The usage scenario fits my needs, that is the reason to evaluate exactly this
I mean - should the QScriptEngine be deprecated, the QQmlEngine/QJSEngine
should also have ways to utilize some form of JIT/preparse. Even in the first
pass where JIT cannot be effective (or when I parse just the text expression)
QScriptEngine beats newer and more shiny QJSEngine a lot. That is confusing to
me and my point - why is QJSEngine offered as replacement of QScriptEngine when
it is so much slower?
QJSEngine does not cache the compilation results if you just pass in plain
strings. I also don't think QScriptEngine can do this here (but I haven't
checked). QScriptEngine might be clever enough to automatically use the
interpreter rather than JIT-compiling such small expressions. You can set the
QV4_FORCE_INTERPRETER environment variable to force QJSEngine to use the
interpreter rather than the JIT.
In any case it's a waste to parse the expressions from strings over and over
and to not use the JIT. If you care about performance, you should try to parse
the expressions only once.
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