Use single quotes.

Author: lrhn

pkgs/characters/analysis_options.yaml

@@ -1,5 +1 @@
 include: package:dart_flutter_team_lints/analysis_options.yaml
-
-analyzer:
-  errors:
-    prefer_single_quotes: ignore

pkgs/characters/benchmark/benchmark.dart

@@ -4,9 +4,9 @@
 
 // Benchmark of efficiency of grapheme cluster operations.
 
-import "package:characters/characters.dart";
+import 'package:characters/characters.dart';
 
-import "../test/src/text_samples.dart";
+import '../test/src/text_samples.dart';
 
 double bench(int Function() action, int ms) {
   var elapsed = 0;
@@ -49,12 +49,12 @@ int reverseStrings() {
   var revHangul = reverse(hangul);
   var rev2Hangul = reverse(revHangul);
   if (hangul != rev2Hangul || hangul == revHangul) {
-    throw AssertionError("Bad reverse");
+    throw AssertionError('Bad reverse');
   }
   var revGenesis = reverse(genesis);
   var rev2Genesis = reverse(revGenesis);
   if (genesis != rev2Genesis || genesis == revGenesis) {
-    throw AssertionError("Bad reverse");
+    throw AssertionError('Bad reverse');
   }
 
   return (hangul.length + genesis.length) * 2;
@@ -63,16 +63,16 @@ int reverseStrings() {
 int replaceStrings() {
   var count = 0;
   {
-    const language = "한글";
+    const language = '한글';
     assert(language.length == 6);
     var chars = Characters(hangul);
     var replaced =
-        chars.replaceAll(Characters(language), Characters("Hangul!"));
+        chars.replaceAll(Characters(language), Characters('Hangul!'));
     count += replaced.string.length - hangul.length;
   }
   {
     var chars = Characters(genesis);
-    var replaced = chars.replaceAll(Characters("And"), Characters("Also"));
+    var replaced = chars.replaceAll(Characters('And'), Characters('Also'));
     count += replaced.string.length - genesis.length;
   }
   return count;
@@ -111,27 +111,27 @@ void main(List<String> args) {
 
   for (var i = 0; i < count; i++) {
     var performance = bench(iterateIndicesOnly, 2000);
-    print("Index Iteration: ${toDigits(performance)} gc/ms");
+    print('Index Iteration: ${toDigits(performance)} gc/ms');
     if (performance > bestIterateIndices) bestIterateIndices = performance;
 
     performance = bench(iterateStrings, 2000);
-    print("String Iteration: ${toDigits(performance)} cu/ms");
+    print('String Iteration: ${toDigits(performance)} cu/ms');
     if (performance > bestIterateStrings) bestIterateStrings = performance;
 
     performance = bench(reverseStrings, 2000);
-    print("String Reversing: ${toDigits(performance)} cu/ms");
+    print('String Reversing: ${toDigits(performance)} cu/ms');
     if (performance > bestReverseStrings) bestReverseStrings = performance;
 
     performance = bench(replaceStrings, 2000);
-    print("String Replacing: ${toDigits(performance)} changes/ms");
+    print('String Replacing: ${toDigits(performance)} changes/ms');
     if (performance > bestReplaceStrings) bestReplaceStrings = performance;
   }
 
   if (count > 1) {
-    print("Best: ");
-    print("Index Iteration: ${toDigits(bestIterateIndices)} gc/ms");
-    print("String Iteration: ${toDigits(bestIterateStrings)} cu/ms");
-    print("String Reversing: ${toDigits(bestReverseStrings)} cu/ms");
-    print("String Replacing: ${toDigits(bestReplaceStrings)} changes/ms");
+    print('Best: ');
+    print('Index Iteration: ${toDigits(bestIterateIndices)} gc/ms');
+    print('String Iteration: ${toDigits(bestIterateStrings)} cu/ms');
+    print('String Reversing: ${toDigits(bestReverseStrings)} cu/ms');
+    print('String Replacing: ${toDigits(bestReplaceStrings)} changes/ms');
   }
 }

pkgs/characters/lib/characters.dart

@@ -5,5 +5,5 @@
 /// String operations based on characters (Unicode grapheme clusters).
 library;
 
-export "src/characters.dart";
-export "src/extensions.dart";
+export 'src/characters.dart';
+export 'src/extensions.dart';

pkgs/characters/lib/src/characters.dart

@@ -2,7 +2,7 @@
 // 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.
 
