Inside Macintosh: AppleScript Language Guide / Part 3 - Appendixes

Appendix A - The Language at a Glance

Handlers

Handlers are collections of statements that are executed in response to commands or error messages. Table A-6 summarizes handler definitions
and subroutine calls.

Handler definitions and calls

Handler	Syntax
Subroutine definition (labeled parameters)	( on | to ) subroutineName ¨ [ of | in directParameterVariable ] ¨ [ subroutineParamLabel paramVariable ] ... ¨ [ given label:paramVariable [, label:paramVariable ]...] [ global variable [, variable ]...] [ local variable [, variable ]...] [ statement ]... end [ subroutineName ]
Subroutine call (labeled parameters)	subroutineName ¨ [ ( of | in ) directParameter ] ¨ [ subroutineParamLabel parameterValue ] ¨ | [ with labelForTrueParam [, labelForTrueParam ]... ¨ [( and | or | , ) labelForTrueParam ] ] ¨ | [ without labelForFalseParam [, labelForFalseParam ]... ¨ [( and | or | , ) labelForFalseParam ] ] ¨ | [ given label:parameterValue ¨ [, label:parameterValue ]...] ] ...
Subroutine definition (positional parameters)	( on | to ) subroutineName ( [ paramVariable [, paramVariable ]...] ) [ global variable [, variable ]...] [ local variable [, variable ]...] [ statement ]... end [ subroutineName ]
Subroutine call (positional parameters)	subroutineName ( [ parameterValue [, parameterValue ]...] )
Return statement	return expression
Command handler definition	( on | to ) commandName ¨ [ [ of ] directParameterVariable ] ¨ [ [ given ] label:paramVariable [, label:paramVariable ]...] [ global variable [, variable ]...] [ local variable [, variable ]...] [ statement ]... end [ commandName ]