Re: Invalid YAML output from EXPLAIN

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Dean Rasheed wrote:
...
> So the current code in escape_yaml() is inadequate for producing valid
> YAML. I think it would have to also consider at least the following
> characters as special "-" ":" "[" "]" "{" "}" "," "\"" "'"
> "|" "*" "&". Technically, it would also need to trap empty strings,
> and strings with leading or trailing whitespace.
>
> Making escape_yaml() completely bulletproof with this approach would
> be quite difficult, and (IMO) not worth the effort
...

Doesn't seem like a lot of effort to me. You've already laid out most of
the exceptions above, although they require a few tweaks.
The rules should be:

Requires quoting only if the first character:
& * ! | > ' " % @ ` #

Same as above, but no quoting if the second character is "safe":
- ? :

Always requires quoting:
":<space>" "<space>#" aka ': ' ' #'

Always requires quoting:
, [ ] { }

Always require quoting:
(leading space) (trailing space) (empty string)

See:
http://yaml.org/spec/1.2/spec.html section 5.3 and 7.3.3

- --
Greg Sabino Mullane greg(at)turnstep(dot)com
End Point Corporation http://www.endpoint.com/
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