parseSelection method
Implementation
SelectionContext? parseSelection() {
var field = parseField();
if (field != null) return SelectionContext(field);
var fragmentSpread = parseFragmentSpread();
if (fragmentSpread != null) return SelectionContext(null, fragmentSpread);
var inlineFragment = parseInlineFragment();
if (inlineFragment != null) {
return SelectionContext(null, null, inlineFragment);
} else {
return null;
}
}