $fractionvalue warnings in format_number_with_format_string
   -- Silence $oldrate warnings in interest_functions and irr_function
   -- Silence $offsetvalue and $previousOK warnings in lookup_functions
   -- Silence $rawvalue warnings in determine_value_type
   -- Silence $tostype warnings in evaluate_parsed_formula

 - Spreadsheet::Engine::Functions
   -- Silence warnings from substr() when given weird paramaters

== v0.06 ==   (December 23, 2007)

Summary: Pluggable series functions 

 - Function/*.pm
   -- Extracted base.pm root baseclass
   -- Extracted series.pm and counter.pm baseclasses
   -- Extracted functions COUNT(), COUNTA(), COUNTBLANK()
   -- Extracted functions SUM(), MIN(), MAX(), AVERAGE()
   -- Extracted functions VAR(), VARP(), STDEV(), STDEVP()

 - Tests
   -- Add series.t

== v0.05 ==   (December 18, 2007)

Summary: Pluggable text functions 

 - Spreadsheet::Engine::Functions
   -- Document new way of adding UDFs

 - Function/*.pm
   -- Extracted text.pm baseclass
   -- Extracted functions UPPER, LOWER, LEN

 - Tests
   -- Add stringfn2.t

== v0.04 ==   (December 14, 2007)

Summary: Fix cpantesters problems

 - General
   -- Set minimum perl version to be 5.7.3 (this is the first perl version
      with suitable unicode support. In theory this could work with earlier
      perl versions if sheet data was restricted to ascii. YMMV)

 - Spreadsheet::Engine::Sheet
   -- Fix hash slice syntax that no longer works in 5.10 (Slaven Rezik)

 - Spreadsheet::Engine::Functions
   -- use Encode::encode/decode rather than utf::encode/decode

 - Tests
   -- Rename formatting.t to fmt_date.t
   -- Add fmt_num.t

== v0.03 ==   (December 13, 2007)

Summary: provide basic interface via Engine.pm

 - Engine.pm
   -- Add new(), exeute(), ecalc(), raw(), load_data()

 - Spreadsheet::Engine::Storage::SocialCalc
   -- Created from SocialCalc::DataFiles

 - Tests
   -- Rewrite tests to use new Engine interface
   -- Add stringfns.t

== v0.02 ==   (December 12, 2007)

Summary: silence warnings exposed by test suite

 - Sheet.pm
   -- Rename special_chars() to html_escape()
   -- Ensure values are initialised in format_number_with_format_string()
   -- Silence warnings from format_value_for_display(),
       step_through_range_down(), execute_sheet_command() 
   -- Tidy parse_header_save(), recalc_sheet()
   -- Shortcircuit empty commands in execute_sheet_command() 
   -- Shortcircuit empty lines in parse_sheet_save()
   -- Remove unnecessary use of Time::Local

 - Functions.pm
   -- Silence warnings from dseries_functions(), countif_sumif_functions()

 - Tests
   -- Add tests circular.t, cutpaste.t, dsum.t, header.t
   -- Add SUMIF() test to commands.t

== v0.01 ==   (December 11, 2007)

Summary: Created from SocialCalc 1.1.0

 - General
   -- Renamed and rearranged files 
   -- Reformatted code 
   -- Turned comments into POD
   -- Created all test files
   -- Inlined all strings and formats from Strings.pm 
      (i18n and l10n be damned, for now anyway)

 - Functions.pm
   -- Removed WKCHTTP() function
   -- Renamed WKCERRCELL() to ERRCELL()
   -- Renamed WKCHTML() to HTML()
   -- Renamed WKCTEXT() to PLAINTEXT()
   -- Made %Functions::function_list our() rather than my() for easier

 - Sheet.pm
   -- Removed display functionality
   -- Remove wikitext formatting
   -- Remove ability to fetch related sheets over HTTP