humza/sml-projects
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

refactor nfa.sml so that lists in CONCAT and ALTERNATION cases don't need the state to be tupled with the regex

Browse Source
This commit is contained in:
Humza Shahid
2025-09-30 13:52:35 +01:00
parent 45fbd85183
commit 5fa784b4c6
1 changed files with 43 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files

77
fcore/search-list/nfa.sml
View File

@@ -4,13 +4,23 @@ struct
datatype regex =
CHAR_LITERAL of char * state
| CONCAT of (regex * state) list * state
| ALTERNATION of (regex * state) list * state
| CONCAT of regex list * state
| ALTERNATION of regex list * state
| ZERO_OR_ONE of regex * state
| ZERO_OR_MORE of regex * state
| ONE_OR_MORE of regex * state
| GROUP of regex * state
fun getState regex =
case regex of
CHAR_LITERAL (_, state) => state
| CONCAT (_, state) => state
| ALTERNATION (_, state) => state
| ZERO_OR_ONE (_, state) => state
| ZERO_OR_MORE (_, state) => state
| ONE_OR_MORE (_, state) => state
| GROUP (_, state) => state
structure NfaMatch =
struct
(* test to see if NFA matches.
@@ -38,42 +48,46 @@ struct
local
fun loop (tl, maxValid) =
case tl of
(_, VALID curValid) :: tl => loop (tl, Int.max (maxValid, curValid))
| (_, UNTESTED) :: _ => UNTESTED
| (_, INVALID) :: _ =>
raise Fail
"nfa.sml 24: \
\should not have INVALID state in acc"
hd :: tl =>
(case getState hd of
VALID curValid => loop (tl, Int.max (curValid, maxValid))
| UNTESTED => UNTESTED
| INVALID =>
raise Fail
"nfa.sml 24: \
\should not have INVALID state in acc")
| [] => VALID maxValid
in
fun getAlternationState acc =
case acc of
(_, VALID maxValid) :: tl => loop (tl, maxValid)
| (_, UNTESTED) :: _ => UNTESTED
| (_, INVALID) :: _ =>
raise Fail
"nfa.sml 26: \
\should not have INVALID state in acc"
hd :: tl =>
(case getState hd of
VALID maxValid => loop (tl, maxValid)
| UNTESTED => UNTESTED
| INVALID =>
raise Fail
"nfa.sml 65: \
\should not have INVALID state in acc")
| [] => UNTESTED
end
fun rebuildConcat (lst, chr, idx) =
case lst of
[(hd, _)] =>
[hd] =>
let
val (hd: regex, state: state) = rebuild (hd, chr, idx)
val result = [(hd, state)]
val result = [hd]
val concat = CONCAT (result, state)
in
(concat, state)
end
| (hd, _) :: tl =>
| hd :: tl =>
let
val (hd, state) = rebuild (hd, chr, idx)
in
case state of
UNTESTED =>
let val concat = CONCAT ((hd, state) :: tl, UNTESTED)
let val concat = CONCAT (hd :: tl, UNTESTED)
in (concat, UNTESTED)
end
| INVALID =>
@@ -93,25 +107,25 @@ struct
and rebuildAlternation (lst, chr, idx, acc) =
case lst of
[(hd, _)] =>
[hd] =>
let
val (hd, state) = rebuild (hd, chr, idx)
val acc =
case state of
VALID _ => (hd, state) :: acc
| UNTESTED => (hd, state) :: acc
VALID _ => hd :: acc
| UNTESTED => hd :: acc
| INVALID => acc
val state = getAlternationState acc
in
(ALTERNATION (acc, state), state)
end
| (hd, _) :: tl =>
| hd :: tl =>
let
val (hd, state) = rebuild (hd, chr, idx)
val acc =
case state of
VALID _ => (hd, state) :: acc
| UNTESTED => (hd, state) :: acc
VALID _ => hd :: acc
| UNTESTED => hd :: acc
| INVALID => acc
in
rebuildAlternation (tl, chr, idx, acc)
@@ -252,8 +266,7 @@ struct
SOME rhs =>
let
val rhs = GROUP (rhs, UNTESTED)
val result = CONCAT
([(lhs, UNTESTED), (rhs, UNTESTED)], UNTESTED)
val result = CONCAT ([lhs, rhs], UNTESTED)
in
climb (groupEndIdx + 1, str, result, groupLevel)
end
@@ -274,10 +287,8 @@ struct
val result =
case rhs of
ALTERNATION (lst, state) =>
ALTERNATION ((lhs, UNTESTED) :: lst, UNTESTED)
| _ =>
ALTERNATION
([(lhs, UNTESTED), (rhs, UNTESTED)], UNTESTED)
ALTERNATION (lhs :: lst, UNTESTED)
| _ => ALTERNATION ([lhs, rhs], UNTESTED)
in
SOME (pos, result)
end
@@ -317,10 +328,8 @@ struct
let
val result =
case rhs of
CONCAT (lst, _) =>
CONCAT ((lhs, UNTESTED) :: lst, UNTESTED)
| _ =>
CONCAT ([(lhs, UNTESTED), (rhs, UNTESTED)], UNTESTED)
CONCAT (lst, _) => CONCAT (lhs :: lst, UNTESTED)
| _ => CONCAT ([lhs, rhs], UNTESTED)
in
SOME (pos, result)
end