RSCG – System.Text.RegularExpressions
RSCG – System.Text.RegularExpressions
| name | System.Text.RegularExpressions |
| nuget | https://www.nuget.org/packages/System.Text.RegularExpressions/ |
| link | https://learn.microsoft.com/en-us/dotnet/standard/base-types/regular-expression-source-generators/ |
| author | Microsoft |
Regex compiled
This is how you can use System.Text.RegularExpressions .
The code that you start with is
01 02 03 04 05 06 07 08 09 10 11 12 13 14 | <Project Sdk="Microsoft.NET.Sdk"> <PropertyGroup> <OutputType>Exe</OutputType> <TargetFramework>net7.0</TargetFramework> <ImplicitUsings>enable</ImplicitUsings> <Nullable>enable</Nullable> </PropertyGroup> <PropertyGroup> <EmitCompilerGeneratedFiles>true</EmitCompilerGeneratedFiles> <CompilerGeneratedFilesOutputPath>$(BaseIntermediateOutputPath)\GeneratedX</CompilerGeneratedFilesOutputPath> </PropertyGroup></Project> |
The code that you will use is
1 2 3 4 5 | using Demo;var x = "Abc";Console.WriteLine(DemoRegex.EvaluateText(x)); |
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 | using System.Text.RegularExpressions;namespace Demo;public partial class DemoRegex{ [GeneratedRegex("abc|def", RegexOptions.IgnoreCase, "en-US")] private static partial Regex AbcOrDefGeneratedRegex(); public static bool EvaluateText(string text) { return (AbcOrDefGeneratedRegex().IsMatch(text)); }} |
The code that is generated is
001 002 003 004 005 006 007 008 009 010 011 012 013 014 015 016 017 018 019 020 021 022 023 024 025 026 027 028 029 030 031 032 033 034 035 036 037 038 039 040 041 042 043 044 045 046 047 048 049 050 051 052 053 054 055 056 057 058 059 060 061 062 063 064 065 066 067 068 069 070 071 072 073 074 075 076 077 078 079 080 081 082 083 084 085 086 087 088 089 090 091 092 093 094 095 096 097 098 099 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 | // <auto-generated/>#nullable enable#pragma warning disable CS0162 // Unreachable code#pragma warning disable CS0164 // Unreferenced label#pragma warning disable CS0219 // Variable assigned but never usednamespace Demo{ partial class DemoRegex { /// <remarks> /// Pattern explanation:<br/> /// <code> /// ○ Match with 2 alternative expressions, atomically.<br/> /// ○ Match a sequence of expressions.<br/> /// ○ Match a character in the set [Aa].<br/> /// ○ Match a character in the set [Bb].<br/> /// ○ Match a character in the set [Cc].<br/> /// ○ Match a sequence of expressions.<br/> /// ○ Match a character in the set [Dd].<br/> /// ○ Match a character in the set [Ee].<br/> /// ○ Match a character in the set [Ff].<br/> /// </code> /// </remarks> [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Text.RegularExpressions.Generator", "7.0.8.17405")] private static partial global::System.Text.RegularExpressions.Regex AbcOrDefGeneratedRegex() => global::System.Text.RegularExpressions.Generated.AbcOrDefGeneratedRegex_0.Instance; }}namespace System.Text.RegularExpressions.Generated{ using System; using System.CodeDom.Compiler; using System.Collections; using System.ComponentModel; using System.Globalization; using System.Runtime.CompilerServices; using System.Text.RegularExpressions; using System.Threading; /// <summary>Custom <see cref="Regex"/>-derived type for the AbcOrDefGeneratedRegex method.</summary> [GeneratedCodeAttribute("System.Text.RegularExpressions.Generator", "7.0.8.17405")] file sealed class AbcOrDefGeneratedRegex_0 : Regex { /// <summary>Cached, thread-safe singleton instance.</summary> internal static readonly AbcOrDefGeneratedRegex_0 Instance = new(); /// <summary>Initializes the instance.</summary> private AbcOrDefGeneratedRegex_0() { base.pattern = "abc|def"; base.roptions = RegexOptions.IgnoreCase; ValidateMatchTimeout(Utilities.s_defaultTimeout); base.internalMatchTimeout = Utilities.s_defaultTimeout; base.factory = new RunnerFactory(); base.capsize = 1; } /// <summary>Provides a factory for creating <see cref="RegexRunner"/> instances to be used by methods on <see cref="Regex"/>.</summary> private sealed class RunnerFactory : RegexRunnerFactory { /// <summary>Creates an instance of a <see cref="RegexRunner"/> used by methods on <see cref="Regex"/>.