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register a callback on macro expansion?

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Jjgod Jiang

20 Feb 2007 20 Feb '07

1:35 a.m.

Hi, I'm wondering if I can register a Lua function as callback on the expansion of a specific macro? I'm expecting something like this: \def\hello#1{#1} callback.register("macro.hello",lua_func_hello) when using \hello{abc}, the lua_func_hello will get called and have access to the arguments of \hello (abc). In this way, we can implement loop structure in lua (which I think is a cleaner way than tail recursion in TeX). - jjgod.

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Hans Hagen

20 Feb 20 Feb

9:49 a.m.

Jjgod Jiang wrote:

Hi,

I'm wondering if I can register a Lua function as callback on the expansion of a specific macro? I'm expecting something like this:

\def\hello#1{#1}

callback.register("macro.hello",lua_func_hello)

when using \hello{abc}, the lua_func_hello will get called and have access to the arguments of \hello (abc).

\def\hello#1{\directlua 0 {YourFunction("#1")}} Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------

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Jjgod Jiang

12:07 p.m.

Hi, 2007/2/20, Hans Hagen :

\def\hello#1{\directlua 0 {YourFunction("#1")}}

Yep. That works (but not for lua state 0, I use state 1 instead.) But I'll need the slunicode library to process string like this, is it available now? I have not found it on luatexref-t.pdf. Thanks. - jjgod.

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Hans Hagen

12:18 p.m.

Hi,

2007/2/20, Hans Hagen :

...
\def\hello#1{\directlua 0 {YourFunction("#1")}}

Yep. That works (but not for lua state 0, I use state 1 instead.) But I'll need the slunicode library to process string like this, is it available now? I have not found it on luatexref-t.pdf.

Jjgod Jiang wrote: this is state independent, so state 1 should work; indeed the slunicode lib is there as is lfs Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------

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Jjgod Jiang

12:33 p.m.

Hi, 2007/2/20, Hans Hagen :

this is state independent, so state 1 should work; indeed the slunicode lib is there as is lfs

I've tried with \directlua 0 { function hello(str) tex.print(str) end } \def\hello#1{\directlua 0 {hello("#1")}} \hello{hi} \bye But only got: ! LuaTeX error [string "luas[0]"]:1: attempt to index global 'tex' (a nil value ). \hello #1->\directlua 0 {hello("#1")} l.9 \hello{hi} - jjgod.

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Taco Hoekwater

12:52 p.m.

Jjgod Jiang wrote:

But only got:

! LuaTeX error [string "luas[0]"]:1: attempt to index global 'tex' (a nil value ).

Which snapshot are you using? It looks like a bug that was present a month or so ago. Cheers, Taco

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Jjgod Jiang

2:12 p.m.

Hi, 2007/2/20, Taco Hoekwater :

Which snapshot are you using? It looks like a bug that was present a month or so ago.

I was using snapshot-20070202 just then. It's ok now in snapshot-20070218. Thanks. - jjgod.

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Hans Hagen

12:56 p.m.

Jjgod Jiang wrote:

Hi,

2007/2/20, Hans Hagen :

...
this is state independent, so state 1 should work; indeed the slunicode lib is there as is lfs

I've tried with

\directlua 0 { function hello(str) tex.print(str) end }

\def\hello#1{\directlua 0 {hello("#1")}}

\hello{hi} \bye

But only got:

! LuaTeX error [string "luas[0]"]:1: attempt to index global 'tex' (a nil value ). \hello #1->\directlua 0 {hello("#1")}

l.9 \hello{hi} \starttext

\directlua 0 { function hello(str) tex.print(str) end } \directlua 5 { function hello(str) tex.print(str) end } \directlua 0 { tex.print("HELLO") } \directlua 5 { tex.print("HELLO") } \directlua 0 { hello("HELLO") } \directlua 5 { hello("HELLO") } \def\hello#1{\directlua 5 {hello("#1")}} \hello{HELLO} \stoptext works ok here (1 too) so there is another problem; it could be that luatex is not in luatex mode or that somehow the tex table gets messed up Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------

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Taco Hoekwater

10:08 a.m.

Hi Jjgod, Jjgod Jiang wrote:

Hi,

I'm wondering if I can register a Lua function as callback on the expansion of a specific macro? I'm expecting something like this:

\def\hello#1{#1}

callback.register("macro.hello",lua_func_hello)

when using \hello{abc}, the lua_func_hello will get called and have access to the arguments of \hello (abc).

In this way, we can implement loop structure in lua (which I think is a cleaner way than tail recursion in TeX).

Not right now, but soon. (perhaps using a slighly different interface, because your example makes the macro definition body pointless, and that can be confusing). Cheers, Taco

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Hans Hagen
Jjgod Jiang
Taco Hoekwater