Pep and Nom

the ℕ𝕠𝕞 "clear" command

clear or delete the text in the workspace buffer.

A very common procedure in a nom script when parsing and translating a formal language (examples of languages are the json text data format, the “java” programming language, or the set of palindromes is to 1^st match a set of parse tokens, then build the text attribute for the parse token which will replace the matched tokens, and then put the new attribute into the current tape cell. Then clear the workspace buffer and create the new parse token. The example below (from a fictitious grammar for parsing arithmetic expressions) illustrates these steps:

   pop; pop; pop;
   # match the token sequence 'leftbrace expression rightbrace'
   "leftbrace*expression*rightbrace*" {
     clear; 
     # build the new 'attribute' from each parse token attribute
     get; ++; get; ++; get;
     # realign the tape pointer and save the new attribute
     --; --; put; 
     # clear the workspace, build the new parse token, and push on stack
     clear; add "expression*"; push;
     # jump back to the 'parse>' label: this allows any other 
     # grammar reductions/productions to take place
     .reparse
   }
 

The script above represent a single grammar rule or production namely

 expression = leftbrace expression rightbrace ;

the current parse token