refactor

src/Console/Lexer/KeywordMatch.cs

@@ -0,0 +1,116 @@
+using System.Collections.Generic;
+using UnityEngine;
+
+namespace UnityExplorer.Console.Lexer
+{
+    public sealed class KeywordMatch : Matcher
+    {
+        public string keywords;
+
+        public override Color HighlightColor => highlightColor;
+        public Color highlightColor;
+
+        private readonly HashSet<string> shortlist = new HashSet<string>();
+        private readonly Stack<string> removeList = new Stack<string>();
+        public string[] keywordCache = null;
+
+        public override bool IsImplicitMatch(InputLexer lexer)
+        {
+            BuildKeywordCache();
+
+            if (!char.IsWhiteSpace(lexer.Previous) &&
+                !lexer.IsSpecialSymbol(lexer.Previous, SpecialCharacterPosition.End))
+            {
+                return false;
+            }
+
+            shortlist.Clear();
+
+            int currentIndex = 0;
+            char currentChar = lexer.ReadNext();
+
+            for (int i = 0; i < keywordCache.Length; i++)
+            {
+                if (keywordCache[i][0] == currentChar)
+                {
+                    shortlist.Add(keywordCache[i]);
+                }
+            }
+
+            if (shortlist.Count == 0)
+            {
+                return false;
+            }
+
+            do
+            {
+                if (lexer.EndOfStream)
+                {
+                    RemoveLongStrings(currentIndex + 1);
+                    break;
+                }
+
+                currentChar = lexer.ReadNext();
+                currentIndex++;
+
+                if (char.IsWhiteSpace(currentChar) ||
+                    lexer.IsSpecialSymbol(currentChar, SpecialCharacterPosition.Start))
+                {
+                    RemoveLongStrings(currentIndex);
+                    lexer.Rollback(1);
+                    break;
+                }
+
+                foreach (string keyword in shortlist)
+                {
+                    if (currentIndex >= keyword.Length || keyword[currentIndex] != currentChar)
+                    {
+                        removeList.Push(keyword);
+                    }
+                }
+
+                while (removeList.Count > 0)
+                {
+                    shortlist.Remove(removeList.Pop());
+                }
+            }
+            while (shortlist.Count > 0);
+
+            return shortlist.Count > 0;
+        }
+
+        private void RemoveLongStrings(int length)
+        {
+            foreach (string keyword in shortlist)
+            {
+                if (keyword.Length > length)
+                {
+                    removeList.Push(keyword);
+                }
+            }
+
+            while (removeList.Count > 0)
+            {
+                shortlist.Remove(removeList.Pop());
+            }
+        }
+
+        private void BuildKeywordCache()
+        {
+            if (keywordCache == null)
+            {
+                string[] kwSplit = keywords.Split(' ');
+
+                List<string> list = new List<string>();
+                foreach (string kw in kwSplit)
+                {
+                    if (!string.IsNullOrEmpty(kw) && kw.Length > 0)
+                    {
+                        list.Add(kw);
+                    }
+                }
+                keywordCache = list.ToArray();
+            }
+        }
+    }
+}