AppleScript in a Nutshell

Flow-Control Statements

AppleScript includes syntax that you can use to test expressions and only have some code execute if certain conditions are met, as well as loop through code statements and then exit from the loop. These programming constructs are often called flow-control statements. These statements are covered extensively in Chapter 7.

Like many other programming languages, AppleScript uses an if...then...else...end if statement to test various expressions. AppleScript also has an if simple statement and an if compound statement (one that extends over several lines). For example, you can use code such as:

if numVar > 1000 then return 1000

on one line without including any end ifs. Example 1-13 includes both types of if statements.

AppleScript uses several variations of the repeat statement to loop through code (see Example 1-13). Repeat is AppleScript’s version of the for (;;;) or while... or foreach... loops of other languages like Perl or Java. AppleScripters often use repeat to loop through the values of a list. For example, the code:

repeat with m in listVar...end repeat

will loop through all of the list members stored in the variable listVar. Within the loop, the iterator variable m will sequentially contain each list-member value. Example 1-13 includes several versions of the repeat and if...end if statements.

Example 1-13. AppleScript if and repeat Statements

set userNum to 75.66 (* compound if statement *) if the class of userNum is real then display dialog "It's ...