RFC 83 (rfc83) - Page 2 of 13

Language-machine for data reconfiguration

RFC 83                 Language Machine For Data        18 December 1970


      Step 1:  R1 is made the current rule.

      Step 2:  The current rule is applied to the input data.

      Step3:   a) If the rule fails, the rule of priority one lower is
                  made current.

               b) If the rule succeeds, the rule of highest priority is
                  made current

               c) When the rule of lowest priority fails, the form fails
                  and application of the form to the input data
                  terminates.

      Step 4:  Continue at Step 2.

   In addition, during Step 2, if the remainder of the input string is
   insufficient to satisfy a rule, then that rule fails and partial
   results are not emitted.  If a rule fills the output string,
   application of the form is terminated.

II.  Rules

   A rule is a replacement operation of the form:

      left-hand-side -> right-hand-side

   Both sides of a rule consists of a series of zero or more _terms_
   (see below) separated by commas.

   The left-hand-side of the rule is applied to the input string at the
   current position as a pattern-match operation.  If it exactly
   describes the input, 1) the current input position pointer is
   advanced over the matched input, 2) the right-hand-side emits data at
   the current position in the output string, and 3) the current output
   position pointer is advanced over the emitted data.

III.  Terms

   A term is a variable that describes the input string to be matched or
   the output string to be emitted.  A term has three formats.










Anderson, et. al.