in facebook-clang-plugins/libtooling/atdlib/ATDWriter.h [321:337]
void tab() {
if (previousElementIsVariantTag_) {
if (options_.prettifyJson) {
os_ << (options_.useYojson ? COLONWITHSPACES : COMMAWITHSPACES);
} else {
os_ << (options_.useYojson ? COLON : COMMA);
}
} else if (previousElementNeedsComma_) {
os_ << COMMA;
}
if (nextElementNeedsNewLine_ && options_.prettifyJson) {
os_ << NEWLINE;
for (size_t i = 0; i < indentLevel_; i++) {
os_ << TAB;
}
}
}