class Psych::ScalarScanner - Documentation for Ruby 4.0
Description: class Psych::ScalarScanner: Scan scalars for built in types
Keywords: ruby,class,Psych::ScalarScanner

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# class Psych::ScalarScanner

Scan scalars for built in types

### Constants

FLOAT

  Taken from yaml.org/type/float.html Base 60, [-+]inf and NaN are handled separately

INTEGER_LEGACY

  Same as above, but allows