Fortran scanner misses comments in some cases about scons

[mwichmann]

To follow up on the final paragraph of the issue, in order to strip comments, we'd need to understand the syntax involved. The complication, as always, is context: if it's in a string (though Fortran does not use that terminology) it should not be considered a comment indicator.

From the standard:

6.3.2.3 Free form commentary
The character “!” initiates a comment except where it appears within a character context. The comment extends to the end of the line. If the first nonblank character on a line is an “!”, the line is a comment line. Lines containing only blanks or containing no characters are also comment lines. Comments may appear anywhere in a program unit and may precede the first statement of a program unit or follow the last statement of a program unit. Comments have no effect on the interpretation of the program unit.

6.3.3.2 Fixed form commentary
The character “!” initiates a comment except where it appears within a character context or in character position 6. The comment extends to the end of the line. If the first nonblank character on a line is an “!” in any character position other than character position 6, the line is a comment line. Lines beginning with a “C” or “*” in character position 1 and lines containing only blanks are also comment lines. Comments may appear anywhere in a program unit and may precede the first statement of the program unit or follow the last statement of a program unit.

Note that the existing regex does not attempt to recognize the fixed form "C or * in column 1".

and

3.21 character context
within a character literal constant (7.4.4) or within a character string edit descriptor (13.3.2)

And for the scanner issue, which incolves inline statement termination, here's the wording:

6.3.2.5 Free form statement termination
If a statement is not continued, a comment or the end of the line terminates the statement.
A statement may alternatively be terminated by a “;” character that appears other than in a character context or in a comment. The “;” is not part of the statement. After a “;” terminator, another statement may appear on the same line, or begin on that line and be continued. A sequence consisting only of zero or more blanks and one or more “;” terminators, in any order, is equivalent to a single “;” terminator.

6.3.3.4 Fixed form statement termination
If a statement is not continued, a comment or the end of the line terminates the statement.
A statement may alternatively be terminated by a “;” character that appears other than in a character context, in a comment, or in character position 6. The “;” is not part of the statement. After a “;” terminator, another statement may begin on the same line, or begin on that line and be continued. A “;” shall not appear as the first nonblank character on an initial line. A sequence consisting only of zero or more blanks and one or more “;” terminators, in any order, is equivalent to a single “;” terminator.