Hello! I am trying to redefine the ’open_read_file’ callback. I am getting this error: callback ’open_read_file’ is frozen Why is it "frozen"? Can I "unfreeze it"? André Caldas.
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I am trying to redefine the ’open_read_file’ callback.
Hi André, direct callback access is disabled. There are usually some layers of abstraction on top of them, different ones for different callbacks. Mapping them all is a huge effort, so best refer to the source. In your case the function resolvers.openers.helpers.textopener() takes the place of the open_read_file callback. It can be found in data-tex.lua. Regards Philipp
I am getting this error: callback ’open_read_file’ is frozen
Why is it "frozen"? Can I "unfreeze it"?
André Caldas. ___________________________________________________________________________________ If your question is of interest to others as well, please add an entry to the Wiki!
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I am trying to redefine the ’open_read_file’ callback.
[...] direct callback access is disabled. There are usually some layers of abstraction on top of them, different ones for different callbacks. Mapping them all is a huge effort, so best refer to the source.
In your case the function resolvers.openers.helpers.textopener() takes the place of the open_read_file callback. It can be found in data-tex.lua.
Shall I simply do something like this? local function textopener(tag, filename, filehandle, coding) result = old_textopener(tag, filename, filehandle, coding) -- Do lots of things return result end resolvers.openers.helpers.textopener = textopener Thank you, André Caldas.
On 2-10-2012 02:30, Andre Caldas wrote:
I am trying to redefine the ’open_read_file’ callback.
[...] direct callback access is disabled. There are usually some layers of abstraction on top of them, different ones for different callbacks. Mapping them all is a huge effort, so best refer to the source.
In your case the function resolvers.openers.helpers.textopener() takes the place of the open_read_file callback. It can be found in data-tex.lua.
Shall I simply do something like this?
local function textopener(tag, filename, filehandle, coding) result = old_textopener(tag, filename, filehandle, coding) -- Do lots of things return result end
resolvers.openers.helpers.textopener = textopener
this is not the recommended way .. better do somethign like this: \starttext \startluacode function document.MyCharacterMess(str,filename) if file.nameonly(filename) == "ward" then str = table.concat(string.totable(str,"."), " + ") end return str end local textfileactions = resolvers.openers.helpers.textfileactions utilities.sequencers.appendaction(textfileactions,"system","document.MyCharacterMess") \stopluacode \input ward \input knuth \stoptext ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------
Hello, Hans!
Shall I simply do something like this?
[...]
this is not the recommended way .. better do somethign like this: [...] function document.MyCharacterMess(str,filename)
Loved your function naming! :-) What is this "str"?
if file.nameonly(filename) == "ward" then str = table.concat(string.totable(str,"."), " + ")
What is this doing?
[...] utilities.sequencers.appendaction(textfileactions, "system","document.MyCharacterMess")
Why is "document.MyCharacterMess" a string? Isn't it less error-prone to use the function itself, instead of its name? Sorry for my naive basic questions... :-) Cheers, André Caldas.
Hello, Andre! Andre Caldas wrote:
function document.MyCharacterMess(str,filename)
What is this "str"?
This is a function that takes two variables; the first one it calls 'str', the second one 'filename'. Example: function f(a, b) return a/b end function(8,2) --> 4, not 0.25 I do not know what sort of str and filename are being passed to document.MyCharacterMess. (To all the action functions in utilities.sequencers.appendaction, in fact).
if file.nameonly(filename) == "ward" then str = table.concat(string.totable(str,"."), " + ")
What is this doing?
file.nameonly strips path and extenstion, e.g. file.nameonly('a/b/cod.doc') returns 'cod'. You can see the file.* functions in l-file.lua. string.totable splits a string, and returns the pieces as an array. In this case, the string is split at the periods. table.concat combines a table into a string, optionally putting a string (" + ", in this case) where the pieces join. so the `str = ...` line turns "Hello. I am Sam. You are also Sam." into "Hello + I am Sam + You are also Sam" or "hello.txt" into "hello + txt"
Why is "document.MyCharacterMess" a string? Isn't it less error-prone to use the function itself, instead of its name?
