[luatex] "nop" in virtual fonts

[Ulrike Fischer]

Am Fri, 25 Mar 2011 07:56:48 +0100 schrieb Taco Hoekwater:

> On 03/24/2011 05:22 PM, Ulrike Fischer wrote:
>> The luatex manual mentions in the section about virtual fonts the
>> command "nop" which should do nothing.
>>
>> But when I tried it in a virtual font
>>
>> chars[u].commands=  {{'nop'}}
>>
>> I got a lot of messages
>>
>> unknown packet command nop!
> 
> Strange, should work. Can you provide a small test file please?

OK. 

In the context minimals there is in tex\generic\context a
luatex-fonts-demo-vf-1.lua (written by Hans).

If one compile (in context minimals updated some days ago)  the
document below which use this virtual font one gets a three colored
text.

Now if I exchange line 27

- v.commands = { color[n], { 'slot', n, u }, color[0]}
+ v.commands = { color[n], { 'slot', n, u }, color[0], {'nop'}}

I get

unknown packet command nop!
PANIC: unprotected error in call to Lua API (bad argument #-1
(number expected,
got nil))

If I use

- v.commands = { color[n], { 'slot', n, u }, color[0]}
+ v.commands = { {'nop'}}

the document compiles but I get tons of the messages "unknown packet
command nop!"

I:\Z-Test>luatex --version
This is LuaTeX, Version beta-0.66.0-2011031911 (Web2C 2010) (rev
4093)


\starttext
  \font\mine=file:luatex-fonts-demo-vf-1.lua at 12pt
  \mine \input tufte \par
\stoptext

-- 
Ulrike Fischer