setlX

 * notice
 + feature added, replaced or improved
 - feature removed
 # bugfix
                        

---v2.7.2--- 2019-06-03
# Raising 0 to the power of some negative number will result in some more useful exception

---v2.7.1--- 2018-10-15
 # Fix issue with parameter of setPenColor()
 # Unix launch script: prevent usage of rlwrap inside emacs

---v2.7.0--- 2017-10-03
 + add statistics library by Leon Mutschke and Jonas Siefker

---v2.6.1--- 2017-04-08
 + add la_hadamard(matrixA, matrixB) procedure
 # fix sorting with different number types: sort([1, 3, 2.0, 4.0])

---v2.6.0--- 2017-01-08
 + multiplication of matrix and vector will result in a vector instead of a matrix
 + the <==> operator is now a viral operation when terms are involved
                        

---v2.5.3--- 2016-11-26
 # fix modulo and integer division when negative numbers are involved

---v2.5.2--- 2016-11-01
 # fix bug that terms are not viral in Boolean operations
 + added varName to termUtilities library

---v2.5.1--- 2016-10-15
 # fix bug that doubles and rationals are regarded equal in too many cases
 * Note: now set of equal doubles and rationals will contain both values,
   instead of just one ({1.0, 1, 1} -> {1.0, 1} instead of just {1} or {1.0})
 + added procedure writeLibrary() that will (re)write the default library
   matching the running setlX version into the library path
 + added procedure writeExamples(directoryPath) that will (re)write the
   examples of the running setlX version into the supplied path

---v2.5.0--- 2016-10-01
 * Note: the setlX start scripts changed - please update yours!
 * Note: setlX now requires Java7 or higher to run
 + Changed confusing matching of variables and functions
   * removed quote expression ('@')
   + terms must start with an at symbol ('@') instead of an upper case letter
   + variables can start with upper case letters
   + added isVariable(term) function, that tests if given term represents a variable
   * 'internal' terms start with three at symbols ('@@@') instead of one
   * please (re)read related sections in tutorial for more details and clarifications
 + forall and exists will set their iteration variables to om, when forall == true and exists == false
 + added standard library files that are distributed with the interpreter
 + accessing the members of a matrix will return a vector instead of a list
 # fixed minor bug in plotting functions

---v2.4.3--- 2016-08-01
 # fix version number
 # fix building 1.6 compatible version when tests are enabled

---v2.4.2--- 2016-07-21
 # prevent concurrent modification during iterations

---v2.4.1--- 2016-07-03
 # Fix error handling when trying to modify collection during iteration

---v2.4.0--- 2015-07-05
 + added plotting functionality

---v2.3.4--- 2015-02-11
 # fixed matrix ** 0 computation
 # return more intuitive result for la_eigenVectors
 # removed error on empty closures

---v2.3.3--- 2014-12-14
 # fixed operator associativity
 # hopefully final rework of stack handling

---v2.3.2--- 2014-10-26
 + implemented lambda closures (e.g. x |=> y )
 # reworked stack handling

---v2.3.1--- 2014-10-13
 # minor performance fixes
 + updated tutorial

---v2.3.0--- 2014-10-09
 + implemented matrix functionality
 + separated closures and procedures; normal procedures do not have closure functionality
 + allow to access relations with multiple parameters without explicitly wrapping those
   parameters into a list, e.g.
   r[[a,b]] := 1; print(r[[a,b]]);
   may now be written as
   r[a,b] := 1; print(r[a,b]);
 + added specification of optional and unlimited parameters for procedures, closures and classes
 + added ability to expand lists as arguments for function calls

---v2.2.4--- 2014-06-09
 + added "getClass()" method to objects, that refers to the class used to create
   that object
 + improve print() of predefined functions when they have optional parameters
 # fix some error messages when trying to perform operation on om
 # fixed some internal issues with comparing objects and classes

---v2.2.3--- 2014-04-07
 + updated tutorial
 + add --harshWelcome option, that reduces the welcome message
 + allow combination of short command line options
 + improve call and member access error messages
 # fix empty regular expression capture groups being returned as string "null",
   now they are returned as om

