Function printClassics

samples/Basic_Templates/app/application.cpp:50–90

* Demonstrate using callbacks instead of CsvTemplate class, * and performing record filtering outside of template. */

 * and performing record filtering outside of template.
 */
void printClassics(const FlashString& templateSource, Format::Formatter& formatter)
{
	// The CSV data source
	CSV::Reader csv(new FileStream(Filename::classics_csv));

	// Use a regular SectionTemplate class to process the template
	SectionTemplate tmpl(new FSTR::Stream(templateSource));

	// We're going to filter the data based on publication year
	String year_filter("1996");
	// Provide this to the template so it can show it in the header
	tmpl.setVar(_F("year_filter"), year_filter);
	// Improve speed by pre-fetching the filter column index
	unsigned yearColumn = csv.getColumn(_F("bibliography.publication.year"));

	// Set up callback to handle fetching/filtering records
	tmpl.onNextRecord([&]() -> bool {
		if(tmpl.sectionIndex() == 1) {
			while(csv.next()) {
				// Could also use a more generic (but slower) approach:
				//   if(year_filter == tmpl.getValue("bibliography.publication.year"))

				if(year_filter == csv.getValue(yearColumn)) {
					return true;
				}
			}
			return false;
		}
		return tmpl.recordIndex() < 0;
	});

	// Set up callback to fetch values from CSV record
	tmpl.onGetValue([&](const char* name) -> String {
		String s = csv.getValue(name);
		formatter.escape(s);
		return s;
	});

	// Dump result to terminal
	Serial.copyFrom(&tmpl);
}

} // namespace