ScriptExpression has somewhat unclear / coupled interface. There are m_code, m_codeStr, which are being sometimes protected by mutex, sometimes not. It seems that preCode and postCode are not used at all. Also there are functions like setCode, which instantiate a parser and JSEngine and doing lots of things, sometimes quite non-obvious.

For example logic of updated ScriptExpressions and ScriptExpression::writeOut itself are a bit of a magic.

It would be nice to figure out and simplify the workflow when using them. That requires a bit of time investigating and potentially refactoring.

Otherwise it's quite hard to work in the area and sometimes it's change & pray type of work.

Some more details / context: 
Dmitrii Akshintsev: Hi everyone, I have a somewhat follow-up / related question to… 
posted in Foundation / QML at Feb 5, 3:01:24 PM