[luatex] protect_glyph

[luigi scarso]

On Mon, Jul 4, 2011 at 12:08 PM, Patrick Gundlach <patrick at gundla.ch> wrote:
>
> Am 04.07.2011 um 12:01 schrieb luigi scarso:
>
>> On Mon, Jul 4, 2011 at 11:50 AM, Patrick Gundlach <patrick at gundla.ch> wrote:
>>> Hi,
>>>
>>> why is the function protect_glyph called "protect..."? What does it protect?
>>>
>>> Patrick
>>>
>>>
>>> (who is slightly embarrassed to ask this question)
>>>
>>>
>> (a little old trunk/source/texk/web2c/luatexdir/lua/lnodelib.c)
>>
>> static int lua_nodelib_protect_glyphs(lua_State * L)
> [...]
>> static int lua_nodelib_unprotect_glyphs(lua_State * L)
> [...]
>
> I still don't quite understand what it protects from? The source and the manual are stating the same, so I am not sure what I can read from the source.
>
> Patrick
>
>
>
>
>
what is
subtype(head)
and why 256 is important for it ?
-- 
luigi