Version History

Version ?: (released 2005/04/01)

Evaluator now swithchable to allow null variable values.
SymbolTable can now tell java.util.observers when new variables are created.
Changes in Error handling
New functions binom(n,i) binomial coeffs, conj(z) - complex conjugate

Version 2.3.1: (released 2006/01/27)

Fixed bug 1046349: bug in sum()
Fixed broken links in documentation
Fixed bug 1051988: JEPTester falsely reports "No errors"
Fixed documentation error 1358815: if - function is documented wrong
Added more tests for sum function
Updated build.xml to work with 1.5 JVMs

Version 2.3.0: (released 2004/10/03)

Switched from Java 1.1 compatibility to 1.2 compatibility
Documentation updates
Fixed batch script issues from beta 2

Version 2.3.0 beta 2: (released 2004/09/03)

2004/09/11: Renamed angle() function to atan2()
2004/04/12: New functions if, str, complex, polar.
2004/04/12: The ^ operator is now overloaded to be the cross product for 3D vectors as well as power.
2004/04/12: Various changes by Richard Morris (see DJEP Version History)
2003/08/15: Added new evaluation method that more than doubles evaluation performance
2003/08/15: Renamed addComplexVariable() and addVariableAsObject() to addVariable(). Now all three methods for adding different types of variables are named the same.
2003/08/10: Improved error handling and reporting in EvaluatorVisitor.

Known Issues:

Windows batch scripts for starting the examples are broken. This is due to switching from the MS JVM to the Sun appletviewer. Planned to be fixed for the 2.3.0 release.

Version 2.24: (released 2002/12/31)

2002/12/25: Fixed "not replacing escape sequences in strings" bug

Version 2.23: (released 2002/08/03)

2002/07/01: Started adding Number support to JEP class and functions
2002/07/08: Fixed string concatenation bug
2002/07/10: Added NumberFactory class and DoubleNumberFactory (with option for custom NumberFactory in JEP constructor)
2002/08/02: Added website documents to distribution

Version 2.22: (released 2002/07/04)

2002/06/06: Removed symbol table information from ASTVarNode (making AST nodes into pure data structure elements)
2002/06/20: Fixed sum() issue (functions with variable number of parameters)
2002/06/24: Rearranged function class structure by letting PostfixMathCommand implement PostfixMathCommandI (no changes to functionality)
2002/06/25: Added multiple thread testing classes
2002/06/26: Made EvaluatorVisitor non-singleton (was doing more harm than good)
2002/06/28: Added Unicode character support for variable names

VERSION 2.21: (released 2002/06/04)

2002/06/03: Fixed 1.1 compatibility issue in JEP.java (was using add() and clear() which are not included in the 1.1.8 VM).

VERSION 2.20: (released 2002/05/31)

2002/01/20: Combined multiplication and division to the same precedence level
2002/03/10: Added implicit multiplication, allowing expressions like "3x == 3*x"
2002/03/14: Improved evaluation performance through creating only one stack for evaluation
2002/03/19: Changes to operator precedence (more like C and Java)
2002/03/19: Now using JavaCC 2.1
2002/03/24: Added a console application to the org.nfunk.jepexamples package
2002/03/28: Implemented evaluation using the Visitor design pattern
2002/04/13: Added setAllowUndeclared() and setImplicitMul() for control of undeclared variables, and implicit multiplication options
2002/04/15: Added getSymbolTable() for obtaining list of variables in the symbol table (e.g. after parsing an expression with allowUndeclared=true)
2002/04/17: Prepared directory structure for building with ant
2002/04/19: Full transition of build environment to ant
2002/04/20: Finally was persuaded to add the sqrt() function to the set of built-ins
2002/04/27: Cleaned up error reporting using an error list in the JEP class
2002/05/27: New documentation
2002/05/30: Modifications to the sample applets

VERSION 2.12: (released 2002/02/01)

