Re: [bug] org-link-escape and (wrong-type-argument stringp nil)

[Sebastian Rose <sebastian_rose@gmx.de>]

David Maus <dmaus@ictsoc.de> writes:
> Sebastian Rose wrote:
>>Is there a reason for this distinction between multibyte and unibyte?
>>I favour the "shotgun-approach" if not.  It's bullet-proof.
>
>>The JavaScript function `encodeURIComponent()' encodes the German Umlaut
>>`ü' as `%C3%B6' regardless of the sources encoding actually.  That's why
>>I wrote the two functions `org-protocol-unhex-string' and
>>`org-protocol-unhex-compound' (s. org-protocol.el).
>
> Ah, yes.  From my understandig of the RFC %C3%BC is a valid
> representation of the "ü" character.  
>
> I do not yet fully understand
> how to unescape such a representation.  E.g. Is %C3%BC a hexencoded
> multibyte char or a succession of two singlebyte chars?


It's a hexencoded multibyte char.

JavaScript implementations seem to turn non-ascii singlebyte chars into
multibyte chars first, then encode the result.

This means if a page is iso-8859-1 encoded (singlebyte `ü'), JavaScript
will recode the `ü'.  It's funny, but that's what I found when writing
org-protocol.el 


`org-protocol-unhex-string' and `org-protocol-unhex-compound' decode
such a representation.

The trick is in the utf-8 encoding itself.  If a byte starts with a 1,
another byte will follow.  The number of leading `1's denotes the amount
of bytes used for one character.   On a GNU/Linux system try

  sh$  man utf-8


Sebastian