Hi Eric, Great write-up!
When I first started TW, I wrote an application or two using the Data plugin, mainly because the information about programming slices/ sections was less accessible (vi tiddlywiki.org) than information from the author's site about the Data plugin. If I re-wrote them now, I would probably tend to use slices/sections. Your example demonstrates how to pull and used slice/section data programmatically. But what if I want to push data back into a tiddler (e.g., change "Name: Rowling" to "Name: Pratchett" ? Or change something like: !Latest Book Nation to !Latest Book Unseen Academicals Is there some simple code to accomplish this, or would I have to essentially replace the entire original Tiddler contents? Thanks! Mark On Oct 10, 11:14 pm, Eric Shulman <[email protected]> wrote: > On Oct 10, 6:22 pm, AlanBCohen <[email protected]> wrote: > > > I've been trying to fully understand the ways you can record, edit, > > and retrieve structured data in a TW. So far, I see the following as > > the options: > > "Slices" and "Sections" > ---------------------------------- > > Tiddler slices and tiddler sections are TW native methods of storing > *named* data values by entering information within the normal text of > a tiddler, surrounded by specific patterns of wiki-syntax formatting. > > Because they are part of the regular tiddler content, it is easy for > users to add or update information stored in slices or sections, > without having to create any special input or display handling. > > A slice is a simple name/value pair, specified using a 2-column TW > table, like this: > > |slicename1|slicevalue| > |slicename2|slicevalue| > (e.g. at the top of published plugins, scripts, etc.) > > or, using a 'description' syntax, like this: > slicename1: slicevalue > slicename2: slicevalue > (e.g., the default shadow ColorPalette definition) > > Regardless of which syntax you use, each slicename should be unique to > the tiddler in which it is defined. Slice values are intended to hold > relatively short bits of text, and cannot contain any newlines. > Fortunately, when you need to store larger, multi-line blocks of text, > the tiddler *section* syntax is available. > > A section begins with the TW 'heading' syntax, ! through !!!!!!, where > the heading text is used as the section name, and the value of the > section is everything following the heading, up until the next heading > (of any level), or the end of the tiddler, whichever is reached > first. Thus: > !SectionName > This content is on > multiple lines > !NextSectionName > This is a different section > with more lines of content > !AnotherSectionName > etc. > > Once they are stored within the tiddler text, you can easily embed the > value of any given slice or section into another tiddler, by using the > standard <<tiddler ...>> macro, with a special syntax for referring to > slices or sections, like this: > <<tiddler SomeTiddler::SliceName>> > <<tiddler SomeTiddler##SectionName>> > Note: As with any tiddlername used in a macro, if the slice or section > name contains spaces, you will need to enclose the reference in > brackets: > <<tiddler [[SomeTiddler::Slice Name with spaces]]>> > <<tiddler [[SomeTiddler##SectionName with spaces]]>> > As a general rule-of-thumb, when possible, avoid using long text with > spaces when defining slices and section names... it's just easier that > way. > > If you enclose your slice tables or sections within TW comment markers > (/%...%/), then they will not be *rendered* when the tiddler is > displayed, but will still be accessible as named slice or section data > using the <<tiddler>> macro as described above. These are called > "hidden slices" and "hidden sections", and can be used to store > 'variables' associated with the tiddler, without affecting the > rendered appearance of that tiddler. > > When definining a hidden section, it can be helpful to ensure that it > has a specific beginning *and* ending by adding a 'junk' heading > following the section content, like this: > /% > !SectionName > This is content > !end > > !OtherSection > More content > !end > %/ > > Note the "!end" heading is repeated multiple times in the same > tiddler. The "!end" simply serves to mark the ending of each hidden > section. This is OK, as long as we don't actually try to retrieve a > *value* from the "!end" section... and, since the entire block of > content is *hidden*, it doesn't matter how many times "!end" is used, > as it is never actually displayed. > > To get the value of a slice or section *programatically* (i.e., for > use with <<forEachTiddler>>, InlineJavascriptPlugin, or when writing > actual plugin code), you can use the TW standard function: > var txt=store.getTiddlerText("TiddlerName::slicename") > var txt=store.getTiddlerText(""TiddlerName##sectionname) > > Of course, not every tiddler in a document will have the same slice > and/or section definitions (if any). While it is possible to query > each tiddler in turn to determine if a given slice/section is present, > it is often more useful to determine the kind of information stored in > a tiddler's slices/sections by tagging the tiddler with some pre- > determined value that desigates it's "type". > > Then, you can use that tag value to 'filter' the list of tiddlers to > be retrieved, so that only those with the desired slices and/or > sections are processed. > > For example, here's an inline script that gathers up information about > 'bookmark' tiddlers, and outputs a summary, formatted as an "HR- > separated list" > > <script> > var out=[]; > var tids=store.getTaggedTiddlers("bookmark"); > for (var i=0; i<tids.length; i++) { > var t=tids[i].title; > var d=store.getTiddlerText(t+"::Description"); > var u=store.getTiddlerText(t+"::URL") > out.push("[[%0]] - %1\n%2".format([t,d,u]));} > > return out.join("\n----\n"); > </script> > > Hopefully, this should be enough to get you started with slices and > sections... > > enjoy, > -e > Eric Shulman > TiddlyTools / ELS Design Studios --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "TiddlyWiki" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/tiddlywiki?hl=en -~----------~----~----~----~------~----~------~--~---
