From d0923800e0b2b2476ff39d8144549172b5c668cb Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Thu, 29 Jul 2021 08:05:46 -0700
Subject: parser: allow trailing commas in json, via opt-in flag.
* parser.c (read_bad_json_s): New symbol variable.
(parser_common_init): Propagate value of *read-bad-json* into
read_bad_json flag in parser structure.
(parser_init): Initialize read_bad_json_s and register the
*read-bad-json* dynamic variable.
* parser.h (struct parser): New member, read_bad_json.
(read_bad_json_s): Declared.
* parser.y (json_val): Support an opt_comma symbol just before
the closing bracket or brace.
(opt_comma): New nonterminal symbol. Recognizes ',' or nothing.
Error is flagged if ',' is recognized, and *read-bad-json*
is nil.
* y.tab.c.shipped: Updated.
* tests/010/json.tl: New tests.
* txr.1: Documented.
---
parser.y | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
(limited to 'parser.y')
diff --git a/parser.y b/parser.y
index 9e15ca44..7e068714 100644
--- a/parser.y
+++ b/parser.y
@@ -970,13 +970,15 @@ json_val : NUMBER { $$ = $1; }
| '"' litchars '"' { $$ = $2;
rl($$, num(parser->lineno)); }
| '[' ']' { $$ = vector(zero, nil); }
- | '[' json_vals ']' { $$ = if3(vectorp($2),
+ | '[' json_vals
+ opt_comma ']' { $$ = if3(vectorp($2),
$2,
rl(cons(vector_lit_s,
cons(nreverse($2), nil)),
$2)); }
| '{' '}' { $$ = make_hash(hash_weak_none, t); }
- | '{' json_pairs '}' { $$ = if3(hashp($2),
+ | '{' json_pairs
+ opt_comma '}' { $$ = if3(hashp($2),
$2,
rl(cons(hash_lit_s,
cons(nil, nreverse($2))),
@@ -1003,6 +1005,11 @@ json_val : NUMBER { $$ = $1; }
yybadtok(yychar, lit("JSON hash")); }
;
+opt_comma : ',' { if (!parser->read_bad_json)
+ yyerr("trailing comma in JSON array"); }
+ |
+ ;
+
json_vals : json_val { $$ = if3(parser->quasi_level > 0 &&
unquotes_occur($1, 0),
cons($1, nil),
--
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