Correctly identify errors when parsing erroneous code (make sure flex goes back to INITIAL state when code contains errors that do not allow determining whether ST or IL is being parsed)
(* Following taken directly from the IEC 61131.3 draft standard *)
(*
* An IEC 61131-3 IL and ST compiler.
*
* Based on the
* FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
*
*)
(*
* This is part of the library conatining the functions
* and function blocks defined in the standard.
*
* Edge detection function blocks
* ------------------------------
*)
FUNCTION_BLOCK R_TRIG
VAR_INPUT CLK: BOOL; END_VAR
VAR_OUTPUT Q: BOOL; END_VAR
VAR RETAIN M: BOOL; END_VAR
Q := CLK AND NOT M;
M := CLK;
END_FUNCTION_BLOCK
FUNCTION_BLOCK F_TRIG
VAR_INPUT CLK: BOOL; END_VAR
VAR_OUTPUT Q: BOOL; END_VAR
VAR RETAIN M: BOOL; END_VAR
Q := NOT CLK AND NOT M;
M := NOT CLK;
END_FUNCTION_BLOCK