</summary> protected override RegexRunner CreateInstance() => new Runner(); /// <summary>Provides the runner that contains the custom logic implementing the specified regular expression.</summary> private sealed class Runner : RegexRunner { /// <summary>Scan the <paramref name="inputSpan"/> starting from base.runtextstart for the next match.</summary> /// <param name="inputSpan">The text being scanned by the regular expression.</param> protected override void Scan(ReadOnlySpan<char> inputSpan) { // Search until we can't find a valid starting position, we find a match, or we reach the end of the input. while (TryFindNextPossibleStartingPosition(inputSpan) && !TryMatchAtCurrentPosition(inputSpan) && base.runtextpos != inputSpan.Length) { base.runtextpos++; if (Utilities.s_hasTimeout) { base.CheckTimeout(); } } } /// <summary>Search <paramref name="inputSpan"/> starting from base.runtextpos for the next location a match could possibly start.</summary> /// <param name="inputSpan">The text being scanned by the regular expression.</param> /// <returns>true if a possible match was found; false if no more matches are possible.</returns> private bool TryFindNextPossibleStartingPosition(ReadOnlySpan<char> inputSpan) { int pos = base.runtextpos; ulong charMinusLow; // Any possible match is at least 3 characters. if (pos <= inputSpan.Length - 3) { // The pattern matches a character in the set [CFcf] at index 2. // Find the next occurrence. If it can't be found, there's no match. ReadOnlySpan<char> span = inputSpan.Slice(pos); for (int i = 0; i < span.Length - 2; i++) { int indexOfPos = span.Slice(i + 2).IndexOfAny("CFcf"); if (indexOfPos < 0) { goto NoMatchFound; } i += indexOfPos; if (((long)((0x9000000090000000UL << (int)(charMinusLow = (uint)span[i] - 'A')) & (charMinusLow - 64)) < 0) && ((long)((0x9000000090000000UL << (int)(charMinusLow = (uint)span[i + 1] - 'B')) & (charMinusLow - 64)) < 0)) { base.runtextpos = pos + i; return true; } } } // No match found. NoMatchFound: base.runtextpos = inputSpan.Length; return false; } /// <summary>Determine whether <paramref name="inputSpan"/> at base.runtextpos is a match for the regular expression.</summary> /// <param name="inputSpan">The text being scanned by the regular expression.</param> /// <returns>true if the regular expression matches at the current position; otherwise, false.</returns> private bool TryMatchAtCurrentPosition(ReadOnlySpan<char> inputSpan) { int pos = base.runtextpos; int matchStart = pos; ReadOnlySpan<char> slice = inputSpan.Slice(pos); // Match with 2 alternative expressions, atomically. { if (slice.IsEmpty) { return false; // The input didn't match. } switch (slice[0]) { case 'A' or 'a': if ((uint)slice.Length < 3 || !slice.Slice(1).StartsWith("bc", StringComparison.OrdinalIgnoreCase)) // Match the string "bc" (ordinal case-insensitive) { return false; // The input didn't match. } pos += 3; slice = inputSpan.Slice(pos); break; case 'D' or 'd': if ((uint)slice.Length < 3 || !slice.Slice(1).StartsWith("ef", StringComparison.OrdinalIgnoreCase)) // Match the string "ef" (ordinal case-insensitive) { return false; // The input didn't match. } pos += 3; slice = inputSpan.Slice(pos); break; default: return false; // The input didn't match. } } // The input matched. base.runtextpos = pos; base.Capture(0, matchStart, pos); return true; } } } } /// <summary>Helper methods used by generated <see cref="Regex"/>-derived implementations.</summary> [GeneratedCodeAttribute("System.Text.RegularExpressions.Generator", "7.0.8.17405")] file static class Utilities { /// <summary>Default timeout value set in <see cref="AppContext"/>, or <see cref="Regex.InfiniteMatchTimeout"/> if none was set.</summary> internal static readonly TimeSpan s_defaultTimeout = AppContext.GetData("REGEX_DEFAULT_MATCH_TIMEOUT") is TimeSpan timeout ? timeout : Regex.InfiniteMatchTimeout; /// <summary>Whether <see cref="s_defaultTimeout"/> is non-infinite.</summary> internal static readonly bool s_hasTimeout = s_defaultTimeout != Timeout.InfiniteTimeSpan; }} |
Code and pdf at
https://ignatandrei.github.io/RSCG_Examples/v2/docs/System.Text.RegularExpressions
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