Tiny Expression Evaluator (or TinyEE) is a simple expression language running on .NET's Dynamic Language Runtime.

Its main strengths are:

1. Simple syntax: everything is an expression that returns a value. There is no looping, assignment or side-effect to worry about.
2. Easy to use and integrate with other system. The dll is tiny and there is no external dependency other than the core .NET framework

It's designed to be a power tool for domain experts to define rules and calculations that augment an existing system.

##Quick start The easiest way to use TinyEE is to call its static method Tee.Evaluate(expression) :

TEE.Evaluate("2^20") //returns 1048576

To use variables in your expression, pass in an object as the second parameter (dictionary and callback delegate are also supported).

TEE.Evaluate("z = (x+y)^3 = x^3 + 3*x^2*y + 3*x*y^2 + y^3", new{x=3,y=2,z=125})
//returns True

For cases when an expression is evaluated multiple times (such as in a plotting app), you can improve performance using cached compilation. The struct returned by Compiled() holds a reference to a compiled delegate, which can be invoked repeatedly without incurring any parsing overhead:

var expr = parsedExpr.Compile("x^3 + 3*x^2*y + 3*x*y^2 + y^3");//compiled
var result1 = expr.Evaluate(new{x=2,y=3});//result1 = 125
var result2 = expr.Evaluate(new{x=5,y=4});//result2 = 729

To get the list of variables in an expression, get a ParsedExpression:

var parsedExpr = TEE.Parse("z = x^3 + 3*x^2*y + 3*x*y^2 + y^3");
var variables = parsedExpr.Variables;//variables = [z,x,y]

##Syntax Reference The syntax borrows a lot from C#, JavaScript and Excel formula. When in doubt, there are 2 things to remember:

• Everything is a value expression.
• Everything is dynamic.

Literal data types

Basic Arithmetics

Comparision

Logical

Object

Branching

Chaining and nesting Almost all expression can be chained or nested.

• Property and indexer:

table01A.Rows[3]["col3"]

• Function call:

100>10 ? Sum(Max(1,2),Max(0,1),Max(-5,3)) : Sum(Min(-2,-3),Min(1,2))

• Comparision:

x > y > z

• Conditional:

condition1
    ? "value 1"
    : condition2
        ? "value 2"
        : "value 3"

Operator precedence and associativity

The following table shows all operators in order of precedence from highest to lowest:

All expressions are evaluated from left to right. The expression 2^2^2^2, for example, is evaluated as ((2^2)^2)^2 == 256 (same as in C# and Excel (but differs from Mathematical convention))

##Main APIs

##Benchmark //TODO

##Credits TinyEE's parser and scanner are generated by Herre Kuijpers's excellent Tiny Parser Generator. All thanks go to him.

##License MS-PL