What is the point of "bis_fnc_param"?

[SRBuckey5266 3]

Is it supposed to be a replacement for "_this select 0"?

Are there any differences in speed?

[Sniperwolf572 759]

_this select 0 will always be faster due to the fact it's not doing anything else besides getting the 0 indexed element from _this.

However BIS_fnc_param has advantages to make your life easier:

• Default values - Value to be used if a parameter is not defined. Useful for certain defaults and optional parameters.
  
• Type checking - Requiring a parameter to be of a certain type(s). In case you need an object but someone passes in an int or a string, an error is shown.
  
• Array length checking - If the parameter can take an array, check that it has a required amount of elements.
  

This way, you don't need to write code for these things yourself. More info here and here.

Edited July 22, 2014 by Sniperwolf572

[Grumpy Old Man 3550]

Like sniperwolf573 said, it's to make your life easier.

A good quote the wiki says "If you need to write it twice put it in a function".

[moricky 211]

More info can be found on Community Wiki:

BIS_fnc_param

Functions Library

EDIT: Nevermind, just noticed that Sniperwolf572 mentioned them already :)

[fight9 14]

I find the functions makes setting default values for optional arguments easier.

_param0 = if (count _this > 0) then {_this select 0} else {false};

// is the same as 

_param0 = [_this,0,false] call BIS_fnc_param;