class Rack::QueryParser

def _normalize_params(params, name, v, depth)
ParamsTooDeepError if depth >= param_depth_limit
me
l name, treat same as empty string (required by tests)
after = ''
depth == 0
art of parsing, don't treat [] or [ at start of string specially
tart = name.index('[', 1)
Start of parameter nesting, use part before brackets as key
= name[0, start]
ter = name[start, name.length]

Plain parameter with no nesting
= name
ter = ''
name.start_with?('[]')
ray nesting
'[]'
r = name[2, name.length]
name.start_with?('[') && (start = name.index(']', 1))
sh nesting, use the part inside brackets as the key
name[1, start-1]
r = name[start+1, name.length]
obably malformed input, nested but not starting with [
eat full name as key for backwards compatibility.
name
r = ''
 if k.empty?
er == ''
 == '[]' && depth != 0
turn [v]

rams[k] = v
after == "["
ms[name] = v
after == "[]"
ms[k] ||= []
e ParameterTypeError, "expected Array (got #{params[k].class.name}) for param `#{k}'" unless params[k].is_a?(Array)
ms[k] << v
after.start_with?('[]')
cognize x[][y] (hash inside array) parameters
ss after[2] == '[' && after.end_with?(']') && (child_key = after[3, after.length-4]) && !child_key.empty? && !child_key.index('[') && !child_key.index(']')
Handle other nested array parameters
ild_key = after[2, after.length]
ms[k] ||= []
e ParameterTypeError, "expected Array (got #{params[k].class.name}) for param `#{k}'" unless params[k].is_a?(Array)
arams_hash_type?(params[k].last) && !params_hash_has_key?(params[k].last, child_key)
ormalize_params(params[k].last, child_key, v, depth + 1)

rams[k] << _normalize_params(make_params, child_key, v, depth + 1)
ms[k] ||= make_params
e ParameterTypeError, "expected Hash (got #{params[k].class.name}) for param `#{k}'" unless params_hash_type?(params[k])
ms[k] = _normalize_params(params[k], after, v, depth + 1)