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function

function functionName [parameterList]
  statements
end functionName

The function keyword defines a new function handler of the specified name. You call a function by placing parentheses after its name, enclosing any parameters within the parentheses:

get deleteSpaces(" hello ")

The optional parameterList lets a function handler receive values sent along with the function call.

When a function is called, HyperCard evaluates each item within the parenthetical list following the function's name. When the handler begins to execute, HyperCard assigns each value to a parameter variable in the parameterList.

Use the return keyword within the function definition to have the function return a value to the handler that called it. If you don't use return, the function evaluates to empty.

Demo Script

on mouseUp
   ask "What is your name?"
   if it is empty then exit mouseUp
   answer "Your name spelled backwards is" && reverseString(it) & "."
 end mouseUp
 

 function reverseString theString
   repeat with i = the number of chars in theString down to 1
     put char i of theString after theReversedString
   end repeat
   return theReversedString
 end reverseString

Placeholders

myAverage
onlyOneWindow

function myAverage theNumbers
function onlyOneWindow

var1
var1,var2,var3, var4
fieldName, N, numberOfCharacters

put "Hello world"   -- built-in command
get total(field 1)  -- function call
global HelpInfo     -- keyword

Related Topics

• exit
• param
• paramCount
• params
• return
• The message-passing order
• Using parameter variables
• Writing function handlers