param

Type

function

Summary

Returns the specified parameter passed to the current handler.

Syntax

the param of <parameterNumber>

param(<parameterNumber>)

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\".

Parameters

Name	Type	Description
parameterNumber		A non-negative integer.

Examples

param(3) -- returns the third parameter

param(0) -- returns the handler name

Value

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

Related

control structure: function

function: paramCount

glossary: pass, handler, parameter, return

Compatibility and Support

Introduced

LiveCode 1.0

OS

mac

windows

linux

ios

android

Platforms

desktop

server

mobile