public static Expression <T> ComposeFromLambda <T>(LambdaExpression[] expressions, Func <Expression, Expression, Expression> merge)
{
if (expressions.Length == 0)
{
return(null);
}
var body = expressions[0].Body;
for (var i = 1; i < expressions.Length; i++)
{
var map = expressions[0].Parameters.Select((f, idx) => new { f, s = expressions[i].Parameters[idx] }).ToDictionary(p => p.s, p => (Expression)p.f);
var iBody = ParameterRebinder.ReplaceParameters(map, expressions[i].Body);
body = merge(body, iBody);
}
return(Expression.Lambda <T>(body, expressions[0].Parameters));
}
public static Expression <T> Compose <T>(this IEnumerable <Expression <T> > expressions, Func <Expression, Expression, Expression> merge)
{
var expressionsEnumerated = expressions.ToArray();
if (expressionsEnumerated.Length == 0)
{
return(null);
}
var body = expressionsEnumerated[0].Body;
for (var i = 1; i < expressionsEnumerated.Length; i++)
{
var map = expressionsEnumerated[0].Parameters.Select((f, idx) => new { f, s = expressionsEnumerated[i].Parameters[idx] }).ToDictionary(p => p.s, p => (Expression)p.f);
var iBody = ParameterRebinder.ReplaceParameters(map, expressionsEnumerated[i].Body);
body = merge(body, iBody);
}
return(Expression.Lambda <T>(body, expressionsEnumerated[0].Parameters));
}