Pep and Nom

the ℕ𝕠𝕞 "quit" command

This command immediately exits out of the nom script without processing any more script commands or input stream characters. The command takes no parameters.

This comand is often used when some kind of format or syntax error is detected in the input or it is used at the end of the input-stream.

exit the script if a 'bad' character is found



    read; 
    [:alnum:],[:space:] { print; clear; }
    !"" {
      put; clear;
      add "! strange character found '"; get; add "'\n";
      add "  sampai jumpa lagi...\n"; print;
      quit;
    }

The idiom above of handling different character classes and then clearing the workspace buffer. Then we can use the workspace not empty" text ( !""* ) to check for characters that should not be in the input-stream for whatever format that ℕ𝕠𝕞 is parsing or transforming.

using quit with incorrect parse-token syntax.



    "parameter*parameter*" {
      clear; 
      add "! Error in input at line "; lines;
      add "! character "; chars; add "\n";
      add " (Multiple parameters are not allowed in 'Gurgle')";
      print; 
      quit;
    }

notes

This command is similar to the SED command 'q'

It would be useful for this command to provide an exit (or error) code. eg “quit 1;” But it doesn't currently (feb 2025).

The nom commands while , whilenot and until do not automatically exit when the EOF marker is encountered in the input-stream. So, in this case an explicit quit command must be used.

The read command will automatically (and 'silently') exit the script when the end-of-stream is encountered. This is what it is supposed to do, but sometimes it is surprising and mysterious.