What is eval, and how i can use?

[mephisto]

Well, that's my question, I've seen in a lot of scripts, but I never figured what do, and for what?..

And how I can use this?
__-

And the other question, I see in several scripts a method or whatever that puts 'include', just below the script header:

Class Game_Maker

 

include something

Those are my question of the day.

 

[LegacyCrono]

Okay, first the include.
This will add to the current scope (class/module/program) the existing procedures on the specified module. So let's say...
[rgss]class Person
  include Communication
[/rgss]
This will add to Person all the functions from Communication. So if there's a def talk at Communication, Person will be able to use it as well.

eval is a bit difficult to explain. When you're coding, at the Script editor, you might need to execute dynamic codes. You can create a String that holds a code piece and execute it using eval.
[rgss]# This will change the Switch 1 to false
codeA = "$game_switches[1] = false"
eval(codeA)
 
# This will return true whenever the condition is met
case @index
when 0
  @condition = "true"
when 1
  @condition = "$game_party.actors.size > 0"
when 2
  @condition = "$game_party.gold > 0"
end
codeB = "return true if " + @condition
result = eval(codeB)
[/rgss]

Eval is specially used for "Execute script" on events. At the Event editor, you'll type a RGSS code that's kept on a String. When the Event is run, this String is executed using eval.


SEE YA!!!!!