forums.silverfrost.com

[JohnCampbell]

Intel ifort defines 3 source forms; fixed, free and tab.
The tab form appears to be an adaptation of the fixed form and describes a special interpretation of the tab character in columns 1 to 5 then subsequent tabs appear to be associated with columns 9, 18, 27 etc, using an 8 space field. (can't guarantee I have this correct as I have never used this approach.)

I have found when receiving tab form source, other IDE's and compilers do not recognise this source form and so it must have limited portability.

In the old Lahey F95 compiler I have, I can't find any reference to the use of tab characters in source. It may treat it as any number of spaces.
If tabs were interpreted as 3 spaces, I probably would have adopted it for DO loop indentation many years ago, but 8 spaces is too much.
They simply cause confusion when skipping between IDE's, so my old line editor that I used in 80's removes them.

I am certainly not recommending FTN95 adopts this form, which I can't find in any Fortran standard.

John

[IanLambley]

Tabs are dangerous - I never use them. I nearly always use fixed format due to my advancing age and use the following scheme:
1. Statement and format numbers have 4 digits: type <space> and the number then <space> and carry on with the line
2. Continuation lines: 5*<space> <apersand>
3. Indentation +-2 spaces per level.
4. Normal lines: 6*<space> then the indentation then the line.

I posted a fix for tabbed files some years ago, see:
http://forums.silverfrost.com/viewtopic.php?t=785&highlight=untab
Ian

[LitusSaxonicum]

Mecej4, thanks for the clarification. So, if you have IMPLICIT NONE (implicitly or explicitly) then all your function names that are provided in separate source files need to have their type declared somehow? How do you know what is in scope until linking if you have separately compiled files? I'm too old a dog for this new trick.

Dan, TABs were always an extension. On IBM model 26 and 29 card punches, you could press the TAB key, but it always gave you spaces by advancing the card in the punch.

My recollection is that Hollerith cards used a 6-bit code, thus excluding many control characters in the resulting 64-character set. The TAB character wasn't part of the character set. We Brits often used 8-hole punched tape, giving us a 7-bit code allowing 128 characters (the 8th hole was used for a parity check as the punches weren't reliable). This opened up a whole range of extra characters, including control characters, and the adoption of terminal-based systems allowed 256-character codes with even more.

Thus, TAB is original sin, no matter how useful it has been.

Eddie

[mecej4]

[LitusSaxonicum]

OK, I see how it reports the error. An education for me.

I can't help but feel that with every passing iteration, Fortran looks more like Algol, but never quite gets there.

Thanks for the reminder about how the tabs were set, I'd forgotten. I preferred the modernist look of the 029 to the Art Deco Cinema look of the 026, but I expect that the guts were the same.

Eddie

[mecej4]

The Generic utility that John Silver referred to has no bearing on the FTN95 error message regarding the colon. To see that, change the code of the loop to the following:

[JohnCampbell]

Dan,
I downloaded your file defect.for and listed it with my utility to expose control characters. It lists as:

[JohnCampbell]

Eddie,

From memory the 029 was much preferred to the 026, as it had more capabilities. I just can't remember what those capabilities were !

Just about every day, I would catch the bus to uni, go to the physics building, pick up the overnight run, go to the card punch room in the basement and look to see if there were any 029 desks free. It almost never happened ! Always too late. Never a thought about indenting do loops in those days, just hoping there were no typing errors, or another day lost.

Back to tabs; there are two possible interpretations. FTN95 appears to replace the tab with 8 spaces, while other interpretations move the next character to the size 8 grid or what ever the spacing is.
I just tried notepad, which has the grid approach, but the column count in the status bar does not agree.

Further, I opened Dan's defect.for in PLATO and it does not display the tabs in a way that FTN95 interprets. This is a problem ?

John

[DanRRight]

You are right, guys, this / is in column 73. But how this happened? I checked that twice and saw it at reliably below of that (and i always care about that limit with the eagle eye) ? Don't understand that...Still a damn devilry. I feel bad like aging Dersu Uzala when he for first time missed his bullet into Siberian tiger.

[mecej4]

[DanRRight]

Mecej4 - We discussed here limit checking few times before, both 72 and 132.
1) First my shield is editor, it shows cursor position, there is no discrepancy between editor and FTN95
2) i made 73 character barrier width of editor for fixed code and larger for 132 one as it has two panels each for different types of sources. But recently i had desktop shuffling and probably changed the sizes
3) i periodically use built into the code source limit checking subprogram i wrote hell decades ago. Basically the code checks itself. Seems I have to make it working automatically every hour by default
4) i strongly advocated for the use of /no_truncate compiler option as default but it was buggy few times and only recently fixed as Paul reported. If this option worked fine this thread would not exist! No tab hatred would be here either. I have nothing against of use of tabs.

That was why i was so sure that this was some kind of devilry because i believed in all my not breakable shields and setups not in the compiler diagnostics.

[mecej4]

Which editor do you use?

[DanRRight]

NoteTab

(awards from PC Magazine, PC World and WUGNET, 3 times Shareware Industry Awards)

[mecej4]

I did not know about this editor. I downloaded a trial version, opened your file defect.for in it, set the tab size to 8 ( to match FTN95 ) and tab type to 'fixed'. The slash in line-8 was shown in column 73. This is as things should be, but without a visual aid it can be hard to look for that specific column. Other editors show a dotted line at a specified right margin (such as column 72). Perhaps Notetab can do so, too, but I have not found the menu to make that setting effective.

If you are going to rely on your source checker, perhaps you should investigate why it failed in this rather simple case.

[jalih]

I personally use SPFLite as my source editor. If you have some experience with ISPF or have to edit a lot of old fixed format source files, then its a great tool.

On SPFLite, the visual column markers could be defined, but you could also type a command: