merge fasta.Keyword into analyzer.Keyword

pkg/front_end/lib/src/fasta/scanner/keyword_state.dart

+// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library fasta.scanner.keywords;
+
+import '../../scanner/token.dart' as analyzer;
+
+import 'characters.dart' show $a, $z, $A, $Z;
+
+/**
+ * Abstract state in a state machine for scanning keywords.
+ */
+abstract class KeywordState {
+  KeywordState next(int c);
+  KeywordState nextCapital(int c);
+
+  analyzer.Keyword get keyword;
+
+  static KeywordState _KEYWORD_STATE;
+  static KeywordState get KEYWORD_STATE {
+    if (_KEYWORD_STATE == null) {
+      List<String> strings = new List<String>(analyzer.Keyword.values.length);
+      for (int i = 0; i < analyzer.Keyword.values.length; i++) {
+        strings[i] = analyzer.Keyword.values[i].syntax;
+      }
+      strings.sort((a, b) => a.compareTo(b));
+      _KEYWORD_STATE = computeKeywordStateTable(0, strings, 0, strings.length);
+    }
+    return _KEYWORD_STATE;
+  }
+
+  static KeywordState computeKeywordStateTable(
+      int start, List<String> strings, int offset, int length) {
+    bool isLowercase = true;
+
+    List<KeywordState> table = new List<KeywordState>($z - $A + 1);
+    assert(length != 0);
+    int chunk = 0;
+    int chunkStart = -1;
+    bool isLeaf = false;
+    for (int i = offset; i < offset + length; i++) {
+      if (strings[i].length == start) {
+        isLeaf = true;
+      }
+      if (strings[i].length > start) {
+        int c = strings[i].codeUnitAt(start);
+        if ($A <= c && c <= $Z) {
+          isLowercase = false;
+        }
+        if (chunk != c) {
+          if (chunkStart != -1) {
+            assert(table[chunk - $A] == null);
+            table[chunk - $A] = computeKeywordStateTable(
+                start + 1, strings, chunkStart, i - chunkStart);
+          }
+          chunkStart = i;
+          chunk = c;
+        }
+      }
+    }
+    if (chunkStart != -1) {
+      assert(table[chunk - $A] == null);
+      table[chunk - $A] = computeKeywordStateTable(
+          start + 1, strings, chunkStart, offset + length - chunkStart);
+    } else {
+      assert(length == 1);
+      return new LeafKeywordState(strings[offset]);
+    }
+    String syntax = isLeaf ? strings[offset] : null;
+    if (isLowercase) {
+      table = table.sublist($a - $A);
+      return new LowerCaseArrayKeywordState(table, syntax);
+    } else {
+      return new UpperCaseArrayKeywordState(table, syntax);
+    }
+  }
+}
+
+/**
+ * A state with multiple outgoing transitions.
+ */
+abstract class ArrayKeywordState implements KeywordState {
+  final List<KeywordState> table;
+  final analyzer.Keyword keyword;
+
+  ArrayKeywordState(this.table, String syntax)
+      : keyword = ((syntax == null) ? null : analyzer.Keyword.keywords[syntax]);
+
+  KeywordState next(int c);
+
+  KeywordState nextCapital(int c);
+
+  String toString() {
+    StringBuffer sb = new StringBuffer();
+    sb.write("[");
+    if (keyword != null) {
+      sb.write("*");
+      sb.write(keyword);
+      sb.write(" ");
+    }
+    List<KeywordState> foo = table;
+    for (int i = 0; i < foo.length; i++) {
+      if (foo[i] != null) {
+        sb.write("${new String.fromCharCodes([i + $a])}: "
+            "${foo[i]}; ");
+      }
+    }
+    sb.write("]");
+    return sb.toString();
+  }
+}
+
+class LowerCaseArrayKeywordState extends ArrayKeywordState {
+  LowerCaseArrayKeywordState(List<KeywordState> table, String syntax)
+      : super(table, syntax) {
+    assert(table.length == $z - $a + 1);
+  }
+
+  KeywordState next(int c) => table[c - $a];
+
+  KeywordState nextCapital(int c) => null;
+}
+
+class UpperCaseArrayKeywordState extends ArrayKeywordState {
+  UpperCaseArrayKeywordState(List<KeywordState> table, String syntax)
+      : super(table, syntax) {
+    assert(table.length == $z - $A + 1);
+  }
+
+  KeywordState next(int c) => table[c - $A];
+
+  KeywordState nextCapital(int c) => table[c - $A];
+}
+
+/**
+ * A state that has no outgoing transitions.
+ */
+class LeafKeywordState implements KeywordState {
+  final analyzer.Keyword keyword;
+
+  LeafKeywordState(String syntax) : keyword = analyzer.Keyword.keywords[syntax];
+
+  KeywordState next(int c) => null;
+  KeywordState nextCapital(int c) => null;
+
+  String toString() => keyword.syntax;
+}