==================
basic block
block_1 {
}
---
(config_file
(body
(block
(identifier))))
basic block on one line
block_1 {}
block with attribute
block_1 "strlit1" "strlit2" {
attr1 = "val1"
(identifier)
(string_lit)
(attribute
(expression
(expr_term
(literal_value
(string_lit)))))))))
nested block
block_2 {
(identifier))))))
nested block on one line
block_2 {}
nested blocks
block_3 {}
(identifier))