-import "characters_impl.dart";
+import 'characters_impl.dart';
 
 /// The characters of a string.
 ///
@@ -21,7 +21,7 @@ import "characters_impl.dart";
 /// in different ways.
 abstract class Characters implements Iterable<String> {
   /// An empty [Characters] containing no characters.
-  static const Characters empty = StringCharacters("");
+  static const Characters empty = StringCharacters('');
 
   /// Creates a [Characters] allowing iteration of
   /// the characters of [string].
@@ -260,9 +260,9 @@ abstract class Characters implements Iterable<String> {
   /// Any further occurrences will be included in the last part.
   /// Example:
   /// ```dart
-  /// var c = "abracadabra".characters;
-  /// var parts = c.split("a".characters, 4).toList();
-  /// print(parts); // Prints is ["", "br", "c", "dabra"]
+  /// var c = 'abracadabra'.characters;
+  /// var parts = c.split('a'.characters, 4).toList();
+  /// print(parts); // Prints is ['', 'br', 'c', 'dabra']
   /// ```
   /// If there are fewer than `maxParts - 1` occurrences of [pattern],
   /// then the characters are split at all occurrences.
@@ -790,9 +790,9 @@ abstract class CharacterRange implements Iterator<String> {
   ///
   /// Example:
   /// ```dart
-  /// var c = "abracadabra".characters.dropFirst().dropLast();
-  /// // c is "bracadabr".
-  /// var parts = c.split("a".characters, 3).toList();
+  /// var c = 'abracadabra'.characters.dropFirst().dropLast();
+  /// // c is 'bracadabr'.
+  /// var parts = c.split('a'.characters, 3).toList();
   /// print(parts); // [br, c, dabr]
   /// ```
   /// If there are fewer than `maxParts - 1` occurrences of [pattern],

pkgs/characters/lib/src/characters_impl.dart

@@ -2,9 +2,9 @@
 // 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.
 
-import "characters.dart";
-import "grapheme_clusters/breaks.dart";
-import "grapheme_clusters/constants.dart";
+import 'characters.dart';
+import 'grapheme_clusters/breaks.dart';
+import 'grapheme_clusters/constants.dart';
 import 'grapheme_clusters/table.dart';
 
 /// The grapheme clusters of a string.
@@ -28,23 +28,23 @@ final class StringCharacters extends Iterable<String> implements Characters {
 
   @override
   String get first => string.isEmpty
-      ? throw StateError("No element")
+      ? throw StateError('No element')
       : string.substring(
           0, Breaks(string, 0, string.length, stateSoTNoBreak).nextBreak());
 
   @override
   String get last => string.isEmpty
-      ? throw StateError("No element")
+      ? throw StateError('No element')
       : string.substring(
           BackBreaks(string, string.length, 0, stateEoTNoBreak).nextBreak());
 
   @override
   String get single {
-    if (string.isEmpty) throw StateError("No element");
+    if (string.isEmpty) throw StateError('No element');
     var firstEnd =
         Breaks(string, 0, string.length, stateSoTNoBreak).nextBreak();
     if (firstEnd == string.length) return string;
-    throw StateError("Too many elements");
+    throw StateError('Too many elements');
   }
 
   @override
@@ -74,9 +74,9 @@ final class StringCharacters extends Iterable<String> implements Characters {
   }
 
   @override
-  String join([String separator = ""]) {
-    if (separator == "") return string;
-    return _explodeReplace(string, 0, string.length, separator, "");
+  String join([String separator = '']) {
+    if (separator == '') return string;
+    return _explodeReplace(string, 0, string.length, separator, '');
   }
 
   @override
@@ -91,12 +91,12 @@ final class StringCharacters extends Iterable<String> implements Characters {
       cursor = next;
     }
     if (orElse != null) return orElse();
-    throw StateError("No element");
+    throw StateError('No element');
   }
 
   @override
   String elementAt(int index) {
-    RangeError.checkNotNegative(index, "index");
+    RangeError.checkNotNegative(index, 'index');
     var count = 0;
     if (string.isNotEmpty) {
       var breaks = Breaks(string, 0, string.length, stateSoTNoBreak);
@@ -108,7 +108,7 @@ final class StringCharacters extends Iterable<String> implements Characters {
         start = end;
       }
     }
-    throw RangeError.index(index, this, "index", null, count);
+    throw RangeError.index(index, this, 'index', null, count);
   }
 
   @override
@@ -209,7 +209,7 @@ final class StringCharacters extends Iterable<String> implements Characters {
 
   @override
   Characters skip(int count) {
-    RangeError.checkNotNegative(count, "count");
+    RangeError.checkNotNegative(count, 'count');
     return _skip(count);
   }
 
@@ -221,7 +221,7 @@ final class StringCharacters extends Iterable<String> implements Characters {
 
   @override
   Characters take(int count) {
-    RangeError.checkNotNegative(count, "count");
+    RangeError.checkNotNegative(count, 'count');
     return _take(count);
   }
 
@@ -233,9 +233,9 @@ final class StringCharacters extends Iterable<String> implements Characters {
 
