param

Typefunction
DictionaryLCS
LibraryLiveCode Script
Syntax
the param of <parameterNumber>
param(<parameterNumber>)
Summary

Returns the specified parameter passed to the current handler.

Introduced1.0
OSmac, windows, linux, ios, android
Platformsdesktop, server, mobile
Parameters
NameTypeDescription
parameterNumber

A non-negative integer.

Example
param(3) -- returns the third parameter
param(0) -- returns the handler name
Values
NameTypeDescription
return

The param function returns the parameter value specified by the parameterNumber. If the parameterNumber is zero, the param function returns the handler name.

RelatedControl Structure: function
Glossary: pass, handler, parameter, return
Function: paramCount
Description

Use the param function within a handler to get the value of a parameter when you don't know in advance how many parameters will be passed to the handler.

Usually, you assign names to parameters in the first line of a function handler or message handler. For example, the following function assigns three parameters, which are multiplied together:

function product firstFactor,secondFactor,thirdFactor
    return firstFactor * secondFactor * thirdFactor
end product

But if you want to multiply all the numbers passed to the function handler together, you don't know ahead of time how many parameters will be passed, so you can't assign a parameter name (such as firstFactor) to each one in the first line of the function handler. In this case, you can use the param function to use each parameter without needing to assign it a name:

function product
    put 1 into total
    repeat with nextFactor = 1 to the paramCount
        multiply total by param(nextFactor)
    end repeat
    return total
end product

LiveCode evaluates the parameters before passing them. So if you call myHandler with the following statement:

 myHandler 1+1,"A","Hello" && "world" 

the parameters returned by the param function are

2, A, and "Hello World".

Tagsproperties