/formula

A simple extensible formula language for .NET

Primary LanguageF#MIT LicenseMIT

formula

A simple extensible formula language for .NET

Syntax

  • Arithmetic: + - * % / ^ ( )
  • Functions: FunctionName(Parameter, Parameter, ...)
  • Variables: VariableName OR [Variable Name With Spaces]
    • Ranges: VariableName|LowerExpr:UpperExpr| OR [Variable Name With Spaces]|LowerExpr:UpperExpr|
    • Indices: VariableName|IndexExpr| OR [Variable Name With Spaces]|IndexExpr|
  • Constants:
    • Number: 123.0
    • Boolean: true/false
    • Text: "A string"
    • Nothing: null
  • Branching: IF Expr THEN Expr ELSE Expr
  • Logical: = <> > < >= <= ! && ||

Examples

  • (1 + 2) * 3
  • SQRT(16)
  • MyVar * 2

Usage

  • From C#
    • CsWrapper.InterpretFormula("Test * 2", new Dictionary<string, double>() { { "Test", 1 } }, DefaultFunctionProvider.Instance)
    • CsWrapper.ParseFormula("Test * 2")
  • From F#
    • Formula.Parser.Parser.parseFormulaString
    • Formula.Parser.Interpreter.interpretFormula

Version History

1.1.0

  • IL emit based compiler
  • ExtractExpressionDependenciesWithRanges bug fix for partially resolved ranges

1.0.0

  • Bug fix for large expressions

0.13.0

  • Constant folder supports folding functions with constant arguments
    • Function implementations can declare they are deterministic
    • EmptyFunctionProvider created
  • Implicit cast from nullables fix/improvement

0.12.0

  • Support for 'Nothing' data type
    • Compiler & interpreter return an Option float value
    • C# wrapper returns Nullable
    • Handling of Nothing values in aggregation functions
  • IFunctionProvider returns typed results
  • 'null' keyword added

0.11.0

  • Parser detection of ranges used outside of function parameters
  • Remove implicit use of the first range value in operations

0.10.1

  • Bug fix for duplicate dependencies being returned from DependencyExtractor

0.10.0

  • Syntax support for offsets/indices on variables e.g. MyVar|1|
  • FIRST, LAST, MIN, MAX functions
  • Added FunctionValidator to validate function calls after parsing

0.9.0

  • Support escaped characters in string literals
  • Missing dependencies reported from dependency extractor with function defined ranges

0.8.0

  • Better parser error reporting - new ParserException
  • Position information reported from parser
  • Position information reported by dependency extractor

0.7.0

  • Syntax support for ranges on variables e.g. MyVar|1:5|
  • Range support for variable providers
  • Range dependency information
  • SUM, AVG functions

0.6.0

  • Typing changes to allow for typed function parameters - number, boolean, text

0.5.1

  • Target .NETStandard 2.0

0.5.0

  • Syntax changes
    • Support for escaping identifiers between []
    • Change function parameters to use ()

0.4.0

  • Financial functions
  • Dependency extractor
  • Composite IVariableProvider
  • Mutable IVariableProvider
  • Testing enhancements

0.3.0

  • Expression compiler
  • Branching & logical operators
  • Expression based IVariableProvider
  • Composite IFunctionProvider

0.2.0

  • Extension points for functions and variables
    • IFunctionProvider
    • IVariableProvider
  • Modulus function & operator
    • MOD
    • %

0.1.0

  • Support basic arithmetic
    • Addition/Subtraction
    • Multiplication/Division
    • Exponentiation
    • Negation
  • Handful of functions
    • SQRT
    • PI
    • POW
    • COUNT
  • Constant valued variables