Compulsory spaces in free source form

From: John Harper (harper_at_mcs.vuw.ac.nz)
Date: 09/30/04 

Date: Wed, 29 Sep 2004 22:06:31 GMT

The f95 standard requires a blank between a statement keyword, name,
constant or label and an adjacent name, constant or label in free source
form, and it's obvious why if, for example, a constant has a name. But
it's a pity that the rule prevents things like STOP'Now' where ambiguity
is impossible. (Some compilers e.g. g95 catch this error, others don't.)

But there are cases like PRINT* and STOP666 where the * or the 666 seems
not to be a name, constant or label (666 in some contexts is a constant
but here it's a string of up to 5 digits). The blank is then presumably
not needed, even though STOP666 looks as if it could also be the name
of a variable. F95 compilers disagree on how they treat the program
below; is it standard-conforming in free source form?

    STOP666 = 666
    PRINT*,'STOP666 =',STOP666
    STOP666
    END

John Harper, School of Mathematics, Statistics and Computer Science,
Victoria University, PO Box 600, Wellington, New Zealand
e-mail john.harper@vuw.ac.nz phone (+64)(4)463 5341 fax (+64)(4)463 5045