public void AddIfMissing(
string displayText,
string suffix,
string description,
RegexNode parentOpt,
int?positionOffset = null,
string insertionText = null
)
{
var replacementStart = parentOpt != null?parentOpt.GetSpan().Start : Position;
var replacementSpan = TextSpan.FromBounds(replacementStart, Position);
var newPosition = replacementStart + positionOffset;
insertionText ??= displayText;
var escapedInsertionText = _language.EscapeText(insertionText, StringToken);
if (escapedInsertionText != insertionText)
{
newPosition += escapedInsertionText.Length - insertionText.Length;
}
AddIfMissing(
new RegexItem(
displayText,
suffix,
description,
CompletionChange.Create(
new TextChange(replacementSpan, escapedInsertionText),
newPosition
)
)
);
}