diff options
Diffstat (limited to 'src/regex.ur')
| -rw-r--r-- | src/regex.ur | 58 |
1 files changed, 42 insertions, 16 deletions
diff --git a/src/regex.ur b/src/regex.ur index 0024561..b379646 100644 --- a/src/regex.ur +++ b/src/regex.ur @@ -20,33 +20,41 @@ fun concat (strings : list string) : string = (* Substrings and matches *) -type substring = {Start : int, Len : int} -type match = {Whole : substring, Groups : list substring} +type counted_substring = {Start : int, Len : int} +type match a = {Whole : a, Groups : list a} -fun substring_offset (delta : int) (substring : substring) : substring = +fun substring_offset (delta : int) (substring : counted_substring) + : counted_substring = {Start = substring.Start + delta, Len = substring.Len} -fun match_offset (delta : int) (match : match) : match = - {Whole = substring_offset delta match.Whole, - Groups = List.mp (substring_offset delta) match.Groups} +fun mp [a ::: Type] [b ::: Type] (f : a -> b) (match : match a) : match b = + {Whole = f match.Whole, Groups = List.mp f match.Groups} + +fun match_offset (delta : int) + : match counted_substring -> match counted_substring = + mp (substring_offset delta) (* Returns the index of the character just _after_ a match. *) -fun after_match (match : match) : int = +fun after_match (match : match counted_substring) : int = match.Whole.Start + match.Whole.Len +fun get_substrings (haystack : string) + : match counted_substring -> match string = + mp (String.substring haystack) + (* Unmarshaling FFI types *) structure FFI = Regex__FFI (* Unmarshals an 'FFI.substring_t' from C into Ur. *) -fun unmarshal_substring (substring : FFI.substring_t) : substring = +fun unmarshal_substring (substring : FFI.substring_t) : counted_substring = {Start = FFI.substring_start substring, Len = FFI.substring_length substring} (* Unmarshals an 'FFI.substring_list_t' from C into Ur. *) fun unmarshal_substring_list (substrings : FFI.substring_list_t) - : option match = + : option (match counted_substring) = case FFI.substring_list_length substrings of 0 => None | n_groups => @@ -70,11 +78,14 @@ fun validate (regex : string) : string = then regex else error <xml>regex: Empty regex</xml> -fun match needle haystack = +fun match' needle haystack = unmarshal_substring_list (FFI.do_match (validate needle) haystack) -fun all_matches needle haystack = - case match needle haystack of +fun match needle haystack = + Option.mp (get_substrings haystack) (match' needle haystack) + +fun all_matches' needle haystack = + case match' needle haystack of None => [] | Some match => let @@ -82,14 +93,17 @@ fun all_matches needle haystack = in match :: List.mp (match_offset remaining_start) - (all_matches needle + (all_matches' needle (String.suffix haystack remaining_start)) end -fun transform needle f_nomatch f_match haystack = +fun all_matches needle haystack = + List.mp (get_substrings haystack) (all_matches' needle haystack) + +fun transform' needle f_nomatch f_match haystack = let val haystack_length = String.length haystack - val matches = all_matches needle haystack + val matches = all_matches' needle haystack in (* Handle the first nonmatching region. *) f_nomatch {Start = 0, @@ -122,8 +136,20 @@ fun transform needle f_nomatch f_match haystack = matches) end +fun transform needle f_nomatch f_match haystack = + transform' needle + (fn s => f_nomatch (String.substring haystack s)) + (fn m => f_match (get_substrings haystack m)) + haystack + +fun transform_matches' needle f_match haystack = + transform' needle (String.substring haystack) f_match haystack + fun transform_matches needle f_match haystack = - transform needle (String.substring haystack) f_match haystack + transform' needle + (String.substring haystack) + (fn m => f_match (get_substrings haystack m)) + haystack fun replace needle haystack replacement = transform_matches needle (fn _ => replacement) haystack |