---v2.2.2--- 2014-02-19
 + implemented >< operator on lists, which combines two lists of equal size into
   a list of pairs, one from each list
 + implemented closures as special kind of procedure for future use; currently
   closures work exactly like normal procedures
 + improve ask() on PCs when there is just one answer
 + updated to antlr 4.2
 # fixed closure behavior with cachedProcedures calling themselves recursively
 * as 'closure' is now a keyword, code using it as an identifier will break

---v2.2.1--- 2014-02-03
 + added getOsID() function that returns an identifier for the operating system
   that setlX runs on
 + added ask(question, answers) function that prompts the user with `question',
   then forces him to select one from answers, which is returned
 + allow negative indexes to strings and lists, which count from the end

---v2.2.0--- 2013-08-14
 + added a do-while statement
 + added 64 bit floating point values that behave according to IEEE
   754
 + added the function double() that converts a string or number into a
   floating point number
 + added the function isDouble() that checks whether the value is a
   floating point number
 - removed the function real and isReal
 # min and max can now only be applied to lists or sets of numbers.
 * build for Java 1.6 by default

---v2.1.1--- 2013-07-27
 + the single straight quote is now used as escape character in literals and the
   only valid escape sequence is two quotes ('') as sequence for a single one (')
 - the quote operator (@) looses its special meaning for double-quoted strings;
   it will now only force a term creation; to get the old behavior on strings,
   replace the quotes with single straight ones: @"tax: 3$"  ->  'tax: 3$'
 # fix string escape level and error handling in split() function
 * term representation of strings changed
 * build for Java 1.6 by default

---v2.1.0--- 2013-07-01
 + added short versions for some command line options
 + provide better fallback when comparing objects without 'equals' member to other
   types
 - remove "short-iterate" syntax to resolve some issues in the grammar
   (i.e {x in set | x%2 == 0} needs to be replaced with {x : x in set | x%2 == 0})
 * lots of internal changes to the build system and error handling

---v2.0.2--- 2013-05-18
 - removed partly defunct debug functions (but not trace)
 + add ability to trace object and class members
 + add very simple debugging function stop(id)

---v2.0.1--- 2013-04-28
 # removed redundant quotes in objects
 # refactor and improve trace functionality

---v2.0.0--- 2013-04-11
 + updated the tutorial to reflect the major new features
   (basic object orientation and graphics support)
 + all Boolean operators are overloadable

---v1.6.1--- 2013-04-07 (unreleased)
 + added resetRandom() function, which reseeds the random number generator
 + improve automated tests to include term conversion

---v1.6.0--- 2013-03-24 (unreleased)
 + integrated graphics library by Markus Jagiella
 * Note: setlX launcher scripts need to be updated
 + some performance improvements
 * refactored Boolean expressions and some other bits and pieces

---v1.5.1--- 2013-03-10 (unreleased)
 + add syntax highlighting definition for gedit
 + moved SETLX_LIBRARY_PATH definition into launcher script
 + updated antlr to v4.0, which should improve parser error messages
 + simplified PreDefinedFunction API a little bit
 # fixed some PDF layout issues

---v1.5.0--- 2013-02-23 (unreleased)
 + added hypot(numberValue, numberValue) and atan2(numberValue, numberValue) functions
 + make predefined math-functions (e.g. exp(x), sin(x)) overloadable in objects
 + eliminated explicit "this" parameter for object-methods
 + add engineering and plain mode for printing reals
 # fix some bugs when accessing methods of objects
 # fix crash of optimizer when code contains syntax errors

---v1.4.99999--- 2013-02-12 (unreleased)
 + removed global definitions ('var')
 + changed class definition syntax

---v1.4.9999--- 2013-02-10 (unreleased)
 + added nCPUs() functions, returning the number of CPUs (/cores) in the system
 + allow overloading of more functions for objects

---v1.4.999--- 2013-02-05 (unreleased)
 + implementation of object orientation extension almost feature complete
   (missing a number of overloadable operators)

---v1.4.99--- 2013-02-03 (unreleased)
 + first iteration of object orientation extension
 + use multithreaded test script
 + add latex source for tutorial
 + print results of --ev and --ex options without sugar coating
 # fix infinity when used as parameter for predefined math functions
 # fix some issues in the grammar

