begin method
Called when the beginning of a tag is encountered.
Implementation
@override
void begin(TagContext tc, String data) {
final attrs = parseArgs(data);
if (!attrs.isEmpty) {
tc.write("\n${tc.pre}response.headers");
bool first = true;
for (final nm in attrs.keys) {
final val = attrs[nm];
if (val == null)
tc.error("The $nm attribute requires a value.");
if (first) first = false;
else tc.write("\n${tc.pre} ");
tc.write('..add("$nm", ${toEL(val)})');
}
tc.writeln(';${tc.getLineNumberComment()}');
}
}