internal override int TryAddVariable(IEnumerable <Token> tokens, Token token, ICollection <Variable> variables, int i)
{
var branchVariable = new SwitchBranchVariable
{
Value = token.Flag
};
variables.Add(branchVariable);
var nextToken = tokens.ElementAt(i + 1);
if (nextToken.Flag != Strings.StartFlag1)
{
throw new ArgumentException(Tokens[0]);
}
var paramToken = tokens.ElementAt(i + 2);
var variable = new ConstVariable
{
Value = paramToken.Flag
};
branchVariable.Param = variable;
var nextCloseToken = tokens.ElementAt(i + 3);
if (nextCloseToken.Flag != Strings.EndFlag1)
{
throw new ArgumentException(Tokens[0]);
}
var n = tokens.Count();
ICollection <Token> subTokens = new List <Token>();
Util.CollectionTokens(tokens, subTokens, i + 4, Strings.StartFlag2, Strings.EndFlag2);
branchVariable.Variables = GetCaseVariables(subTokens);
return(i + 3 + subTokens.Count());
}
internal override int BuilderExpression(Context context)
{
SwitchBranchVariable switchBranch = (SwitchBranchVariable)context.Variable;
IEnumerable <CaseVariable> caseVariables = (IEnumerable <CaseVariable>)switchBranch.Variables;
var cases = caseVariables.Where(v => !v.Default && v.Variables != null && v.Variables.Any()).Select(
c => {
ICollection <Expression> expressions = new List <Expression>();
ExpressionBuilder.BuildExpression(expressions, c.Variables, context.ValuePairs, context.Datas);
var values = c.ConstVariable.Select(v => ExpressionBuilder.GetExpression(v, context.ValuePairs, context.Datas));
return(Expression.SwitchCase(Expression.Block(expressions), values));
}
).ToArray();
var defaultCase = caseVariables.FirstOrDefault(c => c.Default);
Expression defaultBody = null;
if (defaultCase != null)
{
ICollection <Expression> expressions = new List <Expression>();
ExpressionBuilder.BuildExpression(expressions, defaultCase.Variables, context.ValuePairs, context.Datas);
var values = defaultCase.ConstVariable.Select(v => ExpressionBuilder.GetExpression(v, context.ValuePairs, context.Datas));
defaultBody = Expression.Block(expressions);
}
else
{
var firstType = cases.First().Body.Type;
defaultBody = Expression.Block(firstType, Expression.Constant(Activator.CreateInstance(firstType)));
}
var param = ExpressionBuilder.GetExpression(switchBranch.Param, context.ValuePairs, context.Datas);
SwitchExpression switchExpression = Expression.Switch(param, defaultBody, cases);
context.Expressions.Add(switchExpression);
context.ExcuteParams.Clear();
return(context.Index);
}
