System.Xml.Xsl.XsltOld.PrefixQName.ValidatePrefix C# (CSharp) Method

        public static bool ValidatePrefix(string prefix) {
            if (prefix.Length == 0) {
                return false;
            }
            XmlCharType xmlCharType = XmlCharType.Instance;
            if (! xmlCharType.IsStartNCNameChar(prefix[0])) {
                return false;
            }
            for (int i = 1; i < prefix.Length; i ++) {
                if (! xmlCharType.IsNCNameChar(prefix[i])) {
                    return false;
                }
            }
            return true;
        }
    }

        private void AddScript(Compiler compiler)
        {
            NavigatorInput input = compiler.Input;

            ScriptingLanguage lang = ScriptingLanguage.JScript;
            string            implementsNamespace = null;

            if (input.MoveToFirstAttribute())
            {
                do
                {
                    if (input.LocalName == input.Atoms.Language)
                    {
                        string langName = input.Value;
                        if (
                            String.Compare(langName, "jscript", StringComparison.OrdinalIgnoreCase) == 0 ||
                            String.Compare(langName, "javascript", StringComparison.OrdinalIgnoreCase) == 0
                            )
                        {
                            lang = ScriptingLanguage.JScript;
                        }
                        else if (
                            String.Compare(langName, "c#", StringComparison.OrdinalIgnoreCase) == 0 ||
                            String.Compare(langName, "csharp", StringComparison.OrdinalIgnoreCase) == 0
                            )
                        {
                            lang = ScriptingLanguage.CSharp;
                        }
                        else
                        {
                            throw XsltException.Create(Res.Xslt_ScriptInvalidLanguage, langName);
                        }
                    }
                    else if (input.LocalName == input.Atoms.ImplementsPrefix)
                    {
                        if (!PrefixQName.ValidatePrefix(input.Value))
                        {
                            throw XsltException.Create(Res.Xslt_InvalidAttrValue, input.LocalName, input.Value);
                        }
                        implementsNamespace = compiler.ResolveXmlNamespace(input.Value);
                    }
                }while (input.MoveToNextAttribute());
                input.ToParent();
            }
            if (implementsNamespace == null)
            {
                throw XsltException.Create(Res.Xslt_MissingAttribute, input.Atoms.ImplementsPrefix);
            }
            if (!input.Recurse() || input.NodeType != XPathNodeType.Text)
            {
                throw XsltException.Create(Res.Xslt_ScriptEmpty);
            }
            compiler.AddScript(input.Value, lang, implementsNamespace, input.BaseURI, input.LineNumber);
            input.ToParent();
        }