Path: usenet.cise.ufl.edu!newsfeeds.nerdc.ufl.edu!news.magicnet.net!news.maxwell.syr.edu!netnews.com!news-b.ais.net!ais.net!uunet!in1.uu.net!news.neta.com!not-for-mail From: Martin Schwartz Newsgroups: comp.lang.perl.announce,comp.lang.perl.modules Subject: Announce: Convert::Context Followup-To: comp.lang.perl.modules Date: 6 Oct 1998 15:21:32 GMT Organization: Technical University of Berlin, Germany Lines: 245 Approved: merlyn@stonehenge.com (comp.lang.perl.announce) Message-ID: <6vdchs$bl0$1@news.neta.com> NNTP-Posting-Host: gadget.cscaper.com X-Trace: news.neta.com 907687292 11936 206.67.186.3 (6 Oct 1998 15:21:32 GMT) X-Complaints-To: abuse@neta.com NNTP-Posting-Date: 6 Oct 1998 15:21:32 GMT X-Disclaimer: The "Approved" header verifies header information for article transmission and does not imply approval of content. Xref: usenet.cise.ufl.edu comp.lang.perl.announce:153 comp.lang.perl.modules:4643 Hi, As part of a larger work I wrote a module dealing with Attributed Strings. It adapts perl's string commands, so the usage should flow easily into your mind. I called it Convert::Context. Convert, because I assumed it to be the typical environment where this module will be used. Context, because it deals with connotated Texts. Ok, the name is negotiable. ;) The module might be interesting for all persons dealing with texts having format tags or other stuff mixed among. Think of HTML, XML, WordPerfect. Current state might be characterized as "working but not optimized". So here comes Convert::Context. An excerpt of the man page follows below. The distribution file is called: Convert-Context-0.500.tar.gz I just put it into my CPAN directory. You can get it also directly from: http://wwwwbs.cs.tu-berlin.de/~schwartz/perl/ Have fun, Martin === schnipp NAME Convert::Context - an Attributed Text data type - ALPHA - release SYNOPSIS See below. DESCRIPTION Convert::Context maintains attributed strings. It allows you to access those strings similar to perl's normal strings. An attributed string is a string to that attributes are connected at certain string positions. An attribute can be everything scalar: numbers, strings, references are welcome. Attributes are not part of the string. Semantics of the attributes have to be done by the applying code. What does this mean? A basic work for a text system is to localize a certain text part. This is trivial if you have only plain text to look at. It is no longer trivial, if you have attributes or entries among your text like: bold, italic, bookmarks and so on. One has two strategies to mingle attributes with a string: 1. You can enrich the text by inserting control codes. E.g., if you have a line with two bold words: (A) "The word bold is always bold" it would look (here with HTML controls) like: (B) "The word bold is always bold" If you would look for the text "bold is" in (B) with perls m// operator, you'd fail. You would have to strip the HTML control sequences first. This is an ok method, but not used here. 2. You can maintain separate lists, holding at which position of the text which control codes are stored. This is, what Convert::Context does. The example from above would look like: offset 0---------1---------2------- text The word bold is always bold attrib (0 1 0 1 ) [...] new $Ct = Convert::Context -> new ( [$cs] ) $Ct = Convert::Context -> new ( [$cs,] \$txt [,[@a], [@o]] ) $Ct = Convert::Context -> new ( [$cs,] [\$txt [,[@a], [@o]]], [...], ... ) Returns a new Context string. It can be initialized three ways: (1) Without parameters, (2) with a reference to a text string, an attrib list reference and an offset list reference, or (3) with a list of references of (2). Optionally it can be initialized with a leading parameter $cs. This stands for "character length" and specifies the byte size of one character. One needs this when using e.g. UTF16 (Unicode) characters. Example: (1) $Empty = Convert::Context -> new; (2) $Plain = Convert::Context -> new (\("Plain text\n")); $Bold = Convert::Context -> new (\("Attribute 1 text"), [1]); (3) Special (but useful) case: $Mixed = Convert::Context -> new ( [\("This is an "), [0] ], [\("all bold"), [122] ], [\(", short and sometimes ") ], [\("italic"), ["Strange text attribute"] ], [\(" text." ] ; Attribute 0 and Offset 0 is used as default value, if none is explicitly given. The meaning of all attributes (here 0, 122 and "Strange text attribute") has to be defined 100% by the applying code. In this example one would assume, that a text processor was connoting the attributes 0, 122 and "Strange text attribute" to the semantics: plain, bold and italic. replace $n = $Ct -> replace ($pattern, $replace, egimosx) Replaces one or all occurrances matching to $pattern with $replace. Returns the number of replacements, or false if pattern is not found. Implemented mainly via perls replace operator: s/$pattern/$replace/egimosx $replace here can be a string, a Context or a code reference. In the latter case this routine will be called at each match, passing the matched string as parameter. The matched text will then be replaced with the return value of the routine. $n = $Ct -> replace ([@pattern], [@replace], egimosx) You can call replace with list references holding corresponding sets of patterns and replacements. pattern and replace can be strings or Contexts, and replace additionally code references. The patterns will be glued together to a single pattern match, using pattern match or operator |. Examples: (1) $Ct -> replace ("krims", "kram", "g") Option g says, that not only one, but all occurrances of string "krims" shall be substituted by string "kram". "kram" will get the attributes of "krims" (see method "substr"). If you want to have more control about the attributes of "kram", you can pass the replacement string as a Context. (2) $Ct -> replace ("krims", $Ct, "g") Replaces all occurrances of string "krims" with the Context $Ct. This is useful, if you want to have $Ct special attributes. (3) $Ct -> replace (" asta tu ", " AStA TU ", "ig") Option i says, that the characters case shall be ignored. So example (3) would replace " asta tu ", " ASTA TU ", " Asta Tu " ... with " AStA TU ". (AStA stands for Allgemeiner Studierendenausschuss. Students governments are called like this in Germany and quite cool). (4) $Ct -> replace ("\02", \&footnote, "g") This would call a function "footnote". The function will be called with three parameters: &function($match, $Ct, $pos) 1. The matched string (here "\02") 2. The Context (here $Ct) 3. The match position (5) $Ct -> replace ("krims", sub {allow (@_, "kram")}, "ig") This notation would call a function "allow" for each match, quite like (4). But further more here the string "kram" would be passed as additional parameter. (6) $Ct -> replace (["a", "o"], ["o", "a"], "g") Substitutes a's with o's and o's with a's. [...] substr $Ct2 = $Ct1 -> substr ($o1, $l1) Returns a partial Context of Ct1 as new Context Ct2. Ct2 will be copied from Ct1 starting at position o1 and with the length l1. $Ct = $Ct -> substr ($o1, $l1, $str [,$o2, $l2]) If a string is given as argument, the partial Context starting at offset o1 with length l1 is substituted by string. String gets the attributes of the partial Context. If e.g. the string to be replaced would be "<0>di<1>n<2>g<0>s", after the replacement it might look like "<0>bu<1>m<2>s". $Ct1 = $Ct1 -> substr ($o1, $l1, $Ct2 [,$o2, $l2]) The partial Context of Ct1 starting at offset o1 with length l2 is substituted by Context Ct2. If o is undef, o is set to 0. If l is undef, l is set according to end of Ct [...] === schnapp -- // Le degre zero de l'ecriture? Zero probleme!