Simplified coordination between the parser and simulation.

Author: RyanLamansky

SqlServerSimulator/Parser/ParserContext.cs

@@ -1,6 +1,7 @@
 using SqlServerSimulator.Parser.Tokens;
 using System.Collections.Frozen;
 using System.Data.Common;
+using System.Diagnostics.CodeAnalysis;
 
 namespace SqlServerSimulator.Parser;
 
@@ -80,7 +81,7 @@ public void MoveNextOptional()
     public Token GetNextRequired()
     {
         var previous = this.Token;
-        return MoveNext() ? this.Token! : throw SimulatedSqlException.SyntaxErrorNear(previous);
+        return MoveNext() ? this.Token : throw SimulatedSqlException.SyntaxErrorNear(previous);
     }
 
     /// <summary>
@@ -131,7 +132,8 @@ public void MoveNextRequired()
     /// <see cref="index"/> is updated to the position of the next token.
     /// </remarks>
     /// <returns>True if another token was found, otherwise false.</returns>
-    private bool MoveNext()
+    [MemberNotNullWhen(true, nameof(Token))]
+    public bool MoveNext()
     {
         while (Tokenizer.NextToken(commandText, ref index) is Token token)
         {

SqlServerSimulator/Simulation.cs

@@ -32,7 +32,7 @@ internal IEnumerable<SimulatedStatementOutcome> CreateResultSetsForCommand(Simul
     {
         var context = new ParserContext(command);
 
-        while (context.GetNextOptional() is not null)
+        while (context.MoveNext())
         {
             switch (context.Token)
             {
@@ -166,7 +166,7 @@ internal IEnumerable<SimulatedStatementOutcome> CreateResultSetsForCommand(Simul
             }
 
             throw SimulatedSqlException.SyntaxErrorNear(context);
-        } // while (tokens.TryMoveNext(out var token))
+        }
     }
 
     private static bool TryParseSet(ParserContext context)