Test for variable substitution

Click "Refersh" to refresh the card, and the varaible references in the card will be substitued

set hi = "hello", name = " Yi chao"
=> $(hi),$name
=> $hi,$(name:escape)
=> $hi,$(name:e)
=> $hi,$(name:u)

set name2 = $$(name:e)
=> $(hi),$(name2)
=> $(hi),$$(name:e)

set name3 = $$(name2:u)
=> $(hi),$name3
=> $(hi),$(name3:e)