/// <summary>
/// Ctor
/// </summary>
/// <remarks></remarks>
public EcmaScriptIdentifier(string ident)
{
this.identifier =
String.IsNullOrEmpty(ident) ?
String.Empty :
EcmaScriptIdentifier.VerifyIdentifier(ident, true);
}
protected override void WritePropertyName(TextWriter writer, string propertyName)
{
if (EcmaScriptIdentifier.IsValidIdentifier(propertyName, false))
{
// write out without quoting
writer.Write(propertyName);
}
else
{
// write out as an escaped string
base.WritePropertyName(writer, propertyName);
}
}
/// <summary>
/// Verifies is a valid EcmaScript variable expression
/// </summary>
/// <param name="ident">the identifier</param>
/// <returns>identifier</returns>
/// <remarks>
/// http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-262.pdf
///
/// IdentifierName =
/// IdentifierStart | IdentifierName IdentifierPart
/// IdentifierStart =
/// Letter | '$' | '_'
/// IdentifierPart =
/// IdentifierStart | Digit
/// </remarks>
public static bool IsValidIdentifier(string ident, bool nested)
{
if (String.IsNullOrEmpty(ident))
{
return(false);
}
if (nested)
{
string[] parts = ident.Split('.');
foreach (string part in parts)
{
if (!EcmaScriptIdentifier.IsValidIdentifier(part, false))
{
return(false);
}
}
return(true);
}
if (EcmaScriptIdentifier.IsReservedWord(ident))
{
return(false);
}
bool indentPart = false;
for (int i = 0, length = ident.Length; i < length; i++)
{
char ch = ident[i];
if (indentPart && ((ch >= '0') && (ch <= '9')))
{
// digits are only allowed after first char
continue;
}
// can be start or part
if (((ch >= 'a') && (ch <= 'z')) ||
((ch >= 'A') && (ch <= 'Z')) ||
(ch == '_') || (ch == '$'))
{
indentPart = true;
continue;
}
return(false);
}
return(true);
}
/// <summary>
/// Compares identifiers
/// </summary>
/// <param name="obj"></param>
/// <returns></returns>
public override bool Equals(object obj)
{
EcmaScriptIdentifier that = obj as EcmaScriptIdentifier;
if (that == null)
{
return(base.Equals(obj));
}
if (String.IsNullOrEmpty(this.identifier) && String.IsNullOrEmpty(that.identifier))
{
// null and String.Empty are equivalent
return(true);
}
return(StringComparer.Ordinal.Equals(this.identifier, that.identifier));
}
/// <summary>
/// Verifies is a valid EcmaScript identifier
/// </summary>
/// <param name="ident">the identifier</param>
/// <returns>identifier</returns>
public static string VerifyIdentifier(string ident, bool nested, bool throwOnEmpty)
{
if (String.IsNullOrEmpty(ident))
{
if (throwOnEmpty)
{
throw new ArgumentException("Identifier is empty.");
}
return(String.Empty);
}
ident = ident.Replace(" ", "");
if (!EcmaScriptIdentifier.IsValidIdentifier(ident, nested))
{
throw new ArgumentException("Identifier \"" + ident + "\" is not supported.");
}
return(ident);
}
/// <summary>
/// Verifies is a valid EcmaScript identifier
/// </summary>
/// <param name="ident">the identifier</param>
/// <returns>identifier</returns>
public static string VerifyIdentifier(string ident, bool nested)
{
return(EcmaScriptIdentifier.VerifyIdentifier(ident, nested, true));
}