Fortran Specialist Group

Summary of discussion on Fortran 2008

This is a summary of the discussion at the Fortran Specialist Group meeting on 14th June 2007. It followed presentations by John Reid and David Muxworthy on the revision of the current (2003) Fortran standard.

The request for comment from Fortran users at large and from FSG members in particular had brought no response whatever; the only input had been from those already involved in the standards process. This was thought to be because users in general were not yet familiar with Fortran 2003 (or even with earlier versions in some cases) and hence were not yet concerned about proposals for the future.

There was general agreement that the schedule for the revision had been too optimistic; the caveats attached to the schedule had been overlooked. There must be some experience with F2003 compilers before the next revision is finalized. David Hill's point from the "Fifty Years of Fortran" meeting in January was mentioned, viz. that the appearance of Algol 60 too soon after Algol 58 had undermined the view of Algol as a stable platform and had helped Fortran to win out over Algol.

Delaying the schedule would however mean a new request to SC22. There was concern that delay should not open the floodgates to new proposals. There would still be much work for J3 to do on interpretations and on developing the interoperability facility which had fallen behind schedule.

On current planning, NAGWare f95 will have most of F2003 in the next release and nearly all of F2003 in the 2009 release. It might be 2010 before the whole language is completely implemented. Thus they feared that if a new standard were finalized in 2008, particularly if it included large features like co-arrays, they would never catch up. The same would be true of other vendors and the danger of suppliers abandoning Fortran development altogether was mentioned.

There was discussion in general terms about whether this revision should be a minor one, as was originally intended, and the remaining time was largely spent on discussing the three main items being implemented.

Intelligent macros were thought to be useful but not essential. Their removal would not have a significant effect on the size of the language and the feature did not generate strong feelings for or against.

Co-arrays were said to have become bloated beyond the original Reid-Numrich proposal and would benefit from reduction, as outlined on page 9 of John Reid's paper. There was discussion on whether co-arrays should be in the standard or in a TR, with strong feelings both ways. For one participant co-arrays in the standard could not come too soon. On the other hand the fundamental conceptual model of co-arrays was queried and the presentation in the standard, whereby parallel programs became the norm, and all existing (and future non-co-array) Fortran programs became special cases, was considered unfortunate.

Given the e-mail debate in the BSI panel prior to the meeting, a summary of which had appeared on the FSG website, there was relatively little discussion of BITS and no-one spoke for the proposal.

It was suggested that if it were still required to remove items from the standard then the additional mathematical functions and the changing of the maximum array rank to 15 could be candidates; in the latter case one possibility would be to keep the maximum array rank at 7 and to have a maximum co-array rank of 7.

The following straw votes were taken:

  • leave co-arrays as now: 0; reduce as outlined by John Reid: 8; undecided: 2.
  • keep co-arrays in the standard: 3; move co-arrays to a TR: 3; undecided: 4.
  • keep BITS in the standard: 0; move to a TR: 3; remove altogether: 6; undecided: 1.
  • keep macros in the standard: 6; move to a TR: 3; undecided: 1.
  • keep the schedule: 1; slip by two years: 7; undecided: 1.

David Muxworthy
19th June 2007

Comments on this or any other of the Group's pages should be sent by email to the FSG Web Editor.
Valid XHTML 1.0 Transitional Valid CSS!

Last modified: Sun 9 Dec 2012 00:10:30