help method
Implementation
String? help(String varName) {
if (symbols.containsKey(varName)) {
final decl = symbols[varName]!;
return decl.documentation;
} else if (importedSymbols.containsKey(varName)) {
final decl = importedSymbols[varName]!;
return decl.documentation;
} else if (closure != null) {
final decl =
closure!.memberGet(varName, isRecursive: true, throws: false);
if (decl != null) {
return (decl as HTDeclaration).documentation;
}
}
throw HTError.undefined(varName);
}