2001/08/31: Made a change to the Complex power function Complex.pow(to avoid problems with applets run in Internet Explorer (Math.exp(-Infinity) was not producing 0.0)
2001/09/10: Started working on array type
2001/09/20: Allowed variable number of arguments in functions
2001/09/20: Fixed undetected syntax error bug involving a comma before a list of function parameters
2001/10/17: Changed order of precedence for power and unary signs. Now power is of higher order than unary plus or minus
2001/11/10: Tweaked complex power functions
2001/11/10: Added error reporting for exceptions that occur while evaluating
2001/11/17: Edited the parser class to work without static function and symbol tables
2001/12/21: Completed the JEPTester class for verifying correct evaluation
2002/01/06: Replaced some Vector operations that relied on AbstractList with Java 1.1 compliant code

VERSION 2.11:

2001/08/26: Substituted the Netlib complex number class with a custom class

VERSION 2.10:

2001/07/07: Finished adding complex numbers, and incorporated complex numbers in nearly all built in functions
2001/07/08: Added string handling with concatenation with the + operator and comparison with ==
2001/07/16: Renamed the package to org.nfunk.jep
2001/08/24: Bugfix - subtraction of complex numbers was not working properly

VERSION 2.05:

2001/03/21: Fixed PostfixMathCommand class to allow inheritance to classes in other packages
2001/04/10: Added some error reporting functions to main interface class (Error name and position)
2001/06/01: Finished adding hyperbolic trigonometric functions and packaging.

VERSION 2.04:

2001/03/01: Fixed EOF problem (included EOF in grammar)
2001/03/16: Removed a few redundant exception classes

VERSION 2.03:

2001/02/17: Corrected order of precedence for logical operators
2001/02/17: Added '&&', '||', and '!' operators to extend the logical functionality of the parser
2001/02/07: Disabled the default command line output. For debugging purposes, you may want to try to use setTraverse(true)

VERSION 2.0:

2000/10/16: Started rebuilding the whole parser with JavaCC (http://www.webgain.com/products/java_cc/)
2000/10/27: Completed restructuring main background parser functions in JavaCC
2000/11/17: Created a simple interface class for intuitive interaction
2000/12/10: Added a few logical operators
2001/01/06: Released the freshly rebuilt parser

VERSION 1.1:

2000/11/30: Changed order of precedence so division occurs before multiplication
2000/10/01: Added exponential notation (i.e. 1.23e-3)
2000/10/16: Tweaked code here and there
2000/10/21: Finished new sample applet
2000/10/21: Repackaged and reorganized all source code and classes

VERSION 1.0:

2000/07/03: Added more documentation
2000/07/10: Removed all operator nodes such as MulNode or PlusNode, and replaced them by using FunNode nodes with PostfixMathCommands
2000/08/07: Considering using JavaCC to recreate the Parser
2000/09/01: Fixed multiple subtraction problem. Now 1-2-3 = (1-2)-3 instead of 1-(2-3)

VERSION 0.3:

2000/06/01: Created Web page and posted it
2000/06/02: Edited Web page, added one variable field just for integers
2000/06/06: Started adding internal code documentation
2000/06/09: Figured out how to create objects at run-time with the reflection package. Probably useful for future use of user defined functions
2000/06/10: Finished adding capability of parsing standard functions as well as user defined functions (thanks to Ross Bagely)

VERSION 0.2:

2000/06/18: Added SharedConstants class for the parser package
2000/06/18: Added InvalidExpressionException class which is thrown inside Parser
2000/06/19: Tweaked the error report of Parser
2000/06/27: Simplified process of adding user defined functions by adding a parent class PostfixMathCommand, that contains a function for checking the stack passed to the command
2000/06/27: Extended the FunNode class to be able to handle functions with multiple arguments, needs to be implemented in the parser yet
2000/07/01: Completed expanding parser to handle functions with multiple arguments. Implemented angle function to return the angle whose tangent is equal to the ratio of the arguments x/y (using the Math.atan2 method).