[REBOL] Re: REBOL Script to convert REBOL format to RSS XML
From: greggirwin:mindspring at: 30-Dec-2004 17:12
Hi Premshree,
PP> Anyway, I wrote a small script that generates valid RSS 2.0 feeds from
PP> the REBOL data for Carl's blog. The code is available here:
PP> http://premshree.seacrow.com/code/rebol/carl-rss.r/download
Very cool!
PP> If there are improvements possible, please point so/do so. :)
I did a quick re-hack of things, just to show you some different
approaches. Others may chime in with more thoughts as well. Some of
the things I thought about when evaluating your code:
* Use path notation instead of SELECT
* Don't use temporary vars if you don't need to
* Tags are a valid datatype, you don't need to make them strings
* JOIN (and REJOIN) build new strings, meaning lots of allocation
and work for the GC. INSERT, APPEND, and their ilk just add on
to an existing series; also saves reassigning the value.
* See what refinements date! values offer to see if you need to
convert them to strings to do what you want.
* REPEAT is faster than FOR if you're going from 1 and
incrementing by 1. FOREACH makes things even easier most times.
I did a couple more advanced things in there (note the tick on the
MAKE-ENTRY 'key parameter) and did some others to give you some things
to take apart and think about. Holler away if you have questions.
BTW, this was a very quick hack, so I don't know if, for example,
TO-IDATE gives a valid format as far as RSS is concerned.
-- Gregg
REBOL [
Title: "RSS Generator for Carl's Blog"
Date: 31-Dec-2004
File: %carl-rss.r
Home: http://www.livejournal.com/~premshree
Author: ["Premshree Pillai" "Gregg Irwin"]
Version: 0.0.2
Purpose: {
Generates valid RSS 2.0 feeds for Carl's blogs
}
Comment: {
Massive code changes for instructional purposes. --Gregg
}
]
;; channel data
channel: [
title "Carl's REBOL Blog - Vive la REBOLution"
link http://www.rebol.net/
description "describes this blog channel"
language "en" ;"English"
copyright "2005 Carl Sassenrath"
generator "REBOL Messaging Language"
]
;; blog items go here
items: [
[
title "Blog item title...."
link http://www.rebol.net/cgi-bin/blog.r?view=0080
author "Carl Sassenrath"
pubdate 30-Dec-2004/0:0:0
content {the blog goes here}
]
[
title "Blog item title 2...."
link http://www.rebol.net/cgi-bin/blog.r?view=0081
author "Carl Sassenrath"
pubdate 31-Dec-2004/0:0:0
content {the blog 2 goes here}
]
]
;-- No Changes needed below this point -------------------------
make-entry: func [series 'key] [
rejoin [tab to tag! :key series/:key to tag! join #"/" :key]
]
channel-entry: func ['key] [make-entry channel :key]
channel-entries: func [keys [block!] /local result] [
result: copy ""
foreach key keys [append result join channel-entry :key newline]
result
]
output: copy ""
repend output [
<?xml version='1.0' encoding='utf-8' ?> <rss version='2.0'> newline
<channel> newline
channel-entries [title link description language copyright generator]
]
foreach item items [
repend output [
tab <item> newline
tab tab <guid isPermaLink='true'> item/link </guid> newline
tab tab <pubDate> to-idate item/pubdate </pubDate> newline
tab tab <title> item/title </title> newline
tab tab <link> item/link </link> newline
tab tab <description> item/content </description> newline
tab </item> newline
]
]
repend output [</channel> newline </rss>]
;print output
;halt
write %carl-rss2.xml output