# Pastebin GBpMKW0A
( Checks to see if an ascii character code is a digit )
( chr -- true | false )
: LOOKS-LIKE-DIGIT
  ( Assuming we're working with ASCII and not something like EBCDIC, it should be safe to assume that numbers fall between 48: 0, and 57: 9. )
  DUP 48 >= SWAP 57 <= -1 = =
;

( Checks to see if a string looks like a number )
( addr len -- true | false )
: LOOKS-LIKE-NUMBER
  -1 SWAP 0 DO
    DROP                            ( Discard until last iteration )
    DUP C@                          ( Save address, fetch character )
      LOOKS-LIKE-DIGIT INVERT IF    ( Check to ensure this is a digit in ASCII )
        0 LEAVE                     ( gtfo )
      THEN                          ( Not a digit )
  1+ -1 LOOP                        ( Might be a number )
  SWAP DROP -1 =
;