/// <summary>
/// Attempts to parse a modification.
/// </summary>
static public bool TryParse(StringSlice inData, out VariantModification outModification)
{
inData = inData.Trim();
VariantModifyOperator op = default(VariantModifyOperator);
int operatorIdx = -1;
int operatorLength = 0;
VariantUtils.TryFindOperator(inData, '=', VariantModifyOperator.Set, ref operatorIdx, ref op, ref operatorLength);
VariantUtils.TryFindOperator(inData, '+', VariantModifyOperator.Add, ref operatorIdx, ref op, ref operatorLength);
VariantUtils.TryFindOperator(inData, '-', VariantModifyOperator.Subtract, ref operatorIdx, ref op, ref operatorLength);
VariantUtils.TryFindOperator(inData, '*', VariantModifyOperator.Multiply, ref operatorIdx, ref op, ref operatorLength);
VariantUtils.TryFindOperator(inData, '/', VariantModifyOperator.Divide, ref operatorIdx, ref op, ref operatorLength);
if (operatorIdx < 0)
{
outModification = default(VariantModification);
return(false);
}
outModification.Operator = op;
StringSlice key = inData.Substring(0, operatorIdx);
StringSlice operand = inData.Substring(operatorIdx + 1);
if (!TableKeyPair.TryParse(key, out outModification.VariableKey))
{
outModification = default(VariantModification);
return(false);
}
return(VariantOperand.TryParse(operand, out outModification.Operand));
}
/// <summary>
/// Attempts to apply one or more modifications, described by the given string.
/// </summary>
static public bool TryModify(this IVariantResolver inResolver, object inContext, StringSlice inModifyData, IMethodCache inInvoker = null)
{
if (inModifyData.IsWhitespace)
{
return(true);
}
StringSlice.ISplitter splitter = QuoteAwareSplitter ?? (QuoteAwareSplitter = new StringUtils.ArgsList.Splitter(false));
bool bSuccess = true;
VariantModification mod;
foreach (var group in inModifyData.EnumeratedSplit(splitter, StringSplitOptions.RemoveEmptyEntries))
{
if (!VariantModification.TryParse(group, out mod) || !mod.Execute(inResolver, inContext, inInvoker))
{
bSuccess = false;
}
}
return(bSuccess);
}
