Release 0.8.0 "Gabriel" - Symbolic operations, equations and library

This release adds symbolic integration, differentiation and equation solving, delivers an extensive equation library, and improves the library feature to enable large library objects to be defined in separate files and optimize execution speed for library items. It also improves the rendering of complex equations and fixes a number of crashes or user-interface problems.

Features

• Symbolic integration, Primitive command, '∫X(sin(X))' syntax
  '∫X(sin(2*X+3)-X)' evaluates as '-cos(2*X+3)/2-x²/2'
• Symbolic differentiation, Derivative command, ∂X(sin(X)) syntax
  '∂X(sin(2*X+3)-X)' evaluates as '2·cos(2*X+3)-1'
• Symbolic equation resolution, ISOL (Isolate) command
  'sin(2*X+3)=A' 'X' ISOL gives 'X=(sin⁻¹ A+2*i1*π-3)/2'
• Apply arithmetic and functions on both sides of equations like A=B
'A=B' sin 1 + results in 'sin A+1=sin B+1'
• Add possibility to define library objects in separate files
  The various demos from previous releases are now also in the library
• commands: Add →Prog command to convert expressions to RPL programs
  'sin(2*X-Y)' →Prog gives « 2 X × Y - sin »
• Accelerate evaluation of library entries
  Invoking a library object is as fast as if it was on the stack.
  Notice that this is faster than global objects that require lookup.
• Add Obj→ support for user-defined function calls
  'F(A;B;C)' Obj→ DROP Obj→ gives [F A B C].
  The first call to Obj→ expands the expression, leaving an isolated
  function call on the stack, which the second Obj→ expands.
• Automatically convert polynomial objects to expressions when needed
• Many improvements to the equation library contributed by Jean Wilson
• Document the equation library variables in the help file
• Add classical/relativistic Kinetic Energy comparison demo
  This was suggested by Jean Wilson as an illustration
• parser: Parse and convert HP syntax for |
  Typing 'A(X;Y)|(X=1;Y=2)' converts to 'A(X;Y)|X=1|Y=2'

Bug fixes

• Improve graphical rendering of some complex expressions
• Render sqrt as √ and not squareroot in HP compatibility mode
• Do not draw parentheses around |x| when rendering abs
• Redefine rpm as turn/min (unit consistency of rotational speed)
• Avoid crash in for loop if termination condition fails to evaluate
• Fix rendering and saving of directories
• Do not leave incorrect stack content when running Obj→ on text
• Make size consistent in vectors containing tagged objects
• Accept tagged objects as input in algebraic functions
• Avoid parsing error for 1,234 when . is the decimal separator
• Debug output related to expressions is no longer labelled "equations"
• Fix unit error in Drift Speed & Current Density
• Cut the size of the build version ID to avoid DMCP buffer overflows
• Avoid possible corruption when an error occurs in a program
• Improve error messages for file errors, e.g. when loading a state
• Move cursor at correct position after numbers when entering units
• Reject multiple consecutive units, e.g. 1_m_s
• Fix issue where we insert = incorrectly on the command line
• Address simulator warning about potential buffer overflow

Improvements

• tests: Add tests for the newly added library entries
• primitive: Add test suite for symbolic integration
• tests: Add test suite for symbolic differentiation
• Factor out code to expand objects on the stack
• make install now Installs from distribution files
• demo: Reorganize demo files as directories
• tests: Add test for Obj→ on various object types
• tests: Factor out code checking state of the complete stack
• tests: Avoid emitting something that looks like compilation errors
• Update demo file
• Improve definition of atomic mass unit, add Da (Dalton) alias
• expressions: Optimize the way to split an equation
• tests: Adjust tests after changes in SymbolicMenu

Full Changelog: v0.7.18...v0.8.0