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Parse "as $x |" via precedence climbing #37

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62 changes: 32 additions & 30 deletions jqjq.jq
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Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@ eval "$( \
# Notes:
# - AST is more or less identical to the one used by gojq to make it easier to test parser
# - jq bindings $<name>_ is used if <name> is a keyword as jq (not gojq) does not allow it
# - "string_middle" token is used to distingush between a string that could be an index and
# - "string_middle" token is used to distinguish between a string that could be an index and
# a string that is parts of string interpolation.
#

Expand Down Expand Up @@ -227,9 +227,13 @@ def parse:
# https://www.engr.mun.ca/~theo/Misc/exp_parsing.htm#climbing
# filter is used to disable operators, ex in keyval query
def _op_prec_climb($p; filter):
# debug({_op_prec_climb: .}) |
def _ops:
# debug({ops: .}) |
if filter then null
elif .pipe then {prec: 0, name: "|", assoc: "right"}
# TODO: not as keyword?
elif .ident == "as" then {prec: 0, name: "|", assoc: "right"}
# TODO: understand why jq has left associativity for "," but right seems to give correct parse tree
elif .comma then {prec: 1, name: ",", assoc: "right"}
elif .slash_slash then {prec: 2, name: "//", assoc: "right"}
Expand Down Expand Up @@ -263,6 +267,18 @@ def parse:
| ($next | if . != null then _ops end) as $next_op
| if $next_op and $next_op.prec >= $p then
( .[1:] # consume
#| debug({rest: .})
| ( if $next.ident == "as" then
( _p("pattern") as [$rest, $pattern]
| $rest
| _consume(.pipe) as [$rest, $_]
| [$rest, $pattern]
)
else [., null]
end
) as [$rest, $as_pattern]
#| debug({$as_pattern})
| $rest
| ( if $next_op.assoc == "right" then
_op_prec_climb($next_op.prec; filter)
elif $next_op.assoc == "left" then
Expand All @@ -283,6 +299,7 @@ def parse:
, left: ($t | del(.func_defs))
, right: $t1
}
| if $as_pattern then .pattern = $as_pattern end
| if $func_defs then
.func_defs = $func_defs
else .
Expand Down Expand Up @@ -877,21 +894,6 @@ def parse:
, {optional: true}
]
)
//
( _keyword("as")
| _p("pattern") as [$rest, $pattern]
| $rest
| _consume(.pipe)[0]
| _p("query") as [$rest, $body]
| $rest
| [ .
, { bind:
{ body: $body
, patterns: [$pattern]
}
}
]
)
);

# .
Expand Down Expand Up @@ -1327,6 +1329,7 @@ def eval_ast($query; $path; $env; undefined_func):
, suffix_list: [{$optional}]
}
, $op
, $pattern
, $func_defs
}
| ( ( ($func_defs // [])
Expand Down Expand Up @@ -1939,17 +1942,7 @@ def eval_ast($query; $path; $env; undefined_func):
def _e_suffix($suffix; $path; $input; $opt):
( . as [$p, $v]
| $input
| if $suffix.bind then
# as $name | <body>
( $suffix.bind as {$body, patterns: [$pattern]}
| ($pattern | _e_pattern($v)) as $pattern_env
| _e(
$suffix.bind.body;
$path;
$query_env + $pattern_env
)
)
elif $suffix.index then
| if $suffix.index then
# .<index>
try
( $v
Expand Down Expand Up @@ -2028,9 +2021,18 @@ def eval_ast($query; $path; $env; undefined_func):
def _r: _e($right; $path; $query_env);
if $op == "," then _l, _r
elif $op == "|" then
( _e($left; $path; $query_env) as [$p, $v]
| $v
| _e($right; $p; $query_env)
( . as $input
| _e($left; $path; $query_env) as [$p, $v]
| if $pattern then
( ($pattern | _e_pattern($v)) as $pattern_env
| _e(
$right;
$path;
$query_env + $pattern_env
)
)
else $v | _e($right; $p; $query_env)
end
)
elif $op == "or" then _l[1] or _r[1] | [[null], .]
elif $op == "and" then _l[1] and _r[1] | [[null], .]
Expand Down
27 changes: 26 additions & 1 deletion jqjq.test
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Original file line number Diff line number Diff line change
Expand Up @@ -1173,10 +1173,35 @@ ascii_downcase
"123@ABCDEFGHIJKLMNOPQSTUVXYZ["
"123@abcdefghijklmnopqstuvxyz["

# precedence of expr as $v | ...
# https://github.com/jqlang/jq/pull/3326
1 + 2 as $x | -$x
null
-3

1 + 2 as $x | 3 | [$x]
null
[3]

# SKIP_JQ
# test below does not work with standard jq because of missing features or
# they test jqjq specific things

1, 2 as $x | 3 | [$x]
null
[1]
[2]

1, 2 | 3 | [.]
null
[3]
[3]

1, 2 as $x | 3 | [.]
null
[3]
[3]

# TODO: proper message
# test binding with path
def t(v; f): try path(v | f) catch "invalid"; [(null, true, false, 1, "abc", [], {}) as $v | t($v; .)]
Expand Down Expand Up @@ -1270,6 +1295,6 @@ null
3

# and env don't leak into eval (maybe should be an option?)
try 3 as $e | eval("$e") catch .
try (3 as $e | eval("$e")) catch .
null
"undefined function $e"