Revision as of 13:52, 13 February 2012

EGL provides general statements such as if and while, as well as action statements for accessing data sources and for invoking external logic.

General statements

The general statements are case, continue, exit, for, if, move, return, throw, transfer, try, use, and while.

Case

The case statement responds to conditions at run time by executing one set of statements rather than another:

• You can test a criterion value. The following example invokes mySecondFunction:

function test()
   x Int = 3; 
 
   case (x)
      when (1)
         myFirstFunction();
      when (2, 3, 4)
         mySecondFunction();      
      otherwise
         myDefaultFunction();
   end   
end

• You can test a set of logical expressions. The following example displays only "x passes":

function test()
   x Int = 3;
   y Int = 5;
   z Int = 7;
 
   case
      when (x == 3)
         SysLib.writeStdOut("x passes");
      when (y == 5)
         SysLib.writeStdOut("y passes");
      when (z == 7)
         SysLib.writeStdOut("z passes");
      otherwise
         SysLib.writeStdErr("You will not see this message.");
      end
   end 
end

As shown, no more than one clause ever executes. Control does not “fall through” from one clause to the next.

Continue

Exit

For

If

Move

Return

Throw

Try

Use

While

Action statements

The action statements are add, call, close, delete, execute, forEach, get, open, prepare, and transfer.

Add

Call

Close

Delete

Execute

ForEach

Get

Open

Prepare

Replace

Transfer