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I have written the following simple routine, which may separate the "man-compilers" from the "boy-compilers" - D. E. Knuth.
Original ALGOL 60 program by Knuth, different values obtained by modifying the "10" in the last line.
begin
real procedure A (k, x1, x2, x3, x4, x5);
value k; integer k;
begin
real procedure B;
begin k:= k - 1;
B:= A := A (k, B, x1, x2, x3, x4);
end;
if k <= 0 then A:= x4 + x5 else B;
end;
outreal (A (10, 1, -1, -1, 1, 0));
end;
Smalltalk:
Integer>>manOrBoy
^self x1: [1] x2: [-1] x3: [-1] x4: [1] x5: [0]
Integer>>x1: x1 x2: x2 x3: x3 x4: x4 x5: x5
| b k |
k := self.
b := [ k := k - 1. k x1: b x2: x1 x3: x2 x4: x3 x5: x4 ].
^k <= 0 ifTrue: [ x4 value + x5 value ] ifFalse: b
Example: '10 manOrBoy' returns -67
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