[tordek]

But that makes no sense, it is whitespace, and it has semantic significance (hence being significant). Whitespace was not significant in older versions of Fortran, and that allowed you to write

    DO30I=10,100

which was interpreted as

    DO 30 I = 10, 100

An amusing bug I saw in Expert C Programming mentioned how somebody once typed e dot instead of a comma, and

    DO 30 I = 10. 100

ended up interpreted as a simple real assignment:

    DO30I = 10.1