When the lexer isn't in its start state at the end of input, it's
working on a token. To flush it out, it needs to transit to its start
state on "end of input" lookahead.
There are two ways to the start state, depending on the current state:
* If the lexer is in a TERMINAL(JSON_FOO) state, it can emit a
JSON_FOO token.
* Else, it can go to IN_ERROR state, and emit a JSON_ERROR token.
There are complications, however:
* The transition to IN_ERROR state consumes the input character and
adds it to the JSON_ERROR token. The latter is inappropriate for
the "end of input" character, so we suppress that. See also recent
commit a2ec6be72b "json: Fix lexer to include the bad character in
JSON_ERROR token".
* The transition to a TERMINAL(JSON_FOO) state doesn't consume the
input character. In that case, the lexer normally loops until it is
consumed. We have to suppress that for the "end of input" input
character. If we didn't, the lexer would consume it by entering
IN_ERROR state, emitting a bogus JSON_ERROR token. We fixed that in
commit bd3924a33a.
However, simply breaking the loop this way assumes that the lexer
needs exactly one state transition to reach its start state. That
assumption is correct now, but it's unclean, and I'll soon break it.
Clean up: instead of breaking the loop after one iteration, break it
after it reached the start state.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20180831075841.13363-3-armbru@redhat.com>
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