Refines filter parser logic.

Adds naming rule for type parameters.

Streamlines the filter parser by removing unnecessary checks and improving character handling within quotes. This enhances efficiency and code clarity.

The parser now throws an exception if a function that requires comparison is left as a standalone expression.

Author: bfarmer67

Hyperbee.Json.sln.DotSettings

@@ -37,6 +37,7 @@
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=PublicFields/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="AaBb"&gt;&lt;ExtraRule Prefix="_" Suffix="" Style="aaBb" /&gt;&lt;/Policy&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=TypesAndNamespaces/@EntryIndexedValue">&lt;Policy Inspect="True" Prefix="" Suffix="" Style="AaBb"&gt;&lt;ExtraRule Prefix="I" Suffix="" Style="AaBb" /&gt;&lt;/Policy&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=15b5b1f1_002D457c_002D4ca6_002Db278_002D5615aedc07d3/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Static" AccessRightKinds="Private" Description="Static readonly fields (private)"&gt;&lt;ElementKinds&gt;&lt;Kind Name="READONLY_FIELD" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="" Suffix="" Style="AaBb"&gt;&lt;ExtraRule Prefix="__" Suffix="" Style="aaBb" /&gt;&lt;/Policy&gt;&lt;/Policy&gt;</s:String>
+	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=2c62818f_002D621b_002D4425_002Dadc9_002D78611099bfcb/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Any" AccessRightKinds="Any" Description="Type parameters"&gt;&lt;ElementKinds&gt;&lt;Kind Name="TYPE_PARAMETER" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" WarnAboutPrefixesAndSuffixes="False" Prefix="" Suffix="" Style="AA_BB"&gt;&lt;ExtraRule Prefix="" Suffix="" Style="Aa_bb" /&gt;&lt;/Policy&gt;&lt;/Policy&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=4a98fdf6_002D7d98_002D4f5a_002Dafeb_002Dea44ad98c70c/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Instance" AccessRightKinds="Private" Description="Instance fields (private)"&gt;&lt;ElementKinds&gt;&lt;Kind Name="FIELD" /&gt;&lt;Kind Name="READONLY_FIELD" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="_" Suffix="" Style="aaBb"&gt;&lt;ExtraRule Prefix="" Suffix="" Style="AaBb" /&gt;&lt;/Policy&gt;&lt;/Policy&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=53eecf85_002Dd821_002D40e8_002Dac97_002Dfdb734542b84/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Instance" AccessRightKinds="Protected, ProtectedInternal, Internal, Public, PrivateProtected" Description="Instance fields (not private)"&gt;&lt;ElementKinds&gt;&lt;Kind Name="FIELD" /&gt;&lt;Kind Name="READONLY_FIELD" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="" Suffix="" Style="AaBb"&gt;&lt;ExtraRule Prefix="_" Suffix="" Style="aaBb" /&gt;&lt;/Policy&gt;&lt;/Policy&gt;</s:String>
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/UserRules/=70345118_002D4b40_002D4ece_002D937c_002Dbbeb7a0b2e70/@EntryIndexedValue">&lt;Policy&gt;&lt;Descriptor Staticness="Static" AccessRightKinds="Protected, ProtectedInternal, Internal, Public, PrivateProtected" Description="Static fields (not private)"&gt;&lt;ElementKinds&gt;&lt;Kind Name="FIELD" /&gt;&lt;/ElementKinds&gt;&lt;/Descriptor&gt;&lt;Policy Inspect="True" Prefix="" Suffix="" Style="AaBb"&gt;&lt;ExtraRule Prefix="_" Suffix="" Style="aaBb" /&gt;&lt;/Policy&gt;&lt;/Policy&gt;</s:String>

src/Hyperbee.Json/Path/Filters/Parser/FilterParser.cs

@@ -63,7 +63,6 @@ internal static Expression Parse( ref ParserState state ) // recursion entrypoin
         {
             MoveNext( ref state );
             items.Enqueue( GetExprItem( ref state ) ); // may cause recursion
-
         } while ( state.IsParsing );
 
         // check for paren mismatch
@@ -153,9 +152,7 @@ static bool IsFinished( in ParserState state, char ch, ref int itemEnd )
     private static void MoveNextOperator( ref ParserState state ) // move to the next operator
     {
         if ( state.Operator.IsLogical() || state.Operator.IsComparison() || state.Operator.IsMath() )
-        {
             return;
-        }
 
         if ( !state.IsParsing )
         {
@@ -174,6 +171,7 @@ private static void MoveNextOperator( ref ParserState state ) // move to the nex
 
     private static void NextCharacter( ref ParserState state, int start, out char nextChar, ref char? quoteChar )
     {
+        // Read next character
         nextChar = state.Buffer[state.Pos++];
 
         // Handle escape characters within quotes
@@ -453,11 +451,7 @@ private static void ThrowIfFunctionInvalidCompare( in ParserState state, ExprIte
         if ( state.IsArgument )
             return;
 
-        // Only throw if this function (which must be compared) is left as a standalone expression
-        // at the end of the filter. This ensures that filters like [?(length(@.title))] are rejected,
-        // but [?(length(@.title) > 10)] are allowed. We defer this check until EndOfBuffer to allow
-        // the function to be merged with a comparison operator if present.
-        if ( item.CompareConstraint.HasFlag( CompareConstraint.Function | CompareConstraint.MustCompare ) && !item.Operator.IsComparison() && state.EndOfBuffer )
+        if ( item.CompareConstraint.HasFlag( CompareConstraint.Function | CompareConstraint.MustCompare ) && !item.Operator.IsComparison() )
             throw new NotSupportedException( $"Function must compare: {state.Buffer.ToString()}." );
 
         if ( item.CompareConstraint.HasFlag( CompareConstraint.Function | CompareConstraint.MustNotCompare ) && item.Operator.IsComparison() )