Subject: Re: Revisiting split-sequence and patterns
From: Erik Naggum <erik@naggum.net>
Date: Sat, 01 Dec 2001 13:30:57 GMT
Newsgroups: comp.lang.lisp
Message-ID: <3216202256157250@naggum.net>

* Jeff Greif
| I'm not sure your reason is strong enough to allow such a line to fall
| outside the usage of this new split-sequence functionality.

  I am.  You need a real parser, not just a "split" function to get this
  kind of functionality.  OK, I called my function "parse-delimited-list"
  and that was probably misleading, but if we do this, it will grow into a
  full-fledged programmable parser like the Common Lisp reader, and then it
  is a better project to make the reader more powerful.  (I am working on
  that, too, in particular to get a handle on the function that decides
  when something is a symbol.)

| It might be useful to add one more syntax pattern -- characters that are
| punctuation (delimit tokens) but also *are* tokens (unless escaped or
| appearing inside the multiple escaped sequence).  Using that pattern,
| the line above could be tokenized as ( "[" "Wed" "Oct" "11" ... "]" ...)
| and a higher level of parsing could handle the rectangular brackets.

  I think this is a much better design.  There is but one drawback, which
  may be a feature, and that is that you no longer have any special rules
  inside the delimiter pairs, which I would kind of expect for a language
  that uses matching delimiters.

///
-- 
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