Dear Haskellers, I am pleased to announce the latest release of ParserFunction. ParserFunction provides utilities for parsing and evaluating mathematical expressions. The central parsing function in this package is stringToExpr, which parses an expression (as a string) and returns an expression tree of type Expr (or nothing if the string is malformed). Example:
stringToExpr "cos(x^2)+4*(1+y)" Just (Add (Cos (Pow (Var 'x') (Num 2.0))) (Mul (Num 4.0) (Add (Num 1.0) (Var 'y'))))
Expressions can be evaluated using the function evaluateExpression. Example:
evaluateExpression "1+1" [] 2.0 evaluateExpression "exp(x)" [('x',1)] 2.718281828459045 evaluateExpression "sin(arctan(x))*sqrt(y)" [('x',1),('y',2)] 1.0
More information can be found by viewing the source code on Hackage. (http://hackage.haskell.org/package/ParserFunction-0.0.5) The functionality of this package provides the primary framework for several Haskell-based web applications found at (http://www.inputyourdata.com/mathematics.html). Comments and questions regarding this package or its implementation in web programming are welcomed. Regards, Enzo Haussecker University of California, San Diego Applied Mathematics Major Email: enzo [at] ucsd [dot] edu