math_expressions

Added

• Add support for implicit multiplication to GrammarParser.
• Add useTraditionalMathDefinitions option to RealEvaluator to return double.nan for mathematically undefined operations (e.g. division by zero, 0^0, tan(pi/2)) instead of following Dart's default floating-point behavior.

Changed

• Require Dart 3.8.
• Update petitparser dependency to 7.x.

Added

• Add support for listing all variables in an Expression with the VariableCollector visitor. #73

• Add support for evaluating an Expression with the visitor interface: RealEvaluator (as real number), IntervalEvaluator (as interval), VectorEvalutor (as vector). This offers a strongly typed interface and replaces Expression.evaluate():

  // Old
  dynamic result = expression.evaluate(EvaluationType.REAL, context);
  
  // New
  var evaluator = RealEvaluator(context);
  int result = evaluator.evaluate(expression);
  

Changed

• The Rootfunction now accepts an Expression as degree.
• Handler functions passed to AlgorithmicFunction can no longer be dynamically typed.

Deprecated

• The Expression.evaluate() method. Use RealEvaluator instead.

Added

• Rewrite of the expression parser, available as GrammarParser.
  • Add support for constants: e, pi, ln10, ln2, log10e, log2e, sqrt1_2 and sqrt2.
  • Custom constant symbols are supported via ParserOptions.
  • Identifier naming is more restrictive. Names must start with a letter or $, followed by any number of word characters (letter or digit).
  • This library now depends on petitparser.

Deprecated

• The old expression parser is now deprecated. It is still exposed under the type alias Parser to maintain backwards compatibility.

Fixed

• Exception when define variable Number with character "e" #82
• Suppress conversion into e function #61
• Variables should resolve before keywords. #31

Added

• Add support for additional constants to GrammarParser: ln10, ln2, log10e, log2e, sqrt1_2 and sqrt2.
• Add ability to specify custom constants through ParserOptions: This enables parsing of constant symbols that do not match the allowed variable identifier naming schema.

Added

• Add support for n-th root function to GrammarParser.

Fixed

• Tighten dependency constraints to fix issue with lower bounds dependencies.

Added

• Add a modern grammar-based expression parser. This is opt-in at this stage, and can be used by instantiating a GrammarParser instead of the legacy Parser. The new parser fixes some long-standing issues with expression parsing, but is still missing a few features that were previously supported by the legacy parser:
  • Implicit multiplication is not supported yet.
  • Parsing of the n-th root function is not supported yet.
  • Identifier naming is more restrictive, names must start with a letter or $, followed by any number of word characters (letter or digit). This is mostly relevant for user-provided identifiers (algorithmic functions and variables).
• Add support for parsing constants, with initial support for piand e (Euler's constant). #26

Deprecated

• Renamed the existing expression parser to ShuntingYardParser. This parser is now in maintenance mode and will not receive any new features. Parser remains as a deprecated type alias to this legacy implementation to maintain backwards compatibility.

Fixed

• Exception when define variable Number with character "e" #82
• Suppress conversion into e function #61
• Variables should resolve before keywords. #31

Added

• Add parser support for implicit multiplication (thanks juca1331)

Changed

• Drop support for Dart SDK versions below 3.1.0

Added

• Add support for parsing variables containing digits (thanks alexander-zubkov)

Changed

• Drop support for Dart SDK versions below 3.0.0
• Refactor unit test suites and improve test coverage
• Switch from pedantic to the official Dart lint rules

Added

• Add UnaryPlus operator (thanks jpnurmi)

Changed

• Improve evaluation of unary minus as an exponent of a power (thanks edhom)
• Use markdown LaTeX instead of images in README (thanks dvirberlo)

Changed

• Evaluate roots written as powers correctly for negative bases (thanks edhom)

Added

• Add factorial function (thanks Just-Learned-It)

Changed

• Switch from Travis CI to GitHub Actions
• Adopt Keep a Changelog format

• Add algorithmic function that is bound to a Dart handler function, including parser support (thanks kamimark)

• Fix inaccuracies in sin/cos/tan when using math.pi (machine pi) (thanks mbullington)

• Bumped to stable release.

• Drop support for Dart SDK versions below 2.12.0
• Migrate to null safety (thanks albertodev01)

• Lower precedence of unary minus below power operator to match common mathematics conventions so that -x^y is parsed as -(x^y) instead of (-x)^y

• Add ability to unbind variable names (by wdavies973)
• Fix parsing of ceil function (by pepsin)

• Drop support for Dart SDK versions below 2.1.1
• Enable unnecessary_new lint rule
• Parser throws FormatException instead of StateError or ArgumentError for invalid input string
• Remove underscore syntax previously supported for unary minus
• Fix toString() parser compatibility for the following expressions:
  • Logarithm function: Change string representation from log_b(x) to log(b, x)
  • N-th root function: Change string representation from nrt_n(x) to nrt(n, x)
  • Exponential function: Change string representation from exp(x) to e(x)

• Package health and maintenance cleanups

• Drop support for Dart SDK versions below 2.0.0
• Add arcsin, arccos, arctan functions
• Fix floor and ceil functions
• Update examples and documentation
• Switch to pedantic analysis options

• Add support for Dart 2.0
• Drop support for Dart SDK versions below 1.24.0
• Depend on vector_math 2.0.0 or newer

• Last release to only support Dart 1.x
• Prepare for Dart 2.0
• Enable strong mode
• Analyzer and linter fixes
• Drop support for Dart SDK versions below 1.21.0

• Rename Point3D to Point3
• Point3 now is a subtype of Vector3
• Add mod (%) operator and ceil, floor functions
• Fixing a few missed chain rules in derive

• Add support for basic vector operations
• Switch to using test instead of unittest package
• Warning: Depends on git version of vector_math as latest pub release is severely outdated

• Depend on vector_math 1.4.4 or greater

• Add absolute value function (by markhats)
• Add sign function
• Improve test coverage
• Adapt string representation of unary minus to standard syntax

• To create exponentials, use e(x) or e^x. Consequently, removed support for exp(x).
• Improve test coverage
• Update dependencies

• Bring back standard syntax for unary minus: -5 works now. (by markhats)
• Add parser support for e^x additional to exp(x). (by markhats)

• Introduce nested context/naming scopes
• Improve vector evaluation
• Add some missing methods
• Improve test coverage (custom and composite functions)
• Remove boilerplate code

• Add compose operator for functions: Use & to conveniently create a CompositeFunction from two existing functions: expr = f & g;
• Improve documentation and dartdoc generation

• Minor code cleanup
• Prepare for Dart 1.0

• Fix handling of operator associativity
• Add support for default functions to parser
• Add support for unary minus to parser: Input with underscore. Instead of 2*-5 use 2*_5.

• Add cli evaluator to examples
• Improve test coverage
• Fix bug in differentiation of Sin and Cos
• Remove support of unary minus in Parser

• Improve test coverage
• Improve documentation
• Fix bug in simplification of Minus
• Fix bug in simplification of Times
• Implement evaluation of nth root

• Initial release of standalone version

• Improve documentation and examples