Fortran

About APL, ... Eric Smith wrote: So this is not a syntax question, but a semantic one. Similar with FORTRAN: assume you wanted to write DO 20 I = 1,5 WRITE (LUNUTO, 10) 10 FORMAT (' Hello world!') 20 CONTINUE which happens to be a loop that outputs the text from the FORMAT statement five times, but put the first line slightly wrong like DO 20 I = 1.5 then this line does not start a loop any more, but becomes a simple assignment to a variable named DO20I, implicitly typed as REAL. This happens because FORTRAN is, by definition, blind to spaces (!), except in string constants. Incidentally, many FORTRAN compilers require that the comma is on the first line of a DO statement, while anything beyond it is allowed to be on continuation lines. Decades ago, I used to have a demo program that contained lots of things like this, and whenever somebody claimed to be an experienced FORTRAN programmer, I asked them to predict the output. Nobody ever got it right completely. Of course, many of the surprises were implementation dependant, and it was impossible to port the program from TOPS-10 to VAX/VMS. The above example, however, *is* portable. Just make sure LUNUTO (logical unit for user terminal output) has a value that is appropriate for your favorite operating system/compiler combo (e.g., for TOPS-10, LUNUTO=5, for VMS LUNUTO=6). -- Andreas Freiherr Vishay Semiconductor GmbH, Heilbronn, Germany http://www.vishay.com