David Muxworthy, ISO Fortran standards committee (WG5) Corrigenda editor and member of BCS (formerly British Computer Society) recently sent along a fascinating document. It comes from a project to digitize old papers from the archive of the BCS Fortran Specialist Group and is a 1977 summary of changes made to FORTRAN 77 as a result of the public comment review.

What’s astonishing is the number of significant changes made to the language at this late stage in the standard’s development. I knew about the change to PARAMETER, that resulted in DEC’s VAX FORTRAN having to support both the form from the draft standard (without parentheses and type coming from the constant) and that of the final standard (with parentheses and the type coming from the identifier.) But I didn’t know of many other last-minute changes and additions to the language, including:

  • IF-THEN-ELSE
  • IOSTAT
  • .EQV. and .NEQV.
  • Assumed-size arrays

and many more.

Also interesting was seeing the number of suggestions rejected for FORTRAN 77 that made their way into Fortran 90 and later standards, such as:

  • Semicolon statement separators
  • NAMELIST
  • DOUBLE COMPLEX
  • Requiring DO loop control variables to be INTEGER

It’s a fun read, though as with many OCRed documents, there are uncorrected scanning errors.

I am fairly certain that we won’t be seeing this level of flux after the comment period for Fortran 2015. (At least I hope not!)

(Originally posted at Intel Developer Zone, copied with permission)

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