4 ms·

Well, it is and isn't novel. S-expressions have been around since McCarthy, XML since the mid-90's. The point of the article is that XML is a more verbose re-in

by txru 7y ago

Well, it is and isn't novel. S-expressions have been around since McCarthy, XML since the mid-90's. The point of the article is that XML is a more verbose re-interpretation of s-expressions-- it's hard to find things that XML brings to the table that sexps don't have. What's more, inside editors, there are really clever things that manipulate sexprs, move them around, redefine their semantic meaning. XML usually doesn't work quite that way, not as a first intent.

tannhaeuser 7y ago
SGML has been around since the 1960s, and XML is specified as a proper subset of it. SGML/XML isn't so much about (trivial) nesting than it is about content models, eg. the language defined by a regular expression admitted/recognized as the content of a particular element. Markup is also first and foremost a plain text format, optionally tagged by start-/end-element tags, unlike sexprs which need quotes around individual spans of text. Try telling an author to use verbose quoting (and escaping for quotes) for what makes the majority of his text format, or try edititing a large text with verbose sexpr yourself, and you'll see why nobody uses sexprs for semistructured text.
- txru 7y ago
  I take your point, and I really don't want to be the spark of a syntactic flamewar. I suspected I was missing something, and that the $angle_bracketed_format was older, but I was searching the wrong things. It seems to me, though, that escaping is just something that's going to be tricky everywhere, and a decent first line solution, wherever you are, is to have a really rare set of characters represent your begin/end string marks. In Python, """text""", Postgres has $$text$$, non-ASCII characters in other formats. XML and sexps are both susceptible to that issue-- both of their escapes are, themselves, escapable. To either one, if you have a subregion that's likely to be unintentionally escaped, then you create a boundary where you either explicitly escape every one, or you refuse to acknowledge previously accepted delimiters. As an example, lisps have (quote term) rather than 'term when you're writing macros and concerned with macro-expansion. To your regex point, there are lisps that definitely did awful deeds with that, particularly emacs lisp, but the more recent ones have solutions just like other modern programming languages and markups do. To me the unending escape just kind of seems like a universal bug. While lisp is just as susceptible, lisps have perfectly reasonable ways of treating these problems-- separate, make distinct, and as last resort, escape.
goto11 7y ago
SGML came out of document authoring and publishing. SGML is more suited for this domain because (among other things) you don't have to quote every single string. It is not like the SGML community didn't know about s-expressions - DSSSL the style language for SGML was based on scheme, so they recognized s-expressions were appropriate for some domains.

by txru 7y ago

tannhaeuser 7y ago

SGML has been around since the 1960s, and XML is specified as a proper subset of it. SGML/XML isn't so much about (trivial) nesting than it is about content models, eg. the language defined by a regular expression admitted/recognized as the content of a particular element. Markup is also first and foremost a plain text format, optionally tagged by start-/end-element tags, unlike sexprs which need quotes around individual spans of text. Try telling an author to use verbose quoting (and escaping for quotes) for what makes the majority of his text format, or try edititing a large text with verbose sexpr yourself, and you'll see why nobody uses sexprs for semistructured text.

txru 7y ago
I take your point, and I really don't want to be the spark of a syntactic flamewar. I suspected I was missing something, and that the $angle_bracketed_format was older, but I was searching the wrong things. It seems to me, though, that escaping is just something that's going to be tricky everywhere, and a decent first line solution, wherever you are, is to have a really rare set of characters represent your begin/end string marks. In Python, """text""", Postgres has $$text$$, non-ASCII characters in other formats. XML and sexps are both susceptible to that issue-- both of their escapes are, themselves, escapable. To either one, if you have a subregion that's likely to be unintentionally escaped, then you create a boundary where you either explicitly escape every one, or you refuse to acknowledge previously accepted delimiters. As an example, lisps have (quote term) rather than 'term when you're writing macros and concerned with macro-expansion. To your regex point, there are lisps that definitely did awful deeds with that, particularly emacs lisp, but the more recent ones have solutions just like other modern programming languages and markups do. To me the unending escape just kind of seems like a universal bug. While lisp is just as susceptible, lisps have perfectly reasonable ways of treating these problems-- separate, make distinct, and as last resort, escape.

goto11 7y ago

SGML came out of document authoring and publishing. SGML is more suited for this domain because (among other things) you don't have to quote every single string. It is not like the SGML community didn't know about s-expressions - DSSSL the style language for SGML was based on scheme, so they recognized s-expressions were appropriate for some domains.