parser: new *read-unknown-structs* variable.

* parser.c (read_unknown_structs_s): New symbol variable.
(parser_common_init): Initialize read_unknown_structs flag
member of the parser structure from the new special variable.
(parse_init): Initialize read_unknown_struct_s variable.
Register the *read-unknown-structs* dynamic variable.

* parser.h (struct parser): New member, read_unknown_structs.
(read_unknown_structs_s): Declared.

* parser.y (struct): Generate the struct literal syntax not
only for quasiquoted structures, but for structures with an
unknown type name, if the read_unkonwn_structs flag is set.

* txr.1: Documented.

* share/txr/stdlib/doc-syms.tl: Regenerated.

* y.tab.c.shipped: Regenerated.

1 files changed, 2 insertions, 1 deletions

diff --git a/parser.h b/parser.h
index a8a64b97..53bfa5ad 100644
--- a/parser.h
+++ b/parser.h
@@ -65,6 +65,7 @@ struct parser {
   struct yy_token tok_pushback[4];
   int tok_idx;
   int rec_source_loc;
+  int read_unknown_structs;
 };
 #endif
 
@@ -74,7 +75,7 @@ extern const int have_yydebug;
 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 rec_source_loc_s, read_unknown_structs_s;
 extern val json_s;
 void yydebug_onoff(int);
 void yyerror(scanner_t *scanner, parser_t *, const char *s);