John W. Carr

The use of the Kleene regular expression notation for describing algebraic language syntax, in particular of ALGOL, is described in this paper. A FORTRAN II computer program for carrying out the elimination algorithm of Gorn, similar to Gaussian elimination for linear systems of algebraic equations, is described. This was applied to numerous smaller languages, including some sublanguages of ALGOL. A hand calculation result of the application of the algorithm to all of ALGOL is given, thus expressing the Revised ALGOL 1960 syntax in completely nonrecursive terms, as far as its context-free portion is concerned. This description in many ways is far more intuitively understood than the previous recursive description, it is suggested. The paper also includes results of the machine program, which does not include a simplification algorithm.