Make liquid tag optional to improve parsing performance

Directory.Packages.props

@@ -11,12 +11,12 @@
     <PackageVersion Include="Microsoft.Extensions.FileProviders.Abstractions" Version="$(MicrosoftExtensionsFileProvidersAbstractionsPackageVersion)" />
 
     <!-- Only used with netstandard2.0 -->
-    <PackageVersion Include="System.Text.Json" Version="$(SystemTextJsonPackageVersion)" />
+    <PackageVersion Include="System.Text.Json" Version="9.0.3" />
     <PackageVersion Include="Microsoft.CSharp" Version="4.7.0" />
     <PackageVersion Include="System.Reflection.Emit.Lightweight" Version="4.7.0" />
 
     <!-- Common to all TFMs -->
-    <PackageVersion Include="Parlot" Version="1.3.3" />
+    <PackageVersion Include="Parlot" Version="1.3.5" />
     <PackageVersion Include="TimeZoneConverter" Version="7.0.0" />
 
     <!-- Benchmarks -->

Fluid.Tests/ParserTests.cs

@@ -987,7 +987,8 @@ public void ShouldParseLiquidTag()
     | upcase 
 %}";
 
-            Assert.True(_parser.TryParse(source, out var template, out var errors), errors);
+            var parser = new FluidParser(new FluidParserOptions { AllowLiquidTag = true });
+            Assert.True(parser.TryParse(source, out var template, out var errors), errors);
             var rendered = template.Render();
             Assert.Contains("WELCOME TO THE LIQUID TAG", rendered);
         }
@@ -1003,7 +1004,8 @@ public void ShouldParseLiquidTagWithBlocks()
 %}
 ";
 
-            Assert.True(_parser.TryParse(source, out var template, out var errors), errors);
+            var parser = new FluidParser(new FluidParserOptions { AllowLiquidTag = true });
+            Assert.True(parser.TryParse(source, out var template, out var errors), errors);
             var rendered = template.Render();
             Assert.Contains("WELCOME TO THE LIQUID TAG", rendered);
         }
@@ -1091,11 +1093,11 @@ public void ShouldParseLiquidTagWithDifferentSpaces(string spaces)
                 {% liquid
                     for c in (1..3)
                         echo c
-                    endforSPACE%}SPACE{{chars}}SPACE
-                """.Replace("SPACE", spaces);
+                    endfor[SPACE]%}[SPACE]{{chars}}[SPACE]
+                """.Replace("[SPACE]", spaces);
 
-            var _parser = new FluidParser();
-            Assert.True(_parser.TryParse(source, out var template, out var errors), errors);
+            var parser = new FluidParser(new FluidParserOptions { AllowLiquidTag = true });
+            Assert.True(parser.TryParse(source, out var template, out var errors), errors);
             var rendered = template.Render();
             Assert.Contains("123", rendered);
         }

Fluid/FluidParser.cs

@@ -56,11 +56,25 @@ public class FluidParser
         protected readonly Deferred<IReadOnlyList<Statement>> KnownTagsList = Deferred<IReadOnlyList<Statement>>();
         protected readonly Deferred<IReadOnlyList<Statement>> AnyTagsList = Deferred<IReadOnlyList<Statement>>();
 
-        protected static readonly Parser<TagResult> OutputStart = TagParsers.OutputTagStart();
-        protected static readonly Parser<TagResult> OutputEnd = TagParsers.OutputTagEnd(true);
-        protected static readonly Parser<TagResult> TagStart = TagParsers.TagStart();
-        protected static readonly Parser<TagResult> TagStartSpaced = TagParsers.TagStart(true);
-        protected static readonly Parser<TagResult> TagEnd = TagParsers.TagEnd(true);
+        internal const string WhiteSpaceChars = "\t\n\v\f\r \u0085             \u2028\u2029  　";
+
+        protected static readonly Parser<TagResult> InlineOutputStart = TagParsers.OutputTagStart();
+        protected static readonly Parser<TagResult> InlineOutputEnd = TagParsers.OutputTagEnd();
+        protected static readonly Parser<TagResult> InlineTagStart = TagParsers.TagStart();
+        protected static readonly Parser<TagResult> InlineTagEnd = TagParsers.TagEnd();
+
+        protected static readonly Parser<TagResult> NoInlineOutputStart = NonInlineLiquidTagParsers.OutputTagStart();
+        protected static readonly Parser<TagResult> NoInlineOutputEnd = Literals.AnyOf(WhiteSpaceChars, minSize: 0).SkipAnd(NonInlineLiquidTagParsers.OutputTagEnd());
+        protected static readonly Parser<TagResult> NoInlineTagStart = NonInlineLiquidTagParsers.TagStart();
+        protected static readonly Parser<TagResult> NoInlineTagEnd = Literals.AnyOf(WhiteSpaceChars, minSize: 0).SkipAnd(NonInlineLiquidTagParsers.TagEnd());
+
+        protected readonly Parser<TagResult> OutputStart = InlineOutputStart;
+        protected readonly Parser<TagResult> OutputEnd = InlineOutputEnd;
+        protected readonly Parser<TagResult> TagStart = InlineTagStart;
+        protected readonly Parser<TagResult> TagEnd = InlineTagEnd;
+
+        protected static readonly Parser<TagResult> RawOutputStart = NonInlineLiquidTagParsers.OutputTagStart();
+        protected static readonly Parser<TagResult> RawTagStart = NonInlineLiquidTagParsers.TagStart();
 
         protected static readonly LiteralExpression EmptyKeyword = new LiteralExpression(EmptyValue.Instance);
         protected static readonly LiteralExpression BlankKeyword = new LiteralExpression(BlankValue.Instance);
@@ -73,6 +87,14 @@ public FluidParser() : this(new())
 
         public FluidParser(FluidParserOptions parserOptions)
         {
+            if (!parserOptions.AllowLiquidTag)
+            {
+                OutputStart = NoInlineOutputStart;
+                OutputEnd = NoInlineOutputEnd;
+                TagStart = NoInlineTagStart;
+                TagEnd = NoInlineTagEnd;
+            }
+
             String.Name = "String";
             Number.Name = "Number";
 
@@ -574,7 +596,7 @@ public FluidParser(FluidParserOptions parserOptions)
             Grammar = KnownTagsList;
         }
 
-        public static Parser<string> CreateTag(string tagName) => TagStart.SkipAnd(Terms.Text(tagName)).AndSkip(TagEnd);
+        public Parser<string> CreateTag(string tagName) => TagStart.SkipAnd(Terms.Text(tagName)).AndSkip(TagEnd);
 
         public void RegisterIdentifierTag(string tagName, Func<string, TextWriter, TextEncoder, TemplateContext, ValueTask<Completion>> render)
         {

Fluid/FluidParserOptions.cs

@@ -14,5 +14,10 @@ public class FluidParserOptions
         /// Gets whether parentheses are allowed in templates. Default is <c>false</c>.
         /// </summary>
         public bool AllowParentheses { get; set; }
+
+        /// <summary>
+        /// Gets whether the inline liquid tag is allowed in templates. Default is <c>false</c>.
+        /// </summary>
+        public bool AllowLiquidTag { get; set; }
     }
 }