How to check if a folder exists and create if not?

[#1]

You are looking for the functions Directory Exists("path") and Create Directory("path"). Something like:

path = "C:\foo\bar";
If(!Directory Exists(path),
     Create Directory(path),
     Print(path||" already exists.")
);

[#2]

Look at function

     Is Directory()

to check to see if a directory exists, and

     Create Directory()

to create a directory

Names Default To Here( 1 );
If( Is Directory( "C:\zippy" ) == 0,
	rc = Create Directory( "CL\zippy" )
);

Examples and definition of these functions are found in

     Help==>Scripting Index