From fec3331894a8a433d1a58ec2c929743bbf449cb1 Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Sun, 11 Oct 2020 09:34:59 +0200 Subject: [PATCH] keyval: Fix and clarify grammar The grammar has a few issues: * key-fragment = / [^=,.]* / Prose restricts key fragments: they "must be valid QAPI names or consist only of decimal digits". Technically, '' consists only of decimal digits. The code rejects that. Fix the grammar. * val = { / [^,]* / | ',,' } Use + instead of *. Accepts the same language. * val-no-key = / [^=,]* / The code rejects an empty value. Fix the grammar. * Section "Additional syntax for use with an implied key" is confusing. Rewrite it. Signed-off-by: Markus Armbruster Message-Id: <20201011073505.1185335-2-armbru@redhat.com> Reviewed-by: Eric Blake Signed-off-by: Kevin Wolf --- util/keyval.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/util/keyval.c b/util/keyval.c index 13def4af54..82d8497c71 100644 --- a/util/keyval.c +++ b/util/keyval.c @@ -16,8 +16,8 @@ * key-vals = [ key-val { ',' key-val } [ ',' ] ] * key-val = key '=' val * key = key-fragment { '.' key-fragment } - * key-fragment = / [^=,.]* / - * val = { / [^,]* / | ',,' } + * key-fragment = / [^=,.]+ / + * val = { / [^,]+ / | ',,' } * * Semantics defined by reduction to JSON: * @@ -71,12 +71,16 @@ * Awkward. Note that we carefully restrict alternate types to avoid * similar ambiguity. * - * Additional syntax for use with an implied key: + * Alternative syntax for use with an implied key: * - * key-vals-ik = val-no-key [ ',' key-vals ] - * val-no-key = / [^=,]* / + * key-vals = [ key-val-1st { ',' key-val } [ ',' ] ] + * key-val-1st = val-no-key | key-val + * val-no-key = / [^=,]+ / * - * where no-key is syntactic sugar for implied-key=val-no-key. + * where val-no-key is syntactic sugar for implied-key=val-no-key. + * + * Note that you can't use the sugared form when the value contains + * '=' or ','. */ #include "qemu/osdep.h"