No idea. Cheers, and good luck, Sietse
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function document.MyCharacterMess(str,filename)
What is this "str"?
The raw file content as a Lua string. You can examine the arguments you get like so: ······································································· \startluacode document.arg_test = function (s, ...) table.print({...}, "file_content") return s end local textfileactions = resolvers.openers.helpers.textfileactions utilities.sequencers.appendaction(textfileactions,"system","document.arg_test") \stopluacode \starttext \input ward \input knuth \stoptext ·······································································
if file.nameonly(filename) == "ward" then str = table.concat(string.totable(str,"."), " + ")
What is this doing?
Split the input at every byte and re-concatenate using "+" as delimiter. (It’s a bit confusing as string.totable() takes only one argument ;-) )
[...] utilities.sequencers.appendaction(textfileactions, "system","document.MyCharacterMess")
Why is "document.MyCharacterMess" a string?
The sequencers use loadstring() internally (util-seq.lua), so you need to supply the namespace as a string. This happens all over the place with action/callbacks. Regards Philipp
On 2-10-2012 14:13, Philipp Gesang wrote:
Why is "document.MyCharacterMess" a string?
The sequencers use loadstring() internally (util-seq.lua), so you need to supply the namespace as a string. This happens all over the place with action/callbacks.
more flexible this way (one can redefine, nil or whatever such functions) ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------
Why is "document.MyCharacterMess" a string?
The sequencers use loadstring() internally (util-seq.lua), so you need to supply the namespace as a string. This happens all over the place with action/callbacks.
more flexible this way (one can redefine, nil or whatever such functions)
It is like a "pointer to a pointer". Or a reference to a reference, since we do not use pointers in Lua.
I am trying to redefine the ’open_read_file’ callback.
[...] utilities.sequencers.appendaction(textfileactions, "system","document.MyCharacterMess")
All I want is to get the full path (or path relative to lfs.currentdir()). Is "textfileactions" the action I should trap? Also, shall I use "after" or "before" instead of "system"? Since it is a module, probably I should use "system", right? Just want to be sure... Thank you all! André Caldas.
Am 02.10.2012 um 13:41 schrieb Andre Caldas
I am trying to redefine the ’open_read_file’ callback.
[...] utilities.sequencers.appendaction(textfileactions, "system","document.MyCharacterMess")
All I want is to get the full path (or path relative to lfs.currentdir()). Is "textfileactions" the action I should trap?
\starttext \startluacode function document.MyCharacterMess(str,filename) local path = "Path: " .. file.dirname(filename) local text = "Text: " .. str return table.concat({path,text},"\n\n") end local textfileactions = resolvers.openers.helpers.textfileactions utilities.sequencers.appendaction(textfileactions,"system","document.MyCharacterMess") \stopluacode \input ward \stoptext Wolfgang
On 2-10-2012 13:41, Andre Caldas wrote:
I am trying to redefine the ’open_read_file’ callback.
[...] utilities.sequencers.appendaction(textfileactions, "system","document.MyCharacterMess")
All I want is to get the full path (or path relative to lfs.currentdir()). Is "textfileactions" the action I should trap?
Also, shall I use "after" or "before" instead of "system"? Since it is a module, probably I should use "system", right? Just want to be sure...
\startluacode resolvers.installinputfilehandler("before",function(str,filename,...) logs.report(string.format("path: %s",file.dirname(filename))) return str, filename, ... end) \stopluacode ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------
On 1-10-2012 21:11, Andre Caldas wrote:
Hello!
I am trying to redefine the ’open_read_file’ callback.
I am getting this error: callback ’open_read_file’ is frozen
Why is it "frozen"? Can I "unfreeze it"?
because it's the only way we can guarantee some features working well (but one can plug in additional code before/after the built-in filters) Hans ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | voip: 087 875 68 74 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------
participants (5)
-
Andre Caldas -
Hans Hagen -
Philipp Gesang -
Sietse Brouwer -
Wolfgang Schuster