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 ]