When you use Symbol() in your trading functions rather than an absolute name, those functions will apply to the current chart pair.
When you use Period() in your trading functions rather than an absolute number, those functions will apply to the current chart period.
Go to a different chart with a different pair and/or period and your trading functions automatically use the new pair symbol and period. Easy. It makes it possible to change things by simply switching charts, rather than editing the EA.
Is there any similar way of specifying by index or other means, an indicator, particularly a custom indicator, that is inserted in the chart? So that it's name doesn't have to be declared/changed in the EA? Like referencing it by GETting it's name or by it's order in the chart or other means?
I haven't found anything like that yet in the documentation yet, but I thought I'd ask.