   @override
   Characters getRange(int start, [int? end]) {
-    RangeError.checkNotNegative(start, "start");
+    RangeError.checkNotNegative(start, 'start');
     if (end == null) return _skip(start);
-    if (end < start) throw RangeError.range(end, start, null, "end");
+    if (end < start) throw RangeError.range(end, start, null, 'end');
     if (end == start) return Characters.empty;
     if (start == 0) return _take(end);
     if (string.isEmpty) return this;
@@ -254,10 +254,10 @@ final class StringCharacters extends Iterable<String> implements Characters {
     while (position > 0) {
       position--;
       start = breaks.nextBreak();
-      if (start < 0) throw StateError("No element");
+      if (start < 0) throw StateError('No element');
     }
     var end = breaks.nextBreak();
-    if (end < 0) throw StateError("No element");
+    if (end < 0) throw StateError('No element');
     if (start == 0 && end == string.length) return this;
     return StringCharacters(string.substring(start, end));
   }
@@ -311,7 +311,7 @@ final class StringCharacters extends Iterable<String> implements Characters {
 
   @override
   Characters skipLast(int count) {
-    RangeError.checkNotNegative(count, "count");
+    RangeError.checkNotNegative(count, 'count');
     if (count == 0) return this;
     if (string.isNotEmpty) {
       var breaks = BackBreaks(string, string.length, 0, stateEoTNoBreak);
@@ -351,7 +351,7 @@ final class StringCharacters extends Iterable<String> implements Characters {
 
   @override
   Characters takeLast(int count) {
-    RangeError.checkNotNegative(count, "count");
+    RangeError.checkNotNegative(count, 'count');
     if (count == 0) return Characters.empty;
     if (string.isNotEmpty) {
       var breaks = BackBreaks(string, string.length, 0, stateEoTNoBreak);
@@ -446,7 +446,7 @@ class StringCharacterRange implements CharacterRange {
   factory StringCharacterRange.at(String string, int startIndex,
       [int? endIndex]) {
     RangeError.checkValidRange(
-        startIndex, endIndex, string.length, "startIndex", "endIndex");
+        startIndex, endIndex, string.length, 'startIndex', 'endIndex');
     return _expandRange(string, startIndex, endIndex ?? startIndex);
   }
 
@@ -513,7 +513,7 @@ class StringCharacterRange implements CharacterRange {
       _move(newStart, _end);
       return true;
     } else {
-      throw RangeError.range(count, 0, null, "count");
+      throw RangeError.range(count, 0, null, 'count');
     }
   }
 
@@ -530,7 +530,7 @@ class StringCharacterRange implements CharacterRange {
   bool moveBack([int count = 1]) => _retractStart(count, _start);
 
   bool _retractStart(int count, int newEnd) {
-    RangeError.checkNotNegative(count, "count");
+    RangeError.checkNotNegative(count, 'count');
     var breaks = _backBreaksFromStart();
     var start = _start;
     while (count > 0) {
@@ -578,7 +578,7 @@ class StringCharacterRange implements CharacterRange {
 
   @override
   bool dropFirst([int count = 1]) {
-    RangeError.checkNotNegative(count, "count");
+    RangeError.checkNotNegative(count, 'count');
     if (_start == _end) return count == 0;
     var breaks = Breaks(_string, _start, _end, stateSoTNoBreak);
     while (count > 0) {
@@ -636,7 +636,7 @@ class StringCharacterRange implements CharacterRange {
 
   @override
   bool dropLast([int count = 1]) {
-    RangeError.checkNotNegative(count, "count");
+    RangeError.checkNotNegative(count, 'count');
     var breaks = BackBreaks(_string, _end, _start, stateEoTNoBreak);
     while (count > 0) {
       var nextBreak = breaks.nextBreak();

pkgs/characters/lib/src/grapheme_clusters/breaks.dart

@@ -8,8 +8,8 @@
 
 library;
 
-import "constants.dart";
-import "table.dart";
+import 'constants.dart';
+import 'table.dart';
 
 /// Iterates grapheme cluster breaks of a string.
 ///
@@ -21,7 +21,7 @@ import "table.dart";
 /// var breaks = Breaks(string, start, end, stateSoT);
 /// int brk = 0;
 /// while((brk = breaks.nextBreak) >= 0) {
-///   print("Break at index $brk");
+///   print('Break at index $brk');
 /// }
 /// ```
 /// If you use [stateSoTNoBreak] instead of [stateSoT], the
@@ -153,7 +153,7 @@ class Breaks {
 /// var breaks = BackBreaks(string, start, end, idStateEoT);
 /// int brk = 0;
 /// while ((brk = breaks.nextBreak()) >= 0) {
-///   print("Break at index $brk");
+///   print('Break at index $brk');
 /// }
 /// ```
 /// If the initial [state] is [stateEoTNoBreak] instead of [stateEoT],