EquationEvaluator 1.2 
A REALbasic plugin for Runtime Mathematical Expression Evaluation This is both a PPC and a Carbon/OS X Plugin. EquationEvaluator is based on Robert Douglas' Macintosh port of Mark Morley's Expression Evaluator (which can be found in DOS code repositories under the name CEVAL). This REALbasic version is a plugin with just one function that takes a string (a mathematical expression) as an argument and returns a double. Supported mathematical functions include:
Instructions:You give the function (called JEE) a string with the expression you would like evaluated, and it will return the value as a double. The variable assignment feature makes it possible to assign up to 50 variables (each with a name up to 15 characters long). You can assign the variables before you give the expression (as in "x=3, y=2, x+y") or in the middle of an expression (as in "3+(x=4) + x" which should return 11). Or you can have an expression evaluated as part of the assignment, and used later on in another expression (as in "x=3, y=x+2, x+y" which returns 8). Note that if you do the assignment before the expression then you need to follow the assignment with a comma (,) so that the parser knows where the assignment stops and the expression begins. EquationEvaluator follows the standard math rules for determining which operations go first (multiplication/division before addition/subtraction, etc.). You can also group parts of your expression with parentheses ( "(" and ")" ) if you want to be sure of the order of operations. Warning: EquationEvaluator does not evaluate scientific (powers of ten) notation. If you try this assignment "x=3E5" (meaning "x=300000"), EquationEvaluator will become confused and will not return the correct value (probably it will return 0). The best solution is to preprocess any strings with scientific notation so that they replace the "E" with "*10^" (so our assignment above would be "x=3*10^5"). Examples:JEE("7+11*5") returns 62 Download:Download EquationEvaluator here More:You can see a review and comparison of all of the runtime expression evaluating options available for RB users on my RB Math Stuff page. Or visit REALbasic's web site at www.realbasic.com Return to Tamara's Homepage
