Class: JSON::Pure::Parser

Inherits:
StringScanner
  • Object
show all
Defined in:
lib/json/pure/parser.rb

Overview

This class implements the JSON parser that is used to parse a JSON string into a Ruby data structure.

Constant Summary collapse

STRING = 
/" ((?:[^\x0-\x1f"\\] |
     # escaped special characters:
    \\["\\\/bfnrt] |
    \\u[0-9a-fA-F]{4} |
     # match all but escaped special characters:
    \\[\x20-\x21\x23-\x2e\x30-\x5b\x5d-\x61\x63-\x65\x67-\x6d\x6f-\x71\x73\x75-\xff])*)
"/nx
INTEGER = 
/(-?0|-?[1-9]\d*)/
FLOAT = 
/(-?
(?:0|[1-9]\d*)
(?:
  \.\d+(?i:e[+-]?\d+) |
  \.\d+ |
  (?i:e[+-]?\d+)
)
)/x
NAN = 
/NaN/
INFINITY = 
/Infinity/
MINUS_INFINITY = 
/-Infinity/
OBJECT_OPEN = 
/\{/
OBJECT_CLOSE = 
/\}/
ARRAY_OPEN = 
/\[/
ARRAY_CLOSE = 
/\]/
PAIR_DELIMITER = 
/:/
COLLECTION_DELIMITER = 
/,/
TRUE = 
/true/
FALSE = 
/false/
NULL = 
/null/
IGNORE = 
%r(
  (?:
   //[^\n\r]*[\n\r]| # line comments
   /\*               # c-style comments
   (?:
    [^*/]|        # normal chars
    /[^*]|        # slashes that do not start a nested comment
    \*[^/]|       # asterisks that do not end this comment
    /(?=\*/)      # single slash before this comment's end
   )*
     \*/               # the End of this comment
     |[ \t\r\n]+       # whitespaces: space, horizontal tab, lf, cr
  )+
)mx
UNPARSED = 
Object.new.freeze

Instance Method Summary collapse

Constructor Details

#initialize(source, opts = {}) ⇒ Parser

Creates a new JSON::Pure::Parser instance for the string source.

It will be configured by the opts hash. opts can have the following keys:

  • max_nesting: The maximum depth of nesting allowed in the parsed data structures. Disable depth checking with :max_nesting => false|nil|0, it defaults to 100.

  • allow_nan: If set to true, allow NaN, Infinity and -Infinity in defiance of RFC 7159 to be parsed by the Parser. This option defaults to false.

  • freeze: If set to true, all parsed objects will be frozen. Parsed string will be deduplicated if possible.

  • symbolize_names: If set to true, returns symbols for the names (keys) in a JSON object. Otherwise strings are returned, which is also the default. It’s not possible to use this option in conjunction with the create_additions option.

  • create_additions: If set to true, the Parser creates additions when a matching class and create_id are found. This option defaults to false.

  • object_class: Defaults to Hash

  • array_class: Defaults to Array

  • decimal_class: Specifies which class to use instead of the default

    (Float) when parsing decimal numbers. This class must accept a single
string argument in its constructor.



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# File 'lib/json/pure/parser.rb', line 78

def initialize(source, opts = {})
  opts ||= {}
  source = convert_encoding source
  super source
  if !opts.key?(:max_nesting) # defaults to 100
    @max_nesting = 100
  elsif opts[:max_nesting]
    @max_nesting = opts[:max_nesting]
  else
    @max_nesting = 0
  end
  @allow_nan = !!opts[:allow_nan]
  @symbolize_names = !!opts[:symbolize_names]
  @freeze = !!opts[:freeze]
  if opts.key?(:create_additions)
    @create_additions = !!opts[:create_additions]
  else
    @create_additions = false
  end
  @symbolize_names && @create_additions and raise ArgumentError,
    'options :symbolize_names and :create_additions cannot be used '\
    'in conjunction'
  @create_id = @create_additions ? JSON.create_id : nil
  @object_class = opts[:object_class] || Hash
  @array_class  = opts[:array_class] || Array
  @decimal_class = opts[:decimal_class]
  @match_string = opts[:match_string]
end

Instance Method Details

#parse ⇒ Object

Parses the current JSON string source and returns the complete data structure as a result.



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# File 'lib/json/pure/parser.rb', line 116

def parse
  reset
  obj = nil
  while !eos? && skip(IGNORE) do end
  if eos?
    raise ParserError, "source is not valid JSON!"
  else
    obj = parse_value
    UNPARSED.equal?(obj) and raise ParserError,
      "source is not valid JSON!"
    obj.freeze if @freeze
  end
  while !eos? && skip(IGNORE) do end
  eos? or raise ParserError, "source is not valid JSON!"
  obj
end

#reset ⇒ Object 



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# File 'lib/json/pure/parser.rb', line 109

def reset
  super
  @current_nesting = 0
end