The emitter kept its own list of reserved words and number shapes,
apart from the parser's, and the two disagreed: the string yes was
written plain and read back as a boolean, as were 0x1F, 1_000 and
.inf. The parser's reading of a plain scalar is now one type that
both use, and the emitter quotes what does not read back as a string.
Also quoted: the merge key, the document end marker, and a string
with a CR+LF break, which was written raw.
Mihaela Mihaljevic
ae85ec97c9