Pep and Nom

the peep register in the ℙ𝕖𝕡 engine

The peep buffer is a single character buffer which stores the next character in the input stream. When a read command is performed the current value of the peep buffer is appended to the workspace buffer and the next character from the input stream is placed into the peep buffer.

The “end-of-stream” tests <eof> <EOF> (eof) (EOF) check to see if the peep buffer contains the end of input stream marker.

The while command reads from the input stream while the peep buffer is, or is not, some set of characters

 while [abc];

The code below is implicitly using the peep register in the while and whilenot commands

    while [:space:]; clear;
    whilenot [:space:]; put; clear; add "word*"; push; 
   parse>
    pop; pop; 
    # print one word per line
    # grammar rules 
    #   text := ( word word ) | ( text word ) ;
    "word*word*","text*word*" {
      clear; get; add "\n"; ++; get; --; put;
      clear; add "text*"; 
      push; .reparse
    }
    push; push;
    (eof) { pop; clear; get; print; quit; }
  

see also

read , while , whilenot