World: r3wp
[Core] Discuss core issues
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Janko 21-Jan-2010 [15548x2] | Maybe something related .. why google is using Lua : http://google-opensource.blogspot.com/2010/01/love-for-luajit.html http://article.gmane.org/gmane.comp.lang.lua.general/62321 >>Our Lua usage isn't too widespread at the moment; it's really one infrastructure project in particular that uses Lua to allow user-defined functions to run within a tightly controlled container. Lua was the best choice, because of its low overhead, fast execution, and the ability to set limits on execution time.<< |
hm.. basically I see now where my inspiration came from to finally started nagging about this today :)) | |
BrianH 21-Jan-2010 [15550] | Lua was designed as an extension language, not a general-purpose language. |
Janko 21-Jan-2010 [15551x3] | basically they mention exactly what we are talking about now. also about what you mention "execution limits" |
yes, I know.. but those abilities only make it stronger not weaker at the end (it also has some form of sandboxing it seems): http://lua-users.org/wiki/SandBoxes | |
the fact that R3 will be embeddable inside c apps is a HUGE plus in my view too | |
BrianH 21-Jan-2010 [15554] | They make it stronger at a different field of endeavor. We can borrow ideas from Lua for those occasions where we are performing Lua-like tasks, especially to make extension language dialects. |
Janko 21-Jan-2010 [15555] | I embedded lua and nekovm when I was working at some game to make levels scriptable instead of data driven. It was really nice way to make games, and if I could I would much rather use rebol. rebol is the data and dialect language which is main point of embedding dynamic languages in the first place |
BrianH 21-Jan-2010 [15556] | And these embedded dialects could even resemble a subset of the DO dialect. |
Janko 21-Jan-2010 [15557x4] | I really like lua, I would most probably be using it if it weren't for rebol which still have even more reasons to use it |
cool | |
BrianH: while I have you here :)) .. is there any chance to have a curry word in rebol >> format-money "$" 10000 "" "," "." ; args are: before number after 1000-separator dec-separator >> format-money "$" 4500 "" "," "." >> my-format: curry format-money [ "$" _ "" "," "." ] >> my-format 10000 >> my-format 4500 | |
maybe I will try to hack it in R2 some day.. but it probably won't be very effective | |
BrianH 21-Jan-2010 [15561] | Try using APPLY in a generated wrapper function. |
Janko 21-Jan-2010 [15562] | I will thanks |
BrianH 21-Jan-2010 [15563x2] | It will be a little tricky if you want to support get-word and lit-word parameters. It might be at the same scale as APPLY in R2. See the source of APPLY for details. |
In any case it would be a *lot* slower than making wrapper functions. | |
Janko 21-Jan-2010 [15565] | aha, then it's maybe not that usefull.. I have wrapper function right now for this case... basically I have a closure money-format-maker |
BrianH 21-Jan-2010 [15566x2] | Take a look at the new functions in 2.7.7, particularly APPLY and CLOSURE. |
I'm still hoping to make an IT function in R3 though :) | |
Janko 21-Jan-2010 [15568] | I will :) .. what is IT ? like the last thing on stack maybe? |
BrianH 21-Jan-2010 [15569x2] | REBOL doesn't use a stack machine. IT was a proposal for a function to return the result of the conditional expression of the nearest enclosing conditional function, basically IF or UNLESS. If we can add CASE support too that would be amazing, but it's unlikely without IF being native. As it is a mezzanine IF function would need debug privileges. |
a mezzanine IF function -> a mezzanine IT function | |
Davide 21-Jan-2010 [15571] | What about a "pipe" operator (as in F#), such that you can write something like: read/lines %files | remove-each x [10 > length? x] | sort Would be simplier to read than: sort remove-each x read %file [10> length? x] Basically the pipe gives the parameter to the following function that is of the same type of the function that precede it. BTW I think that this could be done with a dialect |
BrianH 21-Jan-2010 [15572x2] | REMOVE-EACH has 3 parameters. |
To know which parameter to pass along you'd need a dialect with a list of supported functions in its code. | |
Davide 21-Jan-2010 [15574x2] | yes, the second parameter is given by the pipe |
but you can see the type of the parameter | |
BrianH 21-Jan-2010 [15576] | And how would the pipe know to send to the second parameter, when the first and third also allow block parameters? REMOVE-EACH is just another function - the meaning of its parameters is specific to that function. |
Davide 21-Jan-2010 [15577] | isn't the first parameter of remove-each a word ? |
BrianH 21-Jan-2010 [15578x2] | There's a lot of tricks that you can do with compiled languages with fixed function definitions that you can't do as easily in REBOL without whole program analysis. |
>> spec-of :remove-each == [ {Removes values for each block that returns true. Returns remove count. (Modifies)} 'word [word! block!] "Word or block of words to set each time (local)" data [series!] "The series to traverse" body [block!] "Block to evaluate (return TRUE to remove)" ] | |
Davide 21-Jan-2010 [15580] | ops, wrong example ;-) |
BrianH 21-Jan-2010 [15581] | It just happens that that function value is assigned to that word. With the next call of the piped code it might be a different function. |
Janko 21-Jan-2010 [15582x2] | hehe, this is exactly where curry would be needed :)) read/lines %files | curry remove-each [ x _ [10 > length? x] ] | sort |
for functions that take just one example you can make it yourself pretty simpy.. I made it last week for processing tome fixed width data file .. | |
BrianH 21-Jan-2010 [15584x2] | People say "do it in a dialect" like those come for free. There's dialect processing overhead, issues of when the arguments are processed, decisions about whether there are keywords or not. To get an idea about the real overhead of doing it in a dialect, look at the source of APPLY or MAP-EACH in R2. Both are compiled dialects. |
If there's any way to make your code execute in one of the native dialects, do it, it's worth it. | |
Janko 21-Jan-2010 [15586] | data: parse-fixed-width-lines read/lines %PO.txt [ vat-incl: 4 [ trim empty? not ] vat-num: 9 trim ... ] this func is used to execute [ trim empty? not ] with a value.. which is similar to pipe or stack lang with only 1 level deep stack :)) stream-through: func [ fs d /local x acc ] [ accumulate x acc copy [] fs [ do compose [ (x) d ] ] ] |
Gregg 23-Jan-2010 [15587] | Janko, Ladislav did the most extensive CURRY I know of, though Joel Neely also did one, and a number of us have rolled simple versions here and there. http://www.fm.tul.cz/~ladislav/rebol/curry.r |
Henrik 23-Jan-2010 [15588x2] | Is there any solid way to find which chars are illegal in a specific file system? |
Never mind. Using some tables here. | |
Geomol 23-Jan-2010 [15590] | Henrik, I've used info here: http://en.wikipedia.org/wiki/Filename Do you have better info? |
Henrik 23-Jan-2010 [15591x2] | http://support.grouplogic.com/?p=1607 I used this one. |
but I see yours is better | |
Terry 23-Jan-2010 [15593x2] | Any gotchas when posting xml via read/cutom [post "<my xml>"] ? |
I'm getting a "REST method is not defined" response. | |
Maxim 23-Jan-2010 [15595] | that will depend how the server wants the post data... |
Terry 23-Jan-2010 [15596] | maybe some kind of REST header needs to be sent as well? |
Maxim 23-Jan-2010 [15597] | not an expert on REST interfaces... though I am using one with a server right now... |
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