On the Most Recent Property of Algol-Like Programs

The paper is concerned with the most recent property of ALGOL-like programs, which has been discussed by Wegner and McGowan([6],[6])and dates back to Dijkstra [l]. A program has the most recent property if at run time the static chain pointer of a procedure φ always points to the most recent, not yet completed, activation of that procedure ψ which lexicographically encloses φ. A run time system cannot apply this most recent strategy for alle programs of a programming language; examples are given for BL in [5],p. 196, and for ALGOL 60 in [2], p. 108. In a main theorem McGowan gives sufficient compile time decidable conditions for the most recent correctness of a BL-program [S].