Merge pull request #167 from SpiceSharp/alpha_&_omega

Add support for Alpha_&_Omega const (LTSpice support)

Author: marcin-golebiowski

src/SpiceSharpParser/Lexers/Expressions/Lexer.cs

@@ -198,14 +198,15 @@ public void Next()
                         number >= 'A' && number <= 'Z'))
                         Continue();
                     break;
-                case char letter when letter >= 'a' && letter <= 'z' || letter >= 'A' && letter <= 'Z' || letter == '_':
+                case char letter when letter >= 'a' && letter <= 'z' || letter >= 'A' && letter <= 'Z':
                     Type = TokenType.Identifier;
                     Continue();
                     while ((Index < _expression.Length) && ((
                         letter = _expression[Index]) >= 'a' && letter <= 'z' ||
                         letter >= 'A' && letter <= 'Z' ||
                         letter >= '0' && letter <= '9' ||
-                        letter == '_'))
+                        letter == '_' ||
+                        letter == '&'))
                         Continue();
                     break;
 

src/SpiceSharpParser/Lexers/Netlist/Spice/SpiceLexer.cs

@@ -60,7 +60,7 @@ private void BuildGrammar()
         {
             var builder = new LexerGrammarBuilder<SpiceLexerState>();
             builder.AddRegexRule(new LexerInternalRule("LETTER", "[a-zA-Zµ]"));
-            builder.AddRegexRule(new LexerInternalRule("CHARACTER", @"[a-zA-Z0-9\-\+§µ]"));
+            builder.AddRegexRule(new LexerInternalRule("CHARACTER", @"[a-zA-Z0-9\-\+§µ_&]"));
             builder.AddRegexRule(new LexerInternalRule("DIGIT", "[0-9]"));
             builder.AddRegexRule(new LexerInternalRule("SPECIAL", @"[\/\\_\.:%!\#\-;\<\>\^\*\[\]]"));
             builder.AddRegexRule(new LexerTokenRule<SpiceLexerState>(

src/SpiceSharpParser/ModelReaders/Netlist/Spice/Evaluation/SpiceEvaluationContext.cs

@@ -79,6 +79,7 @@ private void CreateSpiceParameters()
             Parameters.Add("c", new ConstantExpression(299792500));
             Parameters.Add("boltz", new ConstantExpression(1.38062e-23));
             Parameters.Add("NaN", new ConstantExpression(double.NaN));
+            Parameters.Add("Alpha_&_Omega", new ConstantExpression(double.PositiveInfinity));
         }
     }
 }