difference between function and command and sending parameters

[Eric Chatonet]

Bonjour William,

Le 17 oct. 08 à 17:08, william humphrey a écrit :

> 2. why would anyone use the function thing when they can use a  
> command with
> a parameter. What good is a function? I guess when you want multiple
> parameters?

Functions are useful and handy because their main purpose is to  
return a value:

set the enabled of group "Commands" to ThereIsAPilot() --

function ThereIsAPilot
   return "William" is among the lines of CurrentUsers() --
   -- returned value will be a Boolean (TrueOrFalse)
end ThereIsAPilot

function CurrentUsers
   return fld "Users" of card "Reference"
   -- returned value will be a list of lines
end CurrentUsers

Etc.

Consider this just to understand how it works.
Actually commands can return a value also (using the result... that  
is actually a function :-) but it's less handy.

More generally, think about commands (on, command) when this will  
lead to a result visible by the user in your GUI.
And think about functions to get values you need to achieve a process.

There would be hundred of pages to write about commands versus  
functions: see the user guide p. 121 and after.

About F and H used in Rev 3.x script editor in lists, I assume that H  
means 'handler' and could be considered as incorrect since a function  
is a handler as commands are :-)
And, after having verified, Rev docs name commands handlers...

Best regards from Paris,
Eric Chatonet.
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