function_tree

• Added the ability to create symbolic derivatives from single variable functions where they are well defined. Early versions had numeric differentiation (and integration), but these were removed in later versions as not being part of the focused use case. (I'm not sure whether symbolic derivatives will stay either — they're still experimental.) These can be accessed through the methods SingleVariableFunction.derivative and MultiVariableFunction.partial. The resulting trees are often unnecessarily large for now; tree pruning to come if the trees are to stay!

• Incorporated Dart 3 features.
• More resilient to repeated negation / confirmation.
• Added a representation method on trees to show structure.
• Added a toString representation of nodes and function trees.
• Cleaned up the code base to be easier to read and to better match the dart.dev recommendations.
• Interpreter shakes out some unnecessary components, such as parentheses surrounding constants, while generating tree.

• Allow unary + or - to directly follow the *, /, ^ or % operators.

• Parse numbers as doubles instead of nums to prevents common use case issues with large integers.

• Oh dear! This time with debug mode off!

• Fixed unary sign bug that treated expressions like -a+b as -(a+b). Wow!

• Added null safety!
• String interpolation appears even slower than before, but the generated function trees are still pretty efficient (once generated, within an order of magnitude of native Dart math library functions).

• Added functionality for two-parameter functions, log, nrt and pow in response to a feature request.

• Important bug fix: differences

• Dusted out some cobwebs.
• Renamed FunctionTree MultiVariableFunction and FunctionOfX SingleVariableFunction, which is more expressive.
• Removed zero, derivative and integral estimates, which I feel were tangential.

Fixed ambiguity issue: if the user chooses a variable name in an expression that happens to be a special constant name (such as 'e'), the parser will take occurrences in the expression to mean that the variable.

• Marked as ready for Dart 2.
• dartfmt-ed some of the files.
• Added support for the % operator.
• Added support for floor, ceil and round.
• Added come timing comparisons between evaluating native Dart functions, function tree instances and repeated string parsing in test/.

• Re-wrote the parsing engine: code much cleaner and easier to read.
• Cleared out deprecated dart:math constants.
• Updated code for Dart 2.
• Added support for abs.

• Basic numerical differentiation.
• Basic numerical integration (Simpson).
• Basic zero-finding (Newton).
• Very much proof of concept.

• Initial version, proof of concept.
• Very little checking of input at this stage.