Parse command-line syntax

Parser/MParser.cs

@@ -347,6 +347,21 @@ namespace Parser
                         var operation = Factory.Token(EatToken());
                         expression = Factory.UnaryPostfixOperationExpression(expression, operation);
                         break;
+                    case TokenKind.UnquotedStringLiteral:
+                        if (expression is IdentifierNameNode idNameNode)
+                        {
+                            var arguments = new List<UnquotedStringLiteralNode>();
+                            while (CurrentToken.Kind == TokenKind.UnquotedStringLiteral)
+                            {
+                                arguments.Add(Factory.UnquotedStringLiteral(EatToken()));
+                            }
+
+                            return Factory.CommandExpression(idNameNode, arguments);
+                        }
+                        else
+                        {
+                            throw new ParsingException($"Unexpected token \"{CurrentToken.PureToken.LiteralText}\" during parsing expression \"{expression.FullText}\" at {CurrentToken.PureToken.Position}.");
+                        }
                     default:
                         return expression;
                 }

Parser/SyntaxFactory.cs

@@ -256,6 +256,12 @@ namespace Parser
             return new DoubleQuotedStringLiteralNode(stringLiteral);
         }
 
+        public UnquotedStringLiteralNode UnquotedStringLiteral(
+            Token stringLiteral)
+        {
+            return new UnquotedStringLiteralNode(stringLiteral);
+        }
+
         public ExpressionStatementNode ExpressionStatement(ExpressionNode expression)
         {
             var children = new List<SyntaxNode> {expression};
@@ -648,5 +654,22 @@ namespace Parser
             SetParent(result);
             return result;
         }
+
+        public CommandExpressionNode CommandExpression(
+            IdentifierNameNode identifierName,
+            List<UnquotedStringLiteralNode> arguments)
+        {
+            var children = new List<SyntaxNode>
+            {
+                identifierName
+            };
+            children.AddRange(arguments);
+            var result = new CommandExpressionNode(
+                children,
+                identifierName,
+                arguments);
+            SetParent(result);
+            return result;
+        }
     }
 }

Parser/SyntaxNode.cs

@@ -704,4 +704,20 @@ namespace Parser
             EndKeyword = endKeyword;
         }
     }
+
+    public class CommandExpressionNode : ExpressionNode
+    {
+        public IdentifierNameNode CommandName { get; }
+        public List<UnquotedStringLiteralNode> Arguments { get; }
+
+        public CommandExpressionNode(
+            List<SyntaxNode> children,
+            IdentifierNameNode commandName,
+            List<UnquotedStringLiteralNode> arguments
+        ) : base(children)
+        {
+            CommandName = commandName;
+            Arguments = arguments;
+        }
+    }
 }