*   early FORTRAN had an arithmetic IF statement (see PDF 5)

*   a little-bit-later FORTRAN also added a
    logical IF-statement:

IF (X .EQ. A(I)) K = I - 1

    ...but note that is a SINGLE statement when the condition
    is true; the idea of a block comes with Algol-58/Algol-60!

*   in early FORTRAN, the GOTO and its variants
    are the WORKHORSE of control flow;

another FORTRAN goto: assigned GOTO

GOTO N, (L1, L2, ... Ln)

...which must be used with ASSIGN

ASSIGN 20 to N

...which puts the ADDRESS of STATEMENT 20 into variable N

*   IN early FORTRAN, the DO loop COULD be nested --
    not very many statements could;

    Algol-58, Algol-60 introduce the idea of block-structures;
    (the idea that you can put a block ANYWHERE a statement -
    that it can be treated as a statement -- is from Algol-60!)

    Algol-60 -- like 2nd generation languages -- tended toward
    baroque, richly-featured control structures;
    
    Algol-60 for loop:

    for var := expr step exrp1 until expr2 do sttmt

    or
   
    for var := expr while expr do stmt

    or 

    for var := 31, 38, 40, 27 do stmt

    and more...

    for i := 3, 7,
             I1 step 1 until 16,
             i/2 while i >= 1,
             2 step i until 32
    do print (i)
   
    *   rich to the point of being hard to implement,
        and hard to read/understand;