[REBOL] Re: Complex Series Parsing (Part 2)
From: sterling:rebol at: 9-Mar-2001 11:03
Well, before anybody goes further into the "here's something that
works for the last input you posted" followed by "but then there's
this input that doesn't work" path, lets go back to the definition of
input and output.
If you use load.markup and trat the REBOL words you have in your block
as strings like Andrew suggests (which is a better way to deal with
them), then you have these input elements:
* <text> -- open text tag
* "???" -- some arbitrary string
* <???> -- some other open tag
* </???> -- some close tag
* </text> -- a close text tag
Your input looks like this:
probe input: load/markup {<tag0></tag0> <text> this and that
<tag1>those </tag1>and > these</text><tag2></tag2><text>There and
then</text>}
== [<tag0> </tag0> " " <text> " this and that^/" <tag1> "those "
</tag1> "and > these" </text> <tag2> </tag2> <text> "There and^/then"
</text>]
You can get rid of the whitespace-only strings if you want to that are
created due to whitespace between the tags.
Now write the spec:
* any combination of input elements up to <text>
* open <text>
* any combination of "???", <???>, </???> where <text> whould be
inserted if front of each "???"
* </text>
* start the whole process over
Done.
That's all you've told us so far. Each item above is essentially a
parse rule already. Some can be joined together:
* [thru <text>]
* [any [
</text> [thru <text>]
| tag!
| string! mark: (insert back mark <text>) string!
]
]
Now we just assemble:
; skip the immediate string after <text> so we don't add a second one
start-rule: [thru <text> [string! | none]]
parse imput [
start-rule
any [
</text> start-rule ; start over
| tag! ; eat any random tags
| string! mark: (insert back mark <text>) string!
]
]
probe input
And presto!
Sterling
