add from giga-device, new branch added

StgSharp.Model/Step/Analyser/ExpSyntaxAnalyzer.Enum.cs

@@ -0,0 +1,68 @@
+//-----------------------------------------------------------------------
+//-----------------------------------------------------------------------
+//     file="ExpSyntaxAnalyzer.Enum.cs"
+//     Project: StgSharp
+//     AuthorGroup: Nitload Space
+//     Copyright (c) Nitload Space. All rights reserved.
+//     
+//     Permission is hereby granted, free of charge, to any person 
+//     obtaining a copy of this software and associated documentation 
+//     files (the “Software”), to deal in the Software without restriction, 
+//     including without limitation the rights to use, copy, modify, merge,
+//     publish, distribute, sublicense, and/or sell copies of the Software, 
+//     and to permit persons to whom the Software is furnished to do so, 
+//     subject to the following conditions:
+//     
+//     The above copyright notice and 
+//     this permission notice shall be included in all copies 
+//     or substantial portions of the Software.
+//     
+//     THE SOFTWARE IS PROVIDED “AS IS”, 
+//     WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
+//     INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
+//     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
+//     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
+//     DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
+//     ARISING FROM, OUT OF OR IN CONNECTION WITH 
+//     THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//     
+//-----------------------------------------------------------------------
+//-----------------------------------------------------------------------
+using StgSharp.Script;
+using StgSharp.Script.Express;
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace StgSharp.Model.Step
+{
+    internal partial class StepExpSyntaxAnalyzer
+    {
+
+        private static string ParseStepEnumLiteral( string source )
+        {
+            int length = source.Length;
+            ReadOnlySpan<char> span = source.AsSpan();
+            if( length > 2 && span[ 0 ] == '.' && span[ length - 1 ] == '.' ) {
+                return span.Slice( 1, length - 2 ).ToString();
+            }
+            throw new ExpInvalidSyntaxException( $"\"{source}\" is not a valid enum syntax" );
+        }
+
+        private void TryAppendEnum( Token e )
+        {
+            ExpSyntaxNode node = e.Value switch
+            {
+                ".T." => new ExpBoolNode( e, true, true ),
+                ".F." => new ExpBoolNode( e, false, true ),
+                ".U." => new ExpLogicValueNode( e, ExpLogic.Unknown, true ),
+                _ => ExpEnumLiteralNode.Create( e, ParseStepEnumLiteral ),
+            };
+            _cache.PushOperand( node );
+        }
+
+    }
+}