---v1.4.5--- 2013-01-13
 + more robust internal handling of reals
 + improved stack management
 # fix conversion from infinity to double
 # fix range selection of lists, when range is out of bounds
 # fix and update various scripts

---v1.4.4--- 2012-12-25
 + switched to BSD license
 # fixed associativity of => operator during term-conversion/print
 # fix some error messages

---v1.4.3--- 2012-12-13
 + updated the development documentation
 + allow powerSet computation by using the set as exponent, e.g. 2 ** {1,2,3}
 + added mathConst("Infinity")
 + m ** 2 computes the cartesianProduct of m, if m is a set
 # fixed multiple "internal errors"
 # fix error message for calls

---v1.4.2--- 2012-11-13
 + updated the tutorial
 # fixed --help option

---v1.4.1--- 2012-11-10
 + allow assignment of indexable collection values (e.g. lists, strings, terms) to
   lists of IDs (e.g.  [a,b,c] := Term("foobar",99,sin);  )
 + improved closure detection
 + added --ev and --ex options to directly execute an expression or statement
 # fix char position variable in default branch of scan statement

---v1.4.0--- 2012-10-06
 + added closures

---v1.3.3--- 2012-09-30
 + added matches(string, pattern [, captureGroups]), replace(string, pattern, replacement),
   replaceFirst(string, pattern, replacement) functions
 # better explanation of errors in comparisons

---v1.3.2--- 2012-09-05
 # fixed escaped single straight quote in literal strings (only handled escape sequence)
 + allow pattern in regex-branch to be an expression
 + added variable to scan statement, which stores a map of positions
   where first matched character is located inside the input-string
 * replaced '->' with 'as' in regex branches

---v1.3.1--- 2012-09-01
 # fixed error handling in nested parsing runs (e.g. $-expressions in strings, parse())
 + added regex-branch to match
 + added scan statement
 + added literal strings enclosed in single straight quotes, which are transferred
   from source into memory without parsing escape sequences or interpreting the content
   in any way. While "\n" describes a string of one linebreak character, '\n' describes
   a string of the two separate characters: backslash and n.
 + allow explicit lists/sets with rest as normal expression, not only in match
 + more powerful matching using explicit lists/sets with rest
 + added >< operator to compute the Cartesian-Product of two sets

---v1.3.0--- 2012-08-22
 # fixed product of a number and a list
 + added tutorial.pdf
 + updated documentation

---v1.2.9--- unreleased
 + get() and read() will not add anything extra when supplying a user defined prompt
 # fixed errors during certain operations on reals

---v1.2.8--- unreleased
 # fixed from(string)
 # fix isMap()

---v1.2.7--- unreleased
 + added clearCache(cachedProcedure) function
 + added check and backtrack statements
 # fixed ceil and floor for integer reals (e.g. 2.0, -2.0)
 + iterations like:
      for ([x,y] in s, [y,z] in t) {}
   now work like
      for ([x,y1] in s, [y2,z] in t | y1 == y2) {}
   i.e. same variables must contain same values to execute the iteration block

---v1.2.6--- unreleased
 + added cached procedures (Keyword: cachedProcedure instead of just procedure)
 + added cacheStats(cachedProcedure) function
 + fixed issues with matching negative numbers
 + allow conditions in for-loops

---v1.2.5--- unreleased
 + added isNumber() function, which is equal to (isRational() || isReal())
 + brackets are transparent in terms

---v1.2.4--- unreleased
 + added optional Boolean conditions to match branches
 # match correctly when using the same variable multiple times in a single match branch
 + lots of refactoring

---v1.2.3--- unreleased
 # fixed matching strings using lists of variables
 + improved performance of collect

---v1.2.2--- 2012-08-01
 + changed rnd() to require second `numberOfChoices' parameter when used with rationals
 + added optional parameter to random()
 + added collect() function

---v1.2.1--- 2012-07-23
 + improved performance of forall/exist when used in loops
 + somewhat improved performance of variable look-ups
 + added run(command) function
 + added isPrime(integer) function
 + rnd() now also takes number as argument, returning a random number between
   0 and the argument (inclusive) -- works for negative numbers as well

