/// <summary>Gets a new list with any #trivia_trailing attributes removed. Those trivia are returned in an `out` parameter.</summary>
public static VList <LNode> WithoutTrailingTrivia(this VList <LNode> attrs, out VList <LNode> trailingTrivia)
{
var trailingTrivia2 = VList <LNode> .Empty;
attrs = attrs.Transform((int i, ref LNode attr) => {
if (attr.Calls(S.TriviaTrailing))
{
trailingTrivia2.AddRange(attr.Args);
return(XfAction.Drop);
}
return(XfAction.Keep);
});
trailingTrivia = trailingTrivia2; // cannot use `out` parameter within lambda method
return(attrs);
}
public void TestExampleTransforms()
{
// These examples are listed in the documentation of FVList.Transform().
// There are more Transform() tests in VListTests() and RWListTests().
VList<int> list = new VList<int>(new int[] { -1, 2, -2, 13, 5, 8, 9 });
VList<int> output;
output = list.Transform((int i, ref int n) =>
{ // Keep every second item
return (i % 2) == 1 ? XfAction.Keep : XfAction.Drop;
});
ExpectList(output, 2, 13, 8);
output = list.Transform((int i, ref int n) =>
{ // Keep odd numbers
return (n % 2) != 0 ? XfAction.Keep : XfAction.Drop;
});
ExpectList(output, -1, 13, 5, 9);
output = list.Transform((int i, ref int n) =>
{ // Keep and square all odd numbers
if ((n % 2) != 0) {
n *= n;
return XfAction.Change;
} else
return XfAction.Drop;
});
ExpectList(output, 1, 169, 25, 81);
output = list.Transform((int i, ref int n) =>
{ // Increase each item by its index
n += i;
return i == 0 ? XfAction.Keep : XfAction.Change;
});
ExpectList(output, -1, 3, 0, 16, 9, 13, 15);
list = new VList<int>(new int[] { 1, 2, 3 });
output = list.Transform(delegate(int i, ref int n) {
return i >= 0 ? XfAction.Repeat : XfAction.Keep;
});
ExpectList(output, 1, 1, 2, 2, 3, 3);
output = list.Transform(delegate(int i, ref int n) {
if (i >= 0)
return XfAction.Repeat;
n *= 10;
return XfAction.Change;
});
ExpectList(output, 1, 10, 2, 20, 3, 30);
output = list.Transform(delegate (int i, ref int n) {
if (i >= 0) {
n *= 10;
return XfAction.Repeat;
}
return XfAction.Keep;
});
ExpectList(output, 10, 1, 20, 2, 30, 3);
output = list.Transform(delegate (int i, ref int n) {
n *= 10;
if (n > 1000)
return XfAction.Drop;
return XfAction.Repeat;
});
ExpectList(output, 10, 100, 1000, 20, 200, 30, 300);
}
/// <summary>Gets a new list with any #trivia_trailing attributes removed.</summary>
public static VList <LNode> WithoutTrailingTrivia(this VList <LNode> attrs)
{
return(attrs.Transform((int i, ref LNode attr) => attr.Calls(S.TriviaTrailing) ? XfAction.Drop : XfAction.Keep));
}
