ALGOL W

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Algol-W is a programming language. It was Niklaus Wirth's proposal for a successor to ALGOL 60 in the ALGOL 68 committee.

Algol-W is clearly a transitionary stage between ALGOL 60 and Pascal (created later by Wirth also). It represented a relatively conservative modification of ALGOL 60; Wirth added string, bitstring, complex number and reference to record datatypes and call-by-result passing of parameters, but changed little else.

Like the rest of Wirth's languages (Pascal, Modula-2, Oberon, etc.), Algol-W is small and statically typed. The language that eventually became ALGOL 68 is much larger and more complex than Algol-W, and it differs more from Algol 60 than Algol-W does.

[edit] Code Sample

record PERSON (
    string NAME; 
    integer AGE; 
    logical MALE; 
    reference(PERSON) FATHER, MOTHER, YOUNGESTOFFSPRING, ELDERSIBLING
);

reference(PERSON) procedure YOUNGESTUNCLE (reference(PERSON) R);
    begin
        reference(PERSON) P, M;
        P := YOUNGESTOFFSPRING(FATHER(FATHER(R)));
        while (P ¬= null) and (¬ MALE(P)) or (P = FATHER(R)) do
            P := ELDERSIBLING(P);
        M := YOUNGESTOFFSPRING(MOTHER(MOTHER(R)));
        while (M ¬= null) and (¬ MALE(M)) do
            M := ELDERSIBLING(M);
        if P = null then 
            M 
        else if M = null then 
            P 
        else 
            if AGE(P) < AGE(M) then P else M
    end

[edit] External links

• Niklaus Wirth & C. A. R Hoare (1966) A contribution to the development of ALGOL. Communications of the ACM, Vol.9, pp. 413 - 432
• Stanford Computer Science Department Technical Report CS-TR-68-89 Various documents for Stanford University's 1972 implementation of Algol-W. The report includes the Algol W Language Description.
• Algol W @ Everything2 An informal but detailed description of the language by a former user, with sidebars extolling Algol W over Pascal as an Educational programming language.