Allow question marks inside of plain scalars in flow collections #128
Description
See also yaml/libyaml#105
http://yaml.org/spec/1.1/#id907281
Question marks aren't mentioned as special inside of plain scalars here.
To be an indicator for an explicit key, it must be at the beginning and followed by a space or newline.
The following cases should be allowed:
[foo?bar]
[foo ? bar]
This would allow [ http://example/query?a=b ].
Even this one should be allowed, but it would potentially break existing code:
[?foo]
# same as
["?foo"]
# but currently parsed as
[? foo ]
The Spec:
The first plain character is further restricted to avoid most indicators as these
would cause ambiguity with various YAML structures. However, the first character
may be “-”, “?” or “:” provided it is followed by a non-space character.
[157] ns-plain-first-char(c) ::= ( ns-plain-char(c) - c-indicator )
| ( ( “-” | “?” | “:” ) ns-plain-char(c) )