New #J syntax for JSON objects in TXR Lisp.

(needs buffer literal error message cleanup)

* parser.c (json_s): New symbol variable.
(is_balanced_line): Follow braces out of initial state.
This concession allows the listener to accept input
like #J{"a":"b"}.
(me_json): New static function (macro expander). The #J X
syntax produces a (json Y) form, with the JSON syntax X
translated to a Lisp object Y. If that is evaluated,
this macro translates it to (quote Y).
(parse_init): initialize json_s variable with interned symbol,
and register the json macro.

* parser.h (json_s): Declared.
(end_of_json): Declared.

* parser.l (num_esc): Treat u escape sequences in the same way
as x. This function can then be used for handling the \u
escapes in JSON string literals.
(DIG19, JNUM, JPUNC, NJPUNC): New lex named patterns.
(JSON, JLIT): New lex start conditions.
(grammar): Recognize #J syntax, mapping to HASH_J token,
which transitions into JSON start state.
In JSON start state, handle all the elements: numbers,
keywords, arrays and objects. Transition into JLIT state.
In JLIT start state, handle all the elements of JSON string
literals, including surrogate pair escapes.
JSON literals share the fallback {UANY} fallback patter with
other literals.
(end_of_jason): New function.

* parser.y (HASH_J, JSKW): New token symbols.
(json, json_val, json_vals, json_pairs): New nonterminal
symbols, and rules.
(i_expr, n_expr): Generate json nonterminal, to hook the
stuff into the grammar.
(yybadtoken): Handle JKSW and HASH_J tokens.

* lex.yy.c.shipped, y.tab.c.shipped, y.tab.h.shipped:
Updated.

1 files changed, 2 insertions, 0 deletions

diff --git a/parser.h b/parser.h
index d27ba0f9..851e62ff 100644
--- a/parser.h
+++ b/parser.h
@@ -75,6 +75,7 @@ extern const wchar_t *spec_file;
 extern val form_to_ln_hash;
 extern val parser_s, unique_s, circref_s;
 extern val rec_source_loc_s;
+extern val json_s;
 void yydebug_onoff(int);
 void yyerror(scanner_t *scanner, parser_t *, const char *s);
 void yyerr(scanner_t *scanner, const char *s);
@@ -83,6 +84,7 @@ void yybadtoken(parser_t *, int tok, val context);
 void end_of_regex(scanner_t *scanner);
 void end_of_char(scanner_t *scanner);
 void end_of_buflit(scanner_t *scanner);
+void end_of_json(scanner_t *scanner);
 #ifdef SPACE
 int yylex(YYSTYPE *yylval_param, yyscan_t yyscanner);
 #endif