From 887e2d63c75de383a4454bb9ea1fa8be6e7d102b Mon Sep 17 00:00:00 2001
From: joachimschmidt557 <joachim.schmidt557@outlook.com>
Date: Wed, 20 Feb 2019 18:49:45 +0100
Subject: [PATCH] Maybe finished NFAs

---
 DFA.fs              |  2 +-
 IsNumericChecker.fs | 19 +++++++++++++++++++
 NFA.fs              | 26 +++++++++++++++++++++++++-
 3 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/DFA.fs b/DFA.fs
index af38170..cabfe0a 100644
--- a/DFA.fs
+++ b/DFA.fs
@@ -49,7 +49,7 @@ let processChar (dfa: DFA) (state: State) (char: Char) =
 let rec processCharArray (dfa: DFA) (state: State) (charArr: Char list) =
     match charArr with
     | [] -> state
-    | _ -> processCharArray dfa (processChar dfa state charArr.Head) charArr.Tail
+    | head :: tail -> processCharArray dfa (processChar dfa state head) tail
 
 let acceptsWord (dfa: DFA) (word: String) =
     dfa.acceptingStates
diff --git a/IsNumericChecker.fs b/IsNumericChecker.fs
index c998d0f..5247b45 100644
--- a/IsNumericChecker.fs
+++ b/IsNumericChecker.fs
@@ -2,6 +2,7 @@ module Tests
 
 open System
 open DFA
+open NFA
 
 let numericDFA:DFA = {
     sigma = Seq.toList "01ab";
@@ -19,9 +20,27 @@ let numericDFA:DFA = {
     acceptingStates = [{name = "yes"}]
 }
 
+let numericNFA:NFA = {
+    sigma = Seq.toList "01ab";
+    states = [
+        {name = "yes"}
+    ];
+    delta = (fun x y ->
+        match (x, y) with
+        | ({name = "yes"}, '0') -> [{name = "yes"}]
+        | ({name = "yes"}, '1') -> [{name = "yes"}]
+        | _ -> []
+    );
+    beginState = {name = "yes"};
+    acceptingStates = [{name = "yes"}]
+}
+
 let test = 
     printfn "Testing numeric checker DFA"
     printfn "Is valid DFA: %b" (DFA.validateDFA numericDFA)
     printfn "0101: %b" (DFA.acceptsWord numericDFA "0101")
     printfn "01a1: %b" (DFA.acceptsWord numericDFA "01a1")
+    printfn "Testing numeric checker NFA"
+    printfn "0101: %A" (NFA.acceptsWord numericNFA "0101")
+    printfn "01a1: %b" (NFA.acceptsWord numericNFA "01a1")
     0
\ No newline at end of file
diff --git a/NFA.fs b/NFA.fs
index 03ecc6f..db62d96 100644
--- a/NFA.fs
+++ b/NFA.fs
@@ -14,4 +14,28 @@ type NFA = {
 }
 
 let processChar (nfa: NFA) (state: State) (char: Char) =
-    nfa.delta state char
\ No newline at end of file
+    nfa.delta state char
+
+let rec processCharArray (nfa: NFA) (states: State list) (charArr: Char list) : State list =
+    match charArr with
+    | [] -> states
+    | head :: tail -> 
+        processCharArray
+            nfa
+            (
+                states
+                |> List.map (fun x -> processChar nfa x head)
+                |> List.filter (List.isEmpty >> not)
+                |> (fun x -> 
+                    if not (List.isEmpty x) then
+                        List.reduce List.append x 
+                    else [])
+            )
+            tail
+
+let acceptsWord nfa word = 
+    match processCharArray nfa [nfa.beginState] (Seq.toList word) with
+    | [] -> false
+    | x -> x
+        |> List.map (fun x -> List.contains x nfa.acceptingStates)
+        |> List.exists id