ℙ𝕖𝕡 🙴 ℕ𝕠𝕞

In America people drive on the right side of the road, in England they drive on the left. In India, it is optional. The guru

negation in the ℕ𝕠𝕞 language

About the nom negation operator !

The nom language uses the fairly standard bang operator “!” as a negation operator. This can be put before all types of tests , such as class tests (eg [:space:] ), text-is tests (eg “abc"), begins-with tests (eg:” B"abc") ends-with tests (eg: E"abc") etc.

   read; 
   [:space:] { clear; .restart }
   [:alnum:] { 
     while [:alnum:]; put; 
     clear; add "word*"; push; .reparse
   }
  parse>
   !"" { 
     put; clear;
     add "! Incorrect character '"; get; add "'\n";
     add "! (only alpha-numeric allowed) \n"; 
     print; quit;
   }
 

notes

In the unix text-stream editor, SED the negation operator goes after the test it is modifying, but in ℕ𝕠𝕞 the negation operator goes before.

The idiom below !"" {...} is a simple way to determine if there is a character or characters in the input-steam which is acceptable in the current language. This snippet normal goes just before the parse> label after all other characters and strings have been tokenised.

   !"" { 
     put; clear;
     add "! Incorrect character '"; get; add "'\n";
     print; quit;
   }
  

Double negation (!!) is not permitted because it is fairly semantically useless (no?), and the same applies to triple, quadruple etc negation.

see also

• tests which are the tests which precede nom block sections.
• classes which can be negated by the “!” operator when they are used as tests (not as an argument to the while and whilenot commands