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Diffstat (limited to 'ChangeLog')
| -rw-r--r-- | ChangeLog | 50 |
1 files changed, 50 insertions, 0 deletions
@@ -1,3 +1,53 @@ +2010-01-05 Kaz Kylheku <kkylheku@gmail.com> + + Implemented the regular expression ~ and & operators. + This turns out to be easy to do in NFA land. + The complement of an NFA has exactly the same number + and configuration of states and transitions, except + that the states have an inverted meaning; and furthermore, + failed character transitions are routed to an extra + state (which in this impelmentation is permanently + allocated and shared by all regexes). The regex & + is implemented trivially using DeMorgan's. + + Also, bugfix: regular expressions like A|B|C are allowed + now by the syntax, rather than constituting syntax error. + Previously, this would have been entered as (A|B)|C. + + * lib.c (comp_s, and_s): New symbol globals. + (obj_init): New symbols interned. + + * lib.h (comp_s, and_s): Declared. + + * parser.l (grammar): Provide new ~ and & tokens in REGEX state. + + * parser.y (regexpr): Constituents of '|' are regexprs, + rather than regbranches (see bugfix note above). + The '&' operator is added. + (regterm): The '~' operator is added. + + * regex.c (struct any_char_set, struct small_char_set, struct + displaced_char_set): refs field added. + (nfa_kind_t): New enum members nfa_super_accept, + nfa_reject, nfa_compl_empty, nfa_compl_wild, + nfa_compl_single, nfa_compl_set. + (nfa_super_accept_state): New static structure. + (nfa_is_accept_state): New inline function. + (char_set_create): Initialize reference count to 1. + (char_set_destroy): Decrement refcount, free if zero. + (char_set_clone): New function. + (nfa_state_empty_convert, nfa_state_merge): Handle nfa_reject state, + the complement of nfa_accept. + (nfa_compl_state, nfa_compl): New functions. + (nfa_compile_regex): Handle new operators. + (nfa_all_states, nfa_closure): Handle new state types. + (nfa_move): Handle new types according to special rules: + the new complemented states that have character transitions have a next + move to the super-accept state if they do not match the input + character. + + * txr.1: Documented new regex operators. + 2009-12-17 Kaz Kylheku <kkylheku@gmail.com> * lib.c (make_package, find_package): Eliminate declaration |