Re: [vile] ANN: vile-9.8s

[Thomas Dickey]

On Sun, Dec 18, 2016 at 01:20:26PM +0100, j. van den hoff wrote:
> thanks a lot for the new version. regarding the (k)sh syntax filter
> I can confirm that the reported problems are gone.

:-)
 
> while testing a bit further I noted that there persists (a so far
> seemingly unreported) minor glitch in the tcl syntax filter, it
> seems:
> 
> I see strange spurious highlighting by reverse video in constructs like
> 
> [1G
> 
> (the `1G' shows up in reverse video (red in my case))
> 
> strangely this happens ony if _not_ in line one. even more strangely
> it does also not happen in, e.g.,
> 
> [1A
> 
> I have encountered the problem when defining constants containing
> escape sequences, e.g. like
> 
> set gobol  {^[[1G}

yes...  tcl is harder to parse reliably than it looks, since its
designers chose to use curly-braces to mean (from the user's point of
view) different things.  That makes it hard to parse with a lex-based
filter, since matching curly-braces has to be recursive - something
that lex can only approximate with a stack of different states.

For this chunk, my filter tries to see that as a regular expression
because of the "^", and then sees the doubled "[" and decides it can't
be that because the closing curly brace (and end of line) comes before
it finds a valid regex.  So it treats the "[" characters specially,
and falls into the "1G" not being a number.

Rather than showing it as an error, I could modify that to just
treat it as a literal (but the downside is that if it were meant
to be a regex, then it would have been an error).

I _could_ rewrite that in C (as I did for perl and ruby) and get
proper recursion...
 
> to move cursor to beginning of line (^[ denoting escape (octal
> 033)). you can also see the problem with this silly example:
> 
> proc 1G {return bla}
> puts [1G]

This case is a little different, but again, the leading "1" makes it
think that should be a number, but the "G" tells it that it's not.
 
> note that the reverse video might only appear after deleting and
> reinserting the line containing the `[1G' construct.
> as an aside: in this example the proc name is furthermore
> highlighted as a reserved word (like proc). maybe both problems are
> related?
> 
> thanks for `vile'
> 
> joerg
> 
> On Sun, 18 Dec 2016 03:15:10 +0100, Thomas Dickey <address@hidden> wrote:

-- 
Thomas E. Dickey <address@hidden>
http://invisible-island.net
ftp://invisible-island.net

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