World: r3wp
[Parse] Discussion of PARSE dialect
older newer | first last |
Sunanda 12-Jan-2006 [830] | No....I suspect they each have core abilities they excel and other things they can only do with ugly workarounds, if at all. It'd be interesting to see experts bringing out the best in both. |
Gregg 12-Jan-2006 [831] | There was some talk about that on the ML a few years back. Joel and Ladislav had some great exchanges IIRC. Parse and RegEx are different tools. I can see the power of RegExs, but they aren't for the faint of heart when you start doing complex things. A RegEx can be very concise, and can be very handy for simple pattern matching. |
Ladislav 13-Jan-2006 [832] | http://www.compkarori.com/vanilla/display/PARSE-Versus-Regexs |
Gregg 13-Jan-2006 [833] | Thanks Ladislav! |
Rebolek 1-Mar-2006 [834] | Is it possible to use "<" ">" and so on in parse rules? (not in string parse). |
Anton 1-Mar-2006 [835x2] | What are you trying to parse ? |
I think the answer is no, but I am not sure of the question yet. Please give an example input. | |
Rebolek 1-Mar-2006 [837x3] | I'm trying to parse something as simple as 1 < 2. |
hm it's possible with any-word! ... | |
but that does not help me very much | |
Anton 1-Mar-2006 [840] | Yes, I'm not having much luck here. |
Rebolek 1-Mar-2006 [841] | Probably it's something like Oldes' comma problem. :/ |
Gabriele 1-Mar-2006 [842] | >> lt: to lit-word! first [ < ] == '< >> parse [1 < 2] [number! lt number!] == true |
Rebolek 1-Mar-2006 [843x3] | great, thanks! |
actually not great, but working :) | |
Unfortunately, there's probably no similar trick that can be used with comma, poor Oldes | |
Volker 1-Mar-2006 [846] | replace/all str "," comma " ; :)) |
Oldes 1-Mar-2006 [847] | you cannot use this in a dialect! |
Volker 1-Mar-2006 [848] | before i load the string! But not too reliable, if you have "," in strings. |
Oldes 1-Mar-2006 [849] | and I'm not such a poor:-) I am using double parenthesis in my dialect instead of using commas (it's ugly, but it's working) |
Volker 1-Mar-2006 [850] | how does some sample code look? |
Oldes 1-Mar-2006 [851x2] | I still think it's a shame, that we cannot load strings with commas, so we cannot forexample parse javascript or actionscript |
my code looks like doSomeFunction(("a" add b) 1) | |
Volker 1-Mar-2006 [853] | i think that is hard to do perfectly. for example "\"", how to parse that? |
Oldes 1-Mar-2006 [854] | in actionscript it's doSomeFunction("a" add b, 1) |
Volker 1-Mar-2006 [855] | doSomeFunction("a" add b # 1) doSomeFunction("a" add b . 1) ? |
Oldes 1-Mar-2006 [856x2] | I know it woud be possible to improve my dialect, but I'm not going to do it in near future, I'm already used to write it this way:) |
I think it's quite logical to close it in parenthesis than using chars like # | |
Volker 1-Mar-2006 [858] | But chars like # are easier to search/replace. But i dont defend my solution, yours looks ok. Do you write your dialect-code in rebol-blocks or in a string? |
Oldes 1-Mar-2006 [859x4] | And for the Rebolek: I use in RSWF this: |
slash: to-lit-word first [/] dslash: to-lit-word "//" rShift: to-lit-word ">>" UrShift: to-lit-word ">>>" _bigger: to-lit-word ">" _less: to-lit-word "<" _noteql: to-lit-word "<>" _lesseql: to-lit-word "<=" _biggeql: to-lit-word ">=" | |
and then: | |
'* (term-op: [ins-act #{0C}]) | slash (term-op: [ins-act #{0D}]) ;Divide | dslash (term-op: [ins-act #{3F}]) ;Modulo | rShift (term-op: [ins-act #{64}]) ;RShift | UrShift (term-op: [ins-act #{65}]);UnsignedRShift | lShift (term-op: [ins-act #{63}]) ;lShift | '| (term-op: [ins-act #{61}]) ;bitwise OR | ['|| | 'or] (term-op: [ins-act #{11}]);OR | ['& | 'band] (term-op: [ins-act #{60}]) ;bitwise AND | 'and (term-op: [ins-act #{10}]) ;AND | |
Rebolek 1-Mar-2006 [863] | Thanks Oldes, that should help me |
Oldes 1-Mar-2006 [864x2] | Volker: blocks |
it's much more easier as you can use Rebol's datatypes | |
Volker 1-Mar-2006 [866] | i thought about something like "js-load string" which would do the comma-conversion. But if your dialect works, no need for extra work. |
Rebolek 1-Mar-2006 [867] | maybe fixing REBOL should be better? If "." can work without problem, why not "," ? |
Volker 1-Mar-2006 [868] | interesting question why it is left out. but you would have other problems too, although not that often. like "\"". in rebol that is "\" " . in javascript "^"" |
Rebolek 1-Mar-2006 [869] | Volker this is some special case, you can replace that before parsing string, but you cannot replace all commas in action script, some of them may be parts of string |
Rondon 2-Mar-2006 [870x2] | Does anybody have an script to parse BNFs? |
BHF's specification.. | |
Gregg 3-Mar-2006 [872] | I think Bretty Handley did. Check codeconscious. |
Rebolek 5-Mar-2006 [873] | I think this should print 5 and return 'true. But it does not. >> parse [1 2 3 4 5][any number! set val number! (print val)] == false Help please? :) |
Anton 5-Mar-2006 [874x2] | >> parse [1 2 3 4 5][any [set val number!] (if value? 'val [print val])] 5 == true |
What you did was consume the five numbers, then try to set val to a sixth one. | |
Rebolek 5-Mar-2006 [876] | What I want is work with first four numbers and not with the last one |
Anton 5-Mar-2006 [877] | Is it always 5 numbers ? |
Rebolek 5-Mar-2006 [878] | No :( |
Anton 5-Mar-2006 [879] | >> parse [1 2 3 4 5][4 [set val number! (print val)] number!] 1 2 3 4 == true |
older newer | first last |