Difference between revisions of "Tutorials:SWORD 103"
David Haslam (talk | contribs) (Copied from email, lightly edited) |
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== The anatomy of an SWFilter == | == The anatomy of an SWFilter == | ||
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At the most basic level, a SWORD filter performs some distinct and | At the most basic level, a SWORD filter performs some distinct and | ||
concise transformation to the data stream. | concise transformation to the data stream. | ||
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The actual signature of a filter is very minimal, and looking at the | The actual signature of a filter is very minimal, and looking at the | ||
SWFilter interface itself... | SWFilter interface itself... | ||
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http://crosswire.org/svn/sword/trunk/include/swfilter.h | http://crosswire.org/svn/sword/trunk/include/swfilter.h | ||
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... there is simply 1 method you need to implemented to create a filter: | ... there is simply 1 method you need to implemented to create a filter: | ||
| − | char SWFilter::processText( | + | <pre>char SWFilter::processText( |
SWBuf &text, | SWBuf &text, | ||
const SWKey *key = 0, | const SWKey *key = 0, | ||
const SWModule *module = 0) = 0; | const SWModule *module = 0) = 0; | ||
| − | + | </pre> | |
Basically, you're sent a buffer of text, possibly along with some | Basically, you're sent a buffer of text, possibly along with some | ||
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into tiny manageable chunks that anyone can tackle. | into tiny manageable chunks that anyone can tackle. | ||
| − | "Handle <title> tags in a buffer? Sure, I can do that! That's easy.... | + | "Handle <title> tags in a buffer? Sure, I can do that! That's easy.... Wait.... What should I _DO_ with a <title> tag?" |
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That's when the real world hits and things get more complex. A SWORD | That's when the real world hits and things get more complex. A SWORD | ||
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distinct roles they are expected to fill, when, and in what order-- is | distinct roles they are expected to fill, when, and in what order-- is | ||
hidden knowledge that for years only few have been privy to yield... | hidden knowledge that for years only few have been privy to yield... | ||
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Stay tuned for "The Red Pill" coming soon to a listserv near you. | Stay tuned for "The Red Pill" coming soon to a listserv near you. | ||
Revision as of 19:35, 3 December 2010
The anatomy of an SWFilter
At the most basic level, a SWORD filter performs some distinct and concise transformation to the data stream.
The actual signature of a filter is very minimal, and looking at the SWFilter interface itself... http://crosswire.org/svn/sword/trunk/include/swfilter.h
... there is simply 1 method you need to implemented to create a filter:
char SWFilter::processText(
SWBuf &text,
const SWKey *key = 0,
const SWModule *module = 0) = 0;
Basically, you're sent a buffer of text, possibly along with some context in the form of an SWKey and SWModule-- in case you care, and then you make some small change to the buffer.
Easy, right? Well, sortof.
Anyone can write a filter. The great thing about filters is that they partition up a very complicated task: processing a complex document, into tiny manageable chunks that anyone can tackle.
"Handle <title> tags in a buffer? Sure, I can do that! That's easy.... Wait.... What should I _DO_ with a <title> tag?"
That's when the real world hits and things get more complex. A SWORD filter is an easy to grasp, easy to code against, abstract concept.
How filters are orchestrated together inside the SWORD engine-- what distinct roles they are expected to fill, when, and in what order-- is hidden knowledge that for years only few have been privy to yield...
Stay tuned for "The Red Pill" coming soon to a listserv near you.
