Thunderbird mailer

[Shachar Shemesh]

On 08/19/2011 08:13 AM, Dotan Cohen wrote:

> Really? Was is the effect of  embedding paragraph direction in HTML?
> What is the effect of the character that I posted? How do they differ?
On the theoretical level, an RLE at the beginning of the paragraph means
to embed an RTL run inside the paragraph. This means that you have a
basically LTR paragraph with the actual text inside an RTL run. This
goes to paragraph alignment - an LTR paragraph should be left aligned.
You could claim that the paragraph auto-detection will do the rest, but
if that were true, you could put an RLM instead of an RLE at the
beginning of the paragraph.

There is also an hypothetical case that of unbalanced PDFs reverting the
effect, but I'm only bringing it up as a side note, as I agree that for
all practical purposes, this is irrelevant.

On the practical level, many implementations (Windows' edit control
included) do line breaks and only then BiDi. As a result, all state is
lost at the end of the line, and the RLE only covers the first line of
the paragraph. Since most mailers (thunderbird included) do explicit
line breaking in text mode, this is not even necessarily a violation of
the standard, as RLEs should be forgotten at the paragraph end character
(a fact you rely on when you put an RLE at the beginning, but not a PDF
at the end).

Shachar

-- 
Shachar Shemesh
Lingnu Open Source Consulting Ltd.
http://www.lingnu.com