Deprecate unused features in lex.ll

maintainers
#1

There are three constructs in the lexer that are obsolete and that issue warning messages when they are used. The first of these is using the '...' construct as a line continuation inside of a double quoted string. The decision was made in this thread Support line continuations within single-quoted strings? - #7 by rik to deprecate that usage in Octave version 7 and remove it completely in Octave version 9.

Should the other two constructs which are obsolete also be deprecated? They are

  1. Using '\' as a line continuation character. The issue is that this looks like left division.
octave:1> x = 5 \
warning: using continuation marker \ outside of double quoted strings is deprecated and will be removed from a future version of Octave, use ... instead
  1. Extra white space characters after line continuation character in double-quoted strings.
str = "abc \   
warning: white space and comments after continuation markers in double-quoted character strings are obsolete and will not be allowed in a future version of Octave
#2

Yes from my side :slightly_smiling_face:

#3

It turns out that this warning isn’t even correct. Octave warns on whitespace characters, but absolutely rejects and errors out on comments after continuation markers. I made a change to update the warning message (octave: 2034a2ab58d8), but I also think these two warnings should just be deprecated and removed.

#4

I went ahead and deprecated the remaining two warning messages since there didn’t seem to be an objection. See octave: 01679f865fc7.

1 Like
#5

Seems fine to me. Is the behavior of the lexer OK and it is only the warnings that are a problem or is there some change that also needs to be made in the way the lexer is handling this input?

#6

No change to lexer required. This was just about issuing unnecessary warnings.