Previously, bindings were parsed as the combination of two tokens:
'$' IDENT
This meant that using a keyword as variable name (e.g. $then, $label)
did not work.
Attempts were made to allow $keyword to work by adding some '$' Keyword
rules in the parser, but this did not allow $keyword in all places:
jq --arg label foo -n '$label' # ok
jq -n '"foo" as $label | .' # error
Treating $foo as a single token is much simpler, in my opinion.
This patch also changes how LOC is lexed: "$__loc__" instead of as
"__loc__" that gets combined with '$' in the parser.
This patch also disallows having spaces after '$' when recalling a
variable `$ foo' since that was probably just an unintentional side
effect of the implementation, and it was not documented.
Fixes#2675
The primary purpose of this commit is to rectify most problems with
`gsub` (and also `sub` with the `g` option), in particular fix#1425 ('\b'),
fix#2354 (lookahead), and fix#2532 (regex == `"^(?!cd ).*$|^cd "`).
This commit also partly resolves#2148 and resolves#1206 in that
`gsub` no longer loops infinitely; however, because the new `gsub`
depends critically on `match/2`, the behavior when regex == `""` is
sometimes non-standard.
The documentation has been updated to reflect the fact that `sub`
and `gsub` are intended to be regular in the second argument.
Also, `_nwise/1` has been tweaked to take advantage of TCO.
When the string transformation to number failed, all following
transformation failed too.
This happend because status in decNumberFromString function is
updated just in error case. Reusing the DEC_CONTEXT that failed
before results into error even if the string is valid number.
We need to be careful to not grab an extra reference when mutating data
structures because that means we make extra copies. Doing that every
time in `_modify` is really painful, as that function implements `|=`
and all modify-assign operators.
`jv_setpath()` also grabs additional references, so this is not the only
fix needed for the modify-assign operators to not be accidentally
quadratic.
We have to use `LOADVN` in order to make this fix possible, so we should
really byte-code `_modify` rather than jq-code it. However, as a
stop-gap to make this fix easier, I'm adding syntax for referring to a
`$binding` such that you get `LOADVN` instead of `LOADV`.
This syntax is not meant to be used outside jq's internals! Therefore
it is not documented. I promise to break it later, so don't use it!
TBD, but later:
- Optimize `_modify` for the case where `update` outputs more than one
value.
This is trivial: add a `setpath($p; null)` in the middle of `_modify`
before calling `update`. But unfortunately the VM retains a
reference to `value_at_path` for path expression checking, and fixing
that will require more work.
We need to be careful to not grab an extra reference when mutating
data structures because that means we make extra copies. Doing that
every time in `jv_setpath()` is really painful, as that function is used
in `_modify/2`, which is used in `|=` and all modify-assign operators.
`_modify` also grabs additional references, so this is not the only fix
needed for the modify-assign operators to not be accidentally quadratic.
liquidaty