What does "expression" do?

[couto886]

I'm really sorry if this is a stupid question, but I cant figure what is the difference between using just "call" or "jump" and using "call expression" or "jump expression". The code I'm using as a guide use expression constantly, so I suppose there must be some function, but even reading INCOUNTABLE TIMES in the official guide I just cant figure out what this actually does. I would REALLY apreciate if somebody could help me. Again, sorry if this is a dumb question. I really don't know where to look for anymore.

[PyTom]

So, normally when you do:

Code: Select all

jump foo

It will jump to the label foo. However, there are times where you want to jump to a label that's been stored in a variable. For example, one that's beenm computed. Take something like:

Code: Select all

default day = 0

label day_loop:
     $ day += 1
     "The dawn of day [day]."
     
     $ day_label = "start_day_{}".format(day)
     jump expression day_label

What this does it sot assign to day_label the strings "start_day_1", "start_day_2", and so on. Then the jump expression statement causes control to transfer to the appropriate label.

[couto886]

So the "expression" just allow the variables to be transferred in the jump??

[rames44]

Not “transferred.” “expression” says “I am computing the name of the label you should jump to instead of giving it to you directly.”