From 7b3db216b9c9f8e34b69cd80e1236fc0e8992bbb Mon Sep 17 00:00:00 2001
From: Meisterlala <6453306+Meisterlala@users.noreply.github.com>
Date: Thu, 23 Jul 2020 19:25:21 +0200
Subject: [PATCH] Homework 3

---
 Programming Languages/Part A/Unit 3/hw3.sml | 86 +++++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/Programming Languages/Part A/Unit 3/hw3.sml b/Programming Languages/Part A/Unit 3/hw3.sml
index 8240e7e..999e77f 100644
--- a/Programming Languages/Part A/Unit 3/hw3.sml	
+++ b/Programming Languages/Part A/Unit 3/hw3.sml	
@@ -39,3 +39,89 @@ datatype typ = Anything
 
 fun only_capitals sl = 
 	List.filter (fn fs => Char.isUpper(String.sub(fs,0))) sl
+
+fun longest_string1 sl =
+	foldl (fn (s, acc) => if String.size(s) > String.size(acc)
+						   then s
+						   else acc) "" sl
+
+fun longest_string2 sl =
+	foldl (fn (s, acc) => if String.size(s) >= String.size(acc)
+						   then s
+						   else acc) "" sl
+
+fun longest_string_helper comparison sl =
+	foldl (fn (s, acc) => if comparison(String.size(s) , String.size(acc))
+						   then s
+						   else acc) "" sl
+
+val longest_string3 = 
+	longest_string_helper (fn (i1, i2) => i1>i2)
+
+val longest_string4 = 
+	longest_string_helper (fn (i1, i2) => i1>=i2)
+
+val longest_capitalized = 
+	longest_string3 o only_capitals
+
+val rev_string = String.implode o rev o String.explode
+
+
+
+
+fun first_answer operation list =
+	case list of
+		[] 	   => raise NoAnswer
+	|	hd::tl => case operation hd of
+  					  SOME v => v
+				  |	  NONE   => first_answer operation tl
+
+fun all_answers operation list =
+	let
+		fun helper acc list =
+			case list of
+				[] 	   => SOME acc
+			|	hd::tl => case operation hd of
+							  NONE   => NONE
+						  |   SOME ans => helper (acc@ans) tl
+	in
+		helper [] list
+	end
+
+
+val count_wildcards = g (fn _ => 1) (fn _ => 0)
+
+val count_wild_and_variable_lengths = g (fn _ => 1) String.size
+
+fun count_some_var (s, p) = 
+	g (fn _ => 0) (fn x => if x = s then 1 else 0) p
+
+fun check_pat p =
+	let fun get_string_list p =
+			case p of
+			  Variable s => [s]
+			| TupleP pattern_list => List.foldl (fn (p,i) => (get_string_list p) @ i) [] pattern_list
+			| ConstructorP(s, pt) => get_string_list pt
+			| _ => []
+
+		fun exist_repetitions list_string =
+			case list_string of
+			  [] => false
+			| head::tail => List.exists (fn s => s = head) tail orelse (exist_repetitions tail)
+	in
+		not((exist_repetitions o get_string_list) p)
+	end
+
+fun match(v, p) =
+	case (v, p) of
+	  (_, Wildcard) => SOME []
+	| (v, Variable s) => SOME [(s, v)]
+	| (Unit, UnitP) => SOME []
+	| (Const x, ConstP y) => if x = y then SOME [] else NONE
+	| (Tuple valu_list, TupleP pattern_list) => if length valu_list = length pattern_list
+		then all_answers match (ListPair.zip(valu_list, pattern_list)) else NONE
+	| (Constructor(s1, v), ConstructorP(s2, p)) => if s1 = s2 then match(v,p) else NONE
+	| (_, _) => NONE
+
+fun first_match v pattern_list =
+	SOME(first_answer(fn p => match(v, p)) pattern_list) handle NoAnswer => NONE
\ No newline at end of file
-- 
2.51.2