diff options
| -rw-r--r-- | ChangeLog | 12 | ||||
| -rw-r--r-- | parser.y | 12 |
2 files changed, 19 insertions, 5 deletions
@@ -1,5 +1,17 @@ 2014-10-18 Kaz Kylheku <kaz@kylheku.com> + * parser.y: Allow TXR to support large programs, and efficiently so. + (clauses_rev): New grammar symbol. Uses a left-recursive rule that + does not consume an amount of parser stack proportional to the number + of clauses, and sticks to efficient consing, which means that + the list is built up in reverse. + (clauses): Now just a wrapper rule for clauses_rev which nreverses + its output. + (clauses_opt): Retargetted to use clauses_rev instead of clauses, + and reverse its output. + +2014-10-18 Kaz Kylheku <kaz@kylheku.com> + Deal with situation when GC is disabled and the freshobj array runs out of room. This could happen when parsing a really large TXR program, since gc is disabled during parsing. Currently it asserts, which @@ -97,7 +97,7 @@ int yylex(union YYSTYPE *, yyscan_t scanner); %token <chr> REGCHAR REGTOKEN LITCHAR SPLICE -%type <val> spec clauses clauses_opt clause +%type <val> spec clauses_rev clauses clauses_opt clause %type <val> all_clause some_clause none_clause maybe_clause block_clause %type <val> cases_clause choose_clause gather_clause collect_clause until_last %type <val> collect_repeat @@ -144,11 +144,13 @@ spec : clauses { parser->syntax_tree = $1; } ; -clauses : clause { $$ = cons($1, nil); } - | clause clauses { $$ = cons($1, $2); } - ; +clauses : clauses_rev { $$ = nreverse($1); } + +clauses_rev : clause { $$ = cons($1, nil); } + | clauses_rev clause { $$ = cons($2, $1); } + ; -clauses_opt : clauses { $$ = $1; } +clauses_opt : clauses_rev { $$ = nreverse($1); } | /* empty */ { $$ = nil; } ; |