Revision as of 14:09, 13 February 2012

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

General statements

The general statements are case, continue, exit, for, if, move, return, throw, 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

The EGL continue statement returns control to the start of a block of code controlled by a for, forEach, or while statement. The statement lets you return to a labeled statement of one of those kinds, or to the nearest embedding statement of one of those kinds.

The following example assumes that you have coded a print function named printReport.

for (i from 1 to 100 by 1)
 
   printReport(myList[i]);
 
   if ((i % 10) != 0)
      continue;
   end // if
 
   printReport(blankLine);
end // for

That code prints the members of a list, inserting a blank line between each group of ten.

Exit

The EGL exit statement exits from a function, program, service, or run unit or from a block of code controlled by a case, for, forEach, if, or while statement.

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