Labels & Control Flow link
Label Statement link
Label statements allow the given name to be assigned to a program point. They exist solely to be called or jumped to, either from Ren’Py script, Python functions, or from screens.
label sample1:
"Here is 'sample1' label."
label sample2(a="default"):
"Here is 'sample2' label."
"a = [a]"
A label statement may have a block associated with it. In that case, control enters the block whenever the label statement is reached, and proceeds with the statement after the label statement whenever the end of the block is reached.
There are two kinds of labels: global and local labels. Global labels live
in one global scope shared across all project files and thus should have unique
names per game. Local labels logically reside inside the scope of the global label
they are declared in. To declare a local label, prefix its name with a period .
.
For example:
label global_label:
"Inside a global label.."
label .local_name:
"..resides a local one."
jump .local_name
Local labels can be referenced directly inside the same global label they are declared in or by their full name, consisting of global and local name parts:
label another_global:
"Now lets jump inside local label located somewhere else."
jump global_label.local_name
The label statement may take an optional list of parameters. These parameters are processed as described in PEP 570, with two exceptions:
The values of default parameters are evaluated at call time.
The variables are dynamically, rather than lexically, scoped.
When a variable is dynamically scoped, its value lasts until a return statement following the label. It doesn’t generally make sense to have a label with parameters that is reached by a jump or a previous statement. For an example of labels with parameters, see the call statement.
Jump Statement link
The jump statement is used to transfer control to the given label.
If the expression
keyword is present, the expression following it is
evaluated, and the string so computed is used as the label name of the
statement to jump to. If the expression
keyword is not present, the label
name of the statement to jump to must be explicitly given.
Unlike call, jump does not push the next statement onto a stack. As a result, there’s no way to return to where you’ve jumped from.
label loop_start:
e "Oh no! It looks like we're trapped in an infinite loop."
jump loop_start
Call Statement link
The call statement is used to transfer control to the given label. It also pushes the next statement onto the call stack, allowing the return statement to return control to the statement following the call.
If the expression
keyword is present, the expression following it is evaluated, and the
string so computed is used as the name of the label to call. If the
expression
keyword is not present, the name of the statement to call must be
explicitly given.
If the optional from
clause is present, it has the effect of including a label
statement with the given name as the statement immediately following the call
statement. An explicit label helps to ensure that saved games with return
stacks can return to the proper place when loaded on a changed script.
label start:
e "First, we will call a subroutine."
call subroutine
call subroutine(2)
call expression "sub" + "routine" pass (count=3)
return
# ...
label subroutine(count=1):
e "I came here [count] time(s)."
e "Next, we will return from the subroutine."
return
The call statement may take arguments, which are processed as described in PEP 448.
When using a call expression with an arguments list, the pass
keyword must
be inserted between the expression and the arguments list. Otherwise, the
arguments list will be parsed as part of the expression, not as part of the
call.
Return Statement link
The return
statement pops the top statement off of the call stack, and transfers
control to it. If the call stack is empty, the return statement restarts
Ren’Py, returning control to the main menu.
If the optional expression is given to return, it is evaluated, and it’s result
is stored in the _return
variable. This variable is dynamically scoped to each
context.
Special Labels link
The following labels are used by Ren’Py:
start
By default, Ren’Py jumps to this label when the game starts.
quit
If it exists, this label is called in a new context when the user quits the game.
after_load
If it exists, this label is called when a game is loaded. It can be use to fix data when the game is updated. If data is changed by this label,
renpy.block_rollback()
should be called to prevent those changes from being reverted inf the player rolls back past the load point.splashscreen
If it exists, this label is called when the game is first run, before showing the main menu. Please see Adding a Splashscreen.
before_main_menu
If it exists, this label is called before the main menu. It is used in rare cases to set up the main menu, for example by starting a movie playing in the background.
main_menu
If it exists, this label is called instead of the main menu. If it returns, Ren’Py will start the game at the
start
label. For example, the following will immediately start the game without displaying the main menu.label main_menu: return
after_warp
If it is existed, this label is called after a warp but before the warped-to statement executes. Please see Warping to a line.
hide_windows
If it exists, this label is called when the player hides the windows with the right mouse button or the H key. If this returns true, the hide is cancelled (it’s assumed the hide has occurred). Otherwise, the hide continues.