Combining ALGOL statement analysis with validity checking
The article by Robert W. Floyd in the March 1960 issue described an algorithm for determining whether a given symbol string is a permissible ALGOL assignment statement. In his method Mr. Floyd replaces certain character pairs by single characters in an array until, in the well-formed formula, the character &Sgr; is obtained. Although this method indeed determines formation legality, one must still analyze and delimit each constituent of the statement in order to reduce the problem language to a workable format.