parse method
Creates a Map. Duplicate keys are silently discarded.
Implementation
Map<String, String> parse(Iterable<String> lines) {
var out = <String, String>{};
for (var line in lines) {
var kv = parseOne(line, env: out);
if (kv.isEmpty) continue;
out.putIfAbsent(kv.keys.single, () => kv.values.single);
}
return out;
}