In C#, as in many other languages, “_” is a valid identifier (as reminded to me by Erik Meijer on a C9 Lecture)
Recently, I used this knowledge to create the following extension method:
public static class StringExt {
public static XElement _(this string s,
params object[] objs) {
return new XElement(s, objs);
}
}
Why? To enable this coding style
"html"._(
"body"._(
"table"._(
"tr"._(
from colName in colNames
select "th"._(colName)),
from e in seq
select "tr"._(
from f in colFuncs
select "td"._( f(e))))))
.Save(name);
The above fragment creates an HTML document containing a table, where:
- IEnumerable<T> seq is a sequence of elements, where each element corresponds to a table row.
- List<string> colNames is a sequence of column names
- Linked<Func<T, string>> colFuncs is a sequence of functions, where each function is used to project one sequence element (e) into a column cell.
Without extension methods, this fragment would be written as:
new XElement("html",
new XElement("body",
new XElement("table",
new XElement("tr",
from colName in colNames
select new XElement("th", colName)),
from e in seq
select new XElement("tr",
from f in colFuncs
select new XElement("td", f(e))))))
.Save(name);
More “noisier”, on my opinion.
