editor.CharAt

[mozers]

Hello Scite-interest!

I'm tormented by curiosity.
editor.CharAt returns an unsigned integer.
And though conversion is simple (editor.CharAt[x] % 256), in lua unsigned integers are not used.
It is a defect or unfathomable wisdom?
Neil, you will accept a patch?

--
mozers
<http://scite.net.ru>

[Philippe Lhoste]

On 11/10/2009 11:21, mozers wrote:
> editor.CharAt returns an unsigned integer.
> And though conversion is simple (editor.CharAt[x] % 256), in lua unsigned integers are not used.
> It is a defect or unfathomable wisdom?

That's probably because it is a blind, automatic interface to the

# Returns the character byte at the position.
get int GetCharAt=2007(position pos,)

Scintilla message, like most Lua bindings/functions.

Why do you do modulus? You can get more than one byte with Unicode
characters?

--
Philippe Lhoste
-- (near) Paris -- France
-- http://Phi.Lho.free.fr
-- -- -- -- -- -- -- -- -- -- -- -- -- --

[Neil Hodgson]

mozers:

> I'm tormented by curiosity.
> editor.CharAt returns an unsigned integer.

Don't you mean signed? The C 'char' type is signed on most commonly
used platforms.

> And though conversion is simple (editor.CharAt[x] % 256), in lua unsigned integers are not used.
> It is a defect or unfathomable wisdom?
> Neil, you will accept a patch?

No. It would break existing code.

Neil

[mozers]

Sunday, October 11, 2009, 1:37:37 PM, Philippe wrote:

>> And though conversion is simple (editor.CharAt[x] % 256), in lua unsigned integers are not used.

> Why do you do modulus? You can get more than one byte with Unicode characters?

For characters with code from 0 to 127 editor.CharAt returns the correct values.
For characters with code from 128 to 256 editor.CharAt returns a negative value.
e.g.
char=} asciiCode=125 editor.CharAt return 125
char=~ asciiCode=126 editor.CharAt return 126
char= asciiCode=127 editor.CharAt return 127
char=Ђ asciiCode=128 editor.CharAt return -128
char=Ѓ asciiCode=129 editor.CharAt return -127
char=‚ asciiCode=130 editor.CharAt return -126

You can check it
print(editor.CharAt[editor.CurrentPos])

Transform to real ascii code variant 1:
if char_at < 0 then char_at = 256 + char_at end

Transform to real ascii code variant 2:
char_at = char_at % 256

--
mozers
<http://scite.net.ru>

[mozers]

Sunday, October 11, 2009, 3:37:03 PM, Neil wrote:

>> editor.CharAt returns an unsigned integer.
> Don't you mean signed? The C 'char' type is signed on most commonly used platforms.

I try to explain a detail in the prev post to Philippe.

>> in lua unsigned integers are not used.
>> It is a defect or unfathomable wisdom?
>> Neil, you will accept a patch?
> No. It would break existing code.

If you do not think this is a mistake, then I - retreat.

--
mozers
<http://scite.net.ru>