Adding End of Block (EOB) Characters

The Add EOB function appends exactly one End of Block character ; at the end of each line of the program, without affecting comments or the code structure. This helps bring the program to a uniform format required by certain CNC controllers and postprocessors.

What the function does

• Processes the file line by line, ignoring completely empty lines.
• Recognizes lines consisting only of comments ( ... ) (possibly with ; at the edges) — such lines do not receive a ; character.
• If a line contains both code and a comment — it first removes extra ; from the code, then adds exactly one ; and returns the comment back in place.
• Normalizes trailing ;: multiple semicolons are reduced to one.

Algorithm (short version)

1. Trim trailing spaces in each line (trimEnd()).
2. If the line is only a comment, return it unchanged (and without outer ;).
3. Extract comments (...) and temporarily remove them from the code.
4. Remove extra ; at the end of the code, then add one ; if the line contains code.
5. Merge the code and comments back together.

Examples

; Before:
N10 G00 X0 Y0 (Rapid move)
N20 G01 X10 Y10 F100;;
(Technological comment);
N30 G03 X20 Y0 I5 J0

; After:
N10 G00 X0 Y0; (Rapid move)
N20 G01 X10 Y10 F100; (Technological comment)
(Technological comment)
N30 G03 X20 Y0 I5 J0;

When to use

• Before exporting/sending the program to a machine where ; is required as EOB.
• To align style after importing from CAM or manual edits.
• After “cleaning” or other formatting to ensure a consistent EOB.