Where does values of argument `timestamp` of quantstrat::ruleSignal's come from?

Question

When reading source code of ruleSignal, argument timestamp at line 66 is a very important input, but I could not figure out where timestamp data come from.

It seems that functions add.indicator, add.signal, add.rule, applyIndicators, applySignals, which run before ruleSignal don't use or generate timestamps values.

I wonder which function generates values of timestamp for ruleSignal to use, or where data of timestamp come from.

Thanks a lot!

Answer 1

Thanks to Brian Peterson's reply which answers my question:

indicators and signals are always presumed to be vectorized, per the documentation, so no timestamp is required.

rules, by default, are path dependent, and thus need a timestamp to operate from.

The path-dependent loop is outside of the individual rule function. see line 555 of rules.R