---v1.2.0--- 2012-07-17
 # fixed minor bugs in string-representation of some statements
 # forall and exist can be used in combinations with other Boolean expressions
 # renamed --args option to --params, to avoid conflicts with args() function
 * params variable will now be present, but empty if --params option is not used
 + added nPrint() and nPrintErr() functions, which do not add a new line
 + support % operator for sets, computing the symmetric difference, e.g. {1,2} % {1,3} = {2,3}
 + support * for lists, multiplying their contents
 + added toUpperCase(string), toLowerCase(string), startsWith(string, prefix),
   endsWith(string, suffix), trim(string) and join(collection, separator) functions
 * renamed strSplit() to split()
 + split() now also works for lists
 + added isProbablePrime(int) and nextProbablePrime(int) functions
 + added nextPermutation(list), sort(listOrString), shuffle(listOrString) functions
 # fixed handling of Boolean expressions by the parser
 + match conditions respect preset variables
 + added perfomance test
 + added UNSUPPORTED profiling script to development distribution

---v1.1.1--- 2012-07-10
 # fixed bug with indirect assignments not working in all cases

---v1.1.0--- 2012-07-09
 + fixed performance issue with break and continue statements
 + fixed performance issue with indirect assignment types (`+=', `-=', `*=')
 + added integer division assignment ( '\=' )
 - removed assignment chaining for everything but the direct assignment (i.e. `a := b := "foo"')
 + strings are collections now ( try `for(c in "foo") {..}' or `first("foo")')
 + "prolog-style" list match works with strings
 # faster 2nd+ time look-up of undefined variables
 # fixed precedence of power operator ( ** )
 + add --args option, which passes all following options to the SetlX program (using variable `args')

---v1.0.2--- 2012-07-03
 + fixed performance issue with return statements

---v1.0.1--- 2012-07-01
 * adding om to a string (e.g. "" + om) will now result in an error
 * +/[] and */[] return om, not 0 or 1 respectively
 + added binary forms of +/ and */ operators to specify neutral element
 # fixed parsing rules for reals and ranges
 + added compare(valueA, valueB) function
 + added strSplit(string, pattern) function
 + added reverse(collectionValue) function
 + improved performance of lists (in most cases)
 * input in interactive mode is now accepted WITHOUT entering an empty line
 + newline can be escaped by adding a backslash before pressing [Enter]
 + added --multiLineMode option and multiLineMode() function to restore previous behavior
 + added loadLibrary() function, loading files from SETLX_LIBRARY_PATH environment variable
 + added --libraryPath option to override SETLX_LIBRARY_PATH

---v1.0.0--- 2012-06-10
 * updated documentation

---v0.7.8--- 2012-06-06
 * output of results in interactive mode will only be displayed for last statement
 * output added by the interpreter is enclosed in ~< >~
 + added trace() function to print assignments

---v0.7.7--- 2012-06-01
 + added optional parameter `msg' to read(msg) and get(msg)
   `msg' will be displayed in front of the prompt
 + added fileAPI (i.e. readFile(), writeFile(), appendFile(), deleteFile())
 + added function mathConst(name) to retrieve "e" and "pi"
 - e and pi are not defined as global variables anymore

---v0.7.6--- 2012-05-26
 # suppressed duplicate parser error messages
 + new random() function returning a random real:    0.0 <= random() <= 1.0
 + updated aStar examples
 + introduced some more platform independence (in preparation for Android version)
 + code cleanup

---v0.7.5--- 2012-05-16
 + added \ operator for integer division, e.g. a \ b == floor(a/b)
 + round() works for unlimited precision values

---v0.7.4--- 2012-05-12
 + implemented matching for sets
 + implemented splitting lists and sets in match
 + added permutations() function
 + added sleep() function
 + updated development manual
 # fixed bug when reading from stdin
 * renamed examples folder

---v0.7.3--- 2012-04-26
 + added assert function and option to disable assertions
 + updated aStar hanoi examples

---v0.7.2--- 2012-04-22
 * initial change log entry