create/src/Mod/Fem/coding_conventions.md

FEM coding_conventions

• These coding rules apply to FEM module code only. Other modules or the base system may use different coding rules especially in naming policy of Python.

Spelling

• Be mindful of spelling. Spell checks are quite often neglected.
• [codespell]((https://github.com/codespell-project/codespell#updating) could be used

codespell -q 2 -S *.ts  -L childs,dof,dum,methode,nd,normaly,uint,vertexes,freez  src/Mod/Fem/

Python and C++

Code formatting

• All files should have a license header
• Unix line endings are preferred
• never use mixed line endings on one file
• 4 Spaces for indent
• no trailing white spaces

Python

Code formatting

• except W503 all Python code is pep8 compliant
• maximal line length is 100
• double quotes as string identifier
• One import per line, no * imports allowed as it makes harder to validate code
• the import of FreeCADGui should be guarded by a 'if FreeCAD.GuiUp:'

Naming policy

• snake_case_names
• ClassNames, variable_names_without_capitals and CONSTANTS_USE_CAPITALS, functions_without_capitals
• Function expected to return a value should indicate what is expected, so is_mesh_valid is a good name, but check_mesh is not a good name
• Class names, methode names and variable that are locally and not supposed to be used for scripting should start with underscore like _MyInternalClass

Python code formatting tools

• flake8
  • in source code directory on Linux shell

find src/Mod/Fem/ -name "*\.py" | grep -v InitGui.py | xargs -I [] flake8 --ignore=E266,W503 --max-line-length=100 []

• LGTM
• TODO: check pylint
• automatic code formatter will not be used for existent code
• for new code if someone would like to use a code formatter black should be used

Coding

• print() vs. FreeCAD.Console.PrintMessage()
  • FreeCAD.Console.PrintMessage() or Log or Error should be used
  • print() should be used for debugging only
  • forum topic https://forum.freecadweb.org/viewtopic.php?f=10&t=39110
  • BTW: Console prints need a new line where as print does not need one

Documenting

• Python style is preferred over Doxygen style
  • see ccx tools module in fem tools package
  • see forum topic: https://forum.freecadweb.org/viewtopic.php?f=10&t=37094

C++

Naming policy

• CamelCase names