[Lazarus] TMask revisited

[Bart]

On Sat, Oct 23, 2021 at 11:33 PM Bart <bartjunk64 at gmail.com> wrote:


> I renamed mocOptionaChar to mocSet and added some comments in the code.
>
> @José: are these comments correct?


I'm still strugling with the difference between mocRange and mocSet
(previously mocOptionalChar).
Consider the following mask: [a-c]
With [mocRange] this matches 'a', 'b', or 'c', but not '-'.
With [mocSet] this matches 'a', '-' or 'c', but not 'b'.
That's clear to me.

Mask [ac]
[mocRange]: matches 'a' or 'c'.
[mocSet]: matches 'a' or 'c'.
To me this seems as [mocRange] is equivalent to  [mocRange,mocSet]
So, only mocSet without mocRange has a special meaning.
Or they should be mutually exclusive: if you enable mocSet, mocRange
should be disabled and vice versa (the latter does not cause any
functional change).

Now we take into account the mocEscapeChar and things get a little confusing.
IIUC then if mocEscapeChar is eneabled, then EscapeChar+SomeChar is
interpreted as just a literal SomeChar.
By default EscapeChar = '\' so '\*' is  a literal '*' and '\\' is a literal '\'.
And '\-' should mean a literal '-'.

In the following examples RangeAutoReverse is set to FALSE.

Opcodes : [mocRange]
Mask    : [a\-]
Filename: -
EMaskError: Missing closing character "]" in mask (offset 5).
This is to be expected.

Opcodes : [mocRange,mocEscapeChar]
Mask    : [a\-]
Filename: -
EMaskError: Missing closing character "]" in mask (offset 5).      ********** ?
Escaping the '-' should mean that the mask should match 'a' or '-'

Opcodes : [mocSet]
Mask    : [a\-]
Filename: \
Matches
This is expected

Opcodes : [mocSet,mocEscapeChar]
Mask    : [a\-]
Filename: \
Matches
Since mocEscapeChar is enabled the sequence '\-' should be interpreted
as a literal '-' and it should therefore not match '\'.

Some more oddities:
Opcodes : [mocRange]
Mask    : [$\-&]
Filename: $
Matches

Opcodes : [mocRange]
Mask    : [$\-&]
Filename: %
Does NOT match

Opcodes : [mocRange]
Mask    : [$\-&]
Filename: &
Does NOT match
Actually OK, since the range '\-&' is not reversed and therefore empty
(took me a while to realize that)


Opcodes : [mocRange]
Mask    : [$\-&]
Filename: -
Does NOT match

Opcodes : [mocRange]
Mask    : [$\-&]
Filename: \
Does NOT match



Opcodes : [mocRange,mocEscapeChar]
Mask    : [$\-&]
Filename: $
Matches

Opcodes : [mocRange,mocEscapeChar]
Mask    : [$\-&]
Filename: %
Does NOT match

Opcodes : [mocRange,mocEscapeChar]
Mask    : [$\-&]
Filename: &
Does NOT match              ************ ?
Looks like '\-&' is interpreted as an (empty) range, but '\-' should
be interpreted as a literal '-', so not a range but a set, and it
should match

Opcodes : [mocRange,mocEscapeChar]
Mask    : [$\-&]
Filename: -
Does NOT match              ************ ?
Same argument as above

Opcodes : [mocRange,mocEscapeChar]
Mask    : [$\-&]
Filename: \
Does NOT match


With [mocSet] instead of [mocRange]

Opcodes : [mocSet]
Mask    : [$\-&]
Filename: \
Matches


Opcodes : [mocSet,mocEscapeChar]
Mask    : [$\-&]
Filename: \
Matches                     ************ ?
Here enabling mocEscapeChar makes no difference at all. (Checked the
same filenames as with mocRange)

Finally this:
Opcodes : [mocRange]
Mask    : [\a-c]
Filename: \
Matches

Opcodes : [mocRange,mocEscapeChar]
Mask    : [\a-c]
Filename: \
Matches                     ************ ?
It should not.

It looks like escaping does not work as advertised?
-- 
Bart