This project is a simple mathematical expression parser written in C#. It's the refactoring of an old project and uses an AST-evaluation algorithm. You can use built-in or add your functions and variables to global scope. It was written primarily for fun and and as programming exercise; anyway if you anyone find it useful, please send feature requests or issues; but please take note that this is still a work in progress.
At the moment specification is just a draft.
MonoDevelop or Visual Studio.
var contex = new Context()
.SetVariable("G", 6.67428D)
.SetVariable("earth_mass", Evaluate.As<double>("5.97219 * pow(10,24)")) // 5.97219E+24 kg
.SetVariable("lunar_mass", Evaluate.As<double>("7.34767309 * pow(10,22)")) // 7.34767309E+22 kg
.SetVariable("perigee_dist", 356700000D) // moon-earth distance at perigee in m
.SetFunction("calc_force", (object[] args) => ((double) args[0] * (double) args[1]) / Math.Pow((double) args[2], 2));
var result = contex.EvaluateAs<double>("G * calc_force(earth_mass, lunar_mass, perigee_dist)"); // 2.3018745174107073E+31
bool isGCorrect = contex.EvaluateAs<bool>("G == 6.67428");
- String literals fully implemented.
- Version policy changed.
- First changes to lexer for handle string literals.
- Refactoring, ExpressionEvaluator splitted in
Context
(as the name, evaluation with context) andEvaluator
(static helper, contextless evaluation). - Added support for exponent in numeric literal
([E|e][+|-][DIGIT])
. - Parser class aligned to new grammar.
- BNF grammar changed (see Evaluator.grm).
- Operator
^
(exponent) removed. Will be used as bitwise operator. - Introduced relational operators
(==, !=, <, >, <=, >=)
. - Introduced
true
andfalse
literals. - Heavy internal refactoring toward a new design.
- Evaluation provided via both instance and static methods.
Giacomo Stelluti Scala