Update FormulaParser.cs

Add support for array formulae in arguments.
Ex: =SomeFunction({1,2}, {3,

Author: Ron-Ldn

Source/ExcelDna.IntelliSense/UIMonitor/FormulaParser.cs

@@ -17,19 +17,32 @@ static class FormulaParser
         internal static bool TryGetFormulaInfo(string formulaPrefix, out string functionName, out int currentArgIndex)
         {
             Debug.Assert(formulaPrefix != null);
-            
+
+            // Hide the strings, in order to ignore the commas, parenthesis and curly brackets which might be inside.
+            // Ex: =SomeFunction("a", "b,c(d,{e,f, 
+            // In the example above, the function is SomeFunction, and the index is 2
+
+            // If editing a string, then close the double-quotes
             if (formulaPrefix.Count(c => c == '\"') % 2 != 0)
             {
                 formulaPrefix = string.Concat(formulaPrefix, '\"');
             }
 
-            formulaPrefix = Regex.Replace(formulaPrefix, "(\"[^\"]*\")|(\\([^\\(\\)]*\\))| ", string.Empty);
+            // Remove the strings.
+            // Note: in Excel, in order to put a double-quotes in a string, one has to double the double-quotes.
+            // For instance, "a""b" for a"b. Since we only want to hide the strings in order to count the commas, 
+            // the regex below still applies.
+            formulaPrefix = Regex.Replace(formulaPrefix, "(\"[^\"]*\")", string.Empty);
+
+            // Remove sub-formulae
+            formulaPrefix = Regex.Replace(formulaPrefix, "(\\([^\\(\\)]*\\))| ", string.Empty);
 
             while (Regex.IsMatch(formulaPrefix, "\\([^\\(\\)]*\\)"))
             {
                 formulaPrefix = Regex.Replace(formulaPrefix, "\\([^\\(\\)]*\\)", string.Empty);
             }
 
+            // Find the function name and the argument index
             int lastOpeningParenthesis = formulaPrefix.LastIndexOf("(", formulaPrefix.Length - 1, StringComparison.Ordinal);
 
             if (lastOpeningParenthesis > -1)
@@ -38,7 +51,24 @@ internal static bool TryGetFormulaInfo(string formulaPrefix, out string function
                 if (match.Success)
                 {
                     functionName = match.Groups[functionNameGroupName].Value;
-                    currentArgIndex = formulaPrefix.Substring(lastOpeningParenthesis, formulaPrefix.Length - lastOpeningParenthesis).Count(c => c == ListSeparator);
+
+                    string argumentsPart = formulaPrefix.Substring(lastOpeningParenthesis, formulaPrefix.Length - lastOpeningParenthesis);
+
+                    // Hide array formulae
+                    // Ex: =SomeFunction("a", {"a", "b", "c"
+                    // In the example above the index is 2
+
+                    // If editing an array, then close the curly bracket.
+                    // Since we already removed the strings, there won't be any curly brackets within a string.
+                    if (argumentsPart.Count(c => c == '{') > argumentsPart.Count(c => c == '}'))
+                    {
+                        argumentsPart = string.Concat(argumentsPart, '}');
+                    }
+
+                    // Remove the arrays.
+                    argumentsPart = Regex.Replace(argumentsPart, "(\\{[^\\}]*\\})", string.Empty);
+
+                    currentArgIndex = argumentsPart.Count(c => c == ListSeparator);
                     return true;
                 }
             }