FEM: codeformating, add a file with some information

src/Mod/Fem/CMakeLists.txt

@@ -20,6 +20,7 @@ endif(BUILD_GUI)
 
 # Python non Gui packages and modules
 SET(FemScripts_SRCS
+    codeformating.md
     Init.py
     InitGui.py
     ObjectsFem.py

src/Mod/Fem/codeformating.md

@@ -0,0 +1,35 @@
+# FEM coding rules
+
+## Python and C++
+- All files should have a licence header
+- Unix line endings are preferend
+- never use mixed line endings on one file
+- 4 Spaces for indent
+- no trailing white spaces
+
+## Python
+#### Code formating
+- 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 and file names that are not supposed to be used for scripting should start with underscore like _MyInternalClass
+
+### Python code formating 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 []
+- www.lgtm.com
+- TODO: check pylint
+- automatic code formater will not be used for existant code
+- for new code if someone would like to use a code formater black should be used
+
+## C++
+### Naming policy
+- CamelCase names