Functions and variables in ladder

This test case it part of the test suite proposed for new devices.

Test case ID: R0257
Language: ST,LD

Code:

tests2/t0257a.fbd
    <vars name="W" datatype="INT"/>
    <vars name="X1" datatype="INT" init="10"/>
    <vars name="Y1" datatype="INT" init="3"/>
    <vars name="Z" datatype="INT"/>
 (* graphical code omitted in this listing *)

tests2/t0257b.st
// used by functionAndVars.ld
FUNCTION SUB2 : INT
  VAR_INPUT
    IN1: INT;
    IN2: INT;
  END_VAR
    SUB2 := IN1-IN2;

END_FUNCTION