/// <summary>
/// Creates a new ScriptVersion with the given parameters.
/// </summary>
/// <param name="spec">The specification to use, or 0 (zero) to use ECMA standard.</param>
/// <param name="specVersion">The specification version. Pass 0 if using ECMA standard.</param>
/// <param name="ecmaVersion"></param>
/// <param name="allowDeprecated"></param>
/// <param name="allowProposals"></param>
/// <returns></returns>
public static ScriptVersion Create(ScriptVersion spec, int specVersion, int ecmaVersion, bool allowDeprecated, bool allowProposals)
{
if (spec.GetSpecification() != spec)
{
throw new ArgumentException("Pure specification expected in parameter.", nameof(spec));
}
if (spec == 0 && specVersion != 0)
{
throw new ArgumentException("Specification version must be zero when no specification is passed.", nameof(specVersion));
}
var specVerFld = specVersion * Consts.SVerFld;
if (specVerFld >= Consts.SVerLim)
{
throw new ArgumentException("Specification version overflow.", nameof(specVersion));
}
var ecmaVerFld = ecmaVersion * Consts.EcmaFld;
if (ecmaVerFld >= Consts.EcmaLim)
{
throw new ArgumentException("ECMAScript version overflow.", nameof(ecmaVersion));
}
var flags = (allowProposals ? 1 : 0) + (allowDeprecated ? 2 : 0);
return(spec + specVerFld + ecmaVerFld + flags * Consts.FlagFld);
}
/// <summary>
/// Changes the script version to accept proposed features.
/// </summary>
/// <param name="scriptVersion"></param>
/// <returns></returns>
public static ScriptVersion Proposals(this ScriptVersion scriptVersion, bool value)
{
return(Create(
scriptVersion.GetSpecification(),
scriptVersion.GetSpecificationVersion(),
scriptVersion.GetStandardVersion(),
scriptVersion.IsDeprecated(),
value));
}
/// <summary>
/// Changes the script version to accept deprecated features.
/// </summary>
/// <param name="scriptVersion"></param>
/// <returns></returns>
public static ScriptVersion Deprecated(this ScriptVersion scriptVersion)
{
return(Create(
scriptVersion.GetSpecification(),
scriptVersion.GetSpecificationVersion(),
scriptVersion.GetStandardVersion(),
true,
scriptVersion.IsProposals()));
}
/// <summary>
/// Changes the script version to accept Javascript (Mozilla) features.
/// </summary>
/// <param name="scriptVersion"></param>
/// <returns></returns>
public static ScriptVersion Javascript(this ScriptVersion scriptVersion, int specVersion)
{
if (scriptVersion.GetSpecification() != 0)
{
throw new ArgumentException("Script version must have no assigned specification.", nameof(scriptVersion));
}
return(Create(
ScriptVersion.Js,
specVersion,
scriptVersion.GetStandardVersion(),
scriptVersion.IsDeprecated(),
scriptVersion.IsProposals()));
}
/// <summary>
/// Whether a specific version of the script is a superset of another version.
/// This can be used as a rather general feature indicator, but there may be exceptions, such as deprecated features.
/// </summary>
/// <param name="scriptVersion"></param>
/// <param name="baseScriptVersion"></param>
/// <returns></returns>
public static bool IsSupersetOf(this ScriptVersion scriptVersion, ScriptVersion baseScriptVersion)
{
var specOther = baseScriptVersion.GetSpecification();
if (specOther == 0)
{
return(scriptVersion.GetStandardVersion() >= baseScriptVersion.GetStandardVersion());
}
var specThis = scriptVersion.GetSpecification();
if (specThis == ScriptVersion.NonStandard)
{
return(scriptVersion.GetStandardVersion() >= baseScriptVersion.GetStandardVersion());
}
if (specThis == specOther)
{
return(scriptVersion.GetSpecificationVersion() >= baseScriptVersion.GetSpecificationVersion());
}
return(false);
}