The following two statements are used for the same condition:

if...then
end if

If...then

In AppleScript, if the statement is just one line, you can type it on a single line rather than in a block, and omit the end if. Compare the following examples:

if x = 3 then
	set y to 4
end if

if x = 3 then set y to 4

Similarly, the following AppleScript statement is the same as that used for the same condition in VBA:

if...
else if...
else if...
else if... 
end if

There is no Select Case statement, so you use this if / else if construction instead.

The equivalent of the VBA with / end with statement in AppleScript is the tell / end tell statement targeted at an application object, as shown in the following example:

tell application "Microsoft Word"
	set textObject to the text object of active document
	tell (get find object of textObject)
		set forward to true
		set wrap to find continue
		set format to false
		set match all word forms to false
		set match case to false
		set match sounds like to false
		set match whole word to false
		set match wildcards to false
		clear formatting
		clear all fuzzy options
		clear formatting (its replacement)
	end tell
end tell

The code below illustrates the standard method for setting options in VBA. You use a with / end with block. The following example uses the Find object in Microsoft Word:

With ActiveDocument.Range.Find
End With

However, in AppleScript, you can go a step further to condense the script by using a list and a tell block to set multiple properties. The following example uses the find object:

tell (get find object of textObject)
	set {forward, wrap, format, match all word forms,¬
		match case, match sounds like, match whole word,¬
		match wildcards} to {true, find continue, false,¬ 
		false, false, false, false, false}
	clear formatting
	clear all fuzzy options
	clear formatting (its replacement)
end tell

You cannot use of to set multiple properties; however, you can access them in a list using get and of, as shown in the following example:

get {forward, wrap, format, match all word forms,¬
	match case, match sounds like, match whole word,¬
	match wildcards} ¬
	of find object of text object of active document

The equivalent of VBA's Do / Loop and For / Next loops in AppleScript is the repeat / end repeat block. There are five types.

Most commonly, in place of VBA's For Each / Next loops, you will use the following AppleScript:

repeat with eachItem in aList
-- code here
end repeat

This construction works when eachItem is an application object reference. When eachItem is a reference that has not yet been evaluated, this construction doesn't work. The = equality operator behaves unexpectedly, as shown in the following example:

repeat with eachItem in {1,2, 3, 4, 5}
	if eachItem = 2 then
		beep
		display dialog (eachItem as string)
		exit repeat
	end if
end repeat
display dialog (eachItem as string)

The result of this code is that no beep is heard, and the dialog displays 5. That's because eachItem never equals 2. It equals item 2 of {1,2,3,4,5}. You can solve this problem by replacing the second line with the following code:

if contents of eachItem = 2 then

You can also solve it using strategies that force an evaluation of eachItem, such as coercion. However, it is simpler to use the following construction:

repeat with i from 1 to (count {1, 2, 3, 4, 5})
	set eachItem to item i of {1, 2, 3, 4, 5}
	if eachItem = 2 then

This construction creates a For / Next loop in all cases.

There is an important difference between VBA and AppleScript when using these loops. The For / Next loop in VBA looks like the following example:

For i = 1 to 5...
Next i

When you exit the loop after five loops, the value of i is 6. However, in AppleScript, the value of i is 5 when you exit the following loop:

repeat with i from 1 to 5

This result will surprise VBA coders who rely on reading the value of n to see whether a loop was exited normally, or by means of an Exit For statement. In AppleScript, exit repeat is the equivalent of Exit For, and gets you out of the block.

There is a construction in AppleScript that is similar to the On Error construction in VBA. You must frame the section of code in which you want to trap the error with a try / end try block, as shown in the following example:

try
--code here
end try

This code is like using an On Error Go To line after end try for any runtime error that occurs within the block.

The following code provides an alternative construction in the event of an error for which you use On Error Resume Next in VBA, but it can be located anywhere in your script:

try
--code here
on error
--alternate code here   
end try

The following more elaborate construction lets you branch depending on what the specific error number or message is:

try
--code here
on error errMsg number errNum
	if errNum = -1708 then
		--alternate code here quoting or parsing 
		--the message and/or checking for the 
		--error number
	else
		-- do something else
	end if
end try

To quit the top level of a script, you can use return at any time. In a subroutine, that will get you back to the main script after the line that called the subroutine. To quit the whole script, even from a subroutine, use the following code:

error number -128

This construction is the same as using the Cancel button. Be sure you're not in a try block at the time. If you are in a try block, you have to test for the error number, and if it is -128, you then invoke error number -128 a second time in the on error section.