Made candidate cache and using itertools.permutations

candidate_cache.py

@@ -0,0 +1,36 @@
+import itertools
+from dictionary import Dictionary, DICTS
+
+
+def make_key(dictionary_name, letters):
+    return (dictionary_name, frozenset(letters))
+
+
+def candidates(letters, dictionary: Dictionary, min=2):
+    permutations = itertools.chain.from_iterable(
+        map(lambda r: itertools.permutations(letters, r), range(min, len(letters) + 1))
+    )
+    return dictionary.filter(map("".join, permutations))
+
+
+class CandidateCache:
+    def __init__(self, maxsize=5):
+        self.maxsize = maxsize
+        self.cache = {}
+        self.keys = []
+
+    def get(self, dictionary_name, letters):
+        key = make_key(dictionary_name, letters)
+        try:
+            return self.cache[key]
+        except KeyError:
+            data = candidates(letters, DICTS[dictionary_name])
+            self.create(key, data)
+            return data
+
+    def create(self, key, data):
+        if len(self.keys) > self.maxsize:
+            key = self.keys.pop()
+            del self.cache[key]
+        self.keys.insert(0, key)
+        self.cache[key] = data

dictionary.py

@@ -54,3 +54,4 @@ class Dictionary:
 
 DEFAULT = Dictionary(default_load_future)
 ALTERNATE = Dictionary(alternate_load_future)
+DICTS = {"default": DEFAULT, "alt": ALTERNATE}

main.py

@@ -1,19 +1,18 @@
 #!/usr/bin/python3
 from string import ascii_lowercase
 import argparse
-import itertools
 import os
 import re
 
 import cmd2
 
-
-from dictionary import DEFAULT, ALTERNATE
+from candidate_cache import CandidateCache
+from dictionary import DICTS
 from word_remove_dialog import RemoveWordsActivity
 
 
 LOWERCASE = set(ascii_lowercase)
-DICTS = {"default": DEFAULT, "alt": ALTERNATE}
+
 # argparsers
 dictionary_manage_parser = argparse.ArgumentParser()
 commands = dictionary_manage_parser.add_mutually_exclusive_group(required=True)
@@ -47,16 +46,6 @@ commands.add_argument(
 )
 
 
-def candidates(letters, min=2):
-    possibilities = []
-    for length in range(min, len(letters) + 1):
-        for comb in itertools.combinations(letters, length):
-            for perm in itertools.permutations(comb):
-                word = "".join(perm)
-                possibilities.append(word)
-    return possibilities
-
-
 class MainLoop(cmd2.Cmd):
     """Loop for wordscape commands
 
@@ -69,7 +58,7 @@ class MainLoop(cmd2.Cmd):
         self.excludes = set()
         self.hidden = set()
         self.init_letters(input("Enter letters: "))
-        self._candidates = None
+        self.cache = CandidateCache()
         super().__init__()
 
     def init_letters(self, letters):
@@ -78,17 +67,14 @@ class MainLoop(cmd2.Cmd):
         letters = letters.lower()
         self.letters = [l for l in letters if l in LOWERCASE]
         self.prompt = MainLoop.prompt.format(", ".join(self.letters))
-        self._candidates = None
 
     @property
     def candidates(self):
-        if self._candidates is None:
-            self._candidates = candidates(self.letters)
-        return self._candidates
+        return self.cache.get(self.dict, self.letters)
 
     def filter(self, regex):
-        matching_pattern = filter(regex.match, self.candidates)
-        return DICTS[self.dict].filter(matching_pattern)
+
+        return set(filter(regex.match, self.candidates))
 
     @cmd2.with_argparser(dictionary_manage_parser)
     def do_dict(self, args):