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[REBOL] Re: REBOL Newbie tries to convert C source to REBOL (long posting)

From: tomc:darkwing:uoregon at: 20-Nov-2003 21:20

response on bottom On Thu, 20 Nov 2003, Mike Loolard wrote:
> Hi everybody ! > > I am currently trying to port an ANSI C application over to REBOL. > I am pretty much a newbie to REBOL - and was pretty impressed by > its capabilities. > > My problem now is, porting looked a lot easier than it actually turns out to > be for me. > > I seem to lack some fundamental things in REBOL - maybe I just think too > "one-dimensional" > because of my ASM/C - background, indeed, in C I do parse the whole data > BYTE by BYTE - something that > doesn't seem effective with REBOL - as there seem to be more efficient > methods available, > as I understand it. > > Actually, I would think the application should be fairly easy to > be implemented with REBOL - it's bascially only 'simple' string processing - > > not much more. That's why I thought I should give it a try - also to be able > to compare REBOL performance with my compiled C-application. > > basically, this is what my C source does: > > 1) open a data file (approx. 1 MB data) > > filename: "test.dat" > data: read filename > > 2) parse the file for sections - every section is indicated by square > brackets > and is valid to the next (new) section > > like this: (example data) > -------------------------------------------- > [sec1] > dataline1 111.11 N012.11.029 E034.31.110 > dataline2 131.11 N012.11.099 E034.31.110 > dataline3 111.11 N015.11.099 E034.31.110 > > [sec2] > datalinex HFD 111.11 N012.11.099 E034.31.114 > dataliney LKA 131.41 N011.11.049 E031.31.116 > datalinez JIH 111.11 N012.11.019 E032.31.114 > -------------------------------------------- > So each sections contains several hundreds of lines with data, > the data syntax is different with each section. That's why I initially > separate the data only by whitespaces in C and take care of the exact syntax > at > a later time, using parsing rules specified in another array. > > 3) In C I would now simply determine each section's offsets within the > memory > and then store (memcpy) each section into its own multi-dimensional array > using the offsets > I determined in the previous loop, where each line of data is directly > accessible > - but also every part of the data line (separated by whitespaces). > > At first I would go and compute every section's beginning like this: > ________________________________________ > sections: make block! 40 > > parse data [ > any [to "[" copy sec indx: thru "]" > (append sections index? indx) > {/* > For debugging purposes I also emit the name of each section > that's found. > */} > (print sec) > ] > ] > ________________________________________ > > Then I got the position of each section in the data-series and compute > the offset of each section by calculating the difference between 2 adjacent > sections. > Accordingly, in C I would then go to extract/copy the data within the two > offsets > and put it all in another array to work with. > > That's exactly where my problems start to overwhelm me. > While reading the file in, and parsing it for sections does seem to > work fairly well (and with MUCH less code !), I am having difficulties to > create the > multi-dimensional arrays for each section where all data is individually > accessible stored. > > So as an example, having parsed [sec1] I want every element in each line to > be individually > accessible to simplify conversion. > > 4) Although the arrays don't work yet I tried to port the parsing routines > over - > In C I take the "parent" array that contains all sub-arrays and parse each > section individually. Parsing is done in C with a certain set of rules (also > stored in an array) > - using regular expressions, I 'expect' a certain data format for particular > sections. > If a rule is matched I parse with that rule and separate the data into > sub-arrays. > > In REBOL the latter seems fairly easy using the parse command: > > 5) when all data has been processed and separated by its corresponding rule > I need to > convert the data for each section into a different format. > With C I am again using regular expressions to implement conversion. That's > why I > stored the recognition-rule and the conversion-rule in the same array > > 6) Final conversion of the original data will be to CSV-format - including > most data that was > read, but occasionally not all data is needed or an abbreviated form is > sufficient. > > Maybe you guys got some thoughts on my problem - I don't want/need actual > code - rather some > hints how to accomplish my goals in REBOL. As you may be able to tell from > the way I describe > the problem, I might indeed be too heavily thinking in C. By the way: are > you aware of any > tutorials or books, particularly targeted at C-programmers. This seems > really to be a situation > where previous programming-experience limits my way of thinking. I did read > a lot of stuff on > the REBOL webpages, but still do have problems, grasping the inner concepts > within in REBOL. > > Another question that just came to my mind: is there any decent REBOL code > editor available? > Simple syntax highlighting would be one thing - but I am thinking more of a > supportive > editor that also supports syntax completion or smart tooltips, helping a > newbie like me. > > I guess, the power of REBOL is also some kind of problem for such an editor, > as single > objects/words can mean different things and dialects can easily be extended. > Maybe some really good REBOL-programmer should go and program an editor > for REBOL IN REBOL (view) ;-) > > I'd really love to see a REBOL-editor being implemented in REBOL - it could > easily be > enhanced by everybody, there might even be some kind of "plugin" concept > considered - > using rebol scripts, that are executed on demand. > Using REBOL/VIEW it would also be available on pretty much all platforms. > > Thanks for any help and comments - and sorry for this rather long eMail ;-) > > P.S.: Is there any kind of REBOL-specific FORUM available on the web ? If > not: why not ? I would be willing to > create one - if there's demand. > > -- > regards > > _________________ > --------- > Mike > > GMX Weihnachts-Special: Seychellen-Traumreise zu gewinnen! > > Rentier entlaufen. Finden Sie Rudolph! Als Belohnung winken > tolle Preise. > > +++ GMX - die erste Adresse für Mail, Message, More! +++ > > -- > To unsubscribe from this list, just send an email to > [rebol-request--rebol--com] with unsubscribe as the subject. >
hopefuly this will get your mind moving slightly differently data: { [sec1] dataline1 111.11 N012.11.029 E034.31.110 dataline2 131.11 N012.11.099 E034.31.110 dataline3 111.11 N015.11.099 E034.31.110 [sec2] datalinex HFD 111.11 N012.11.099 E034.31.114 dataliney LKA 131.41 N011.11.049 E031.31.116 datalinez JIH 111.11 N012.11.019 E032.31.114 } sections: make block! 40 row-data: complement charset "[^/" ; accept any char not \[ nor \n row: [copy r some row-data newline ; break section into rows by \n (insert/only tail blk parse r none) ; break row into fields by ws ] parse data [ some [ to "[" copy sec [thru "]"] (print sec) thru newline ; well you are all ready here so... ; instead of storing the location and all that ... ; just deal with it now. (insert/only tail sections blk: make block! 500) any row ] ] ; to see what native types rebol would see in each field foreach sec sections[ foreach row sec[ foreach field row[ prin [type? load field field " " ] ] print "" ] ] ;probe sections