FSI constant

String const FSI = '\u2068'

U+2068 FIRST STRONG ISOLATE

Treat the following text as isolated and in the direction of its first strong directional character that is not inside a nested isolate.

This essentially "autodetects" the directionality of the text. It is not 100% reliable. For example, Arabic text that starts with an English quote will be detected as LTR, not RTL, which will lead to the text being in a weird order.

Use PDI to end the isolated scope.

Implementation 

static const String FSI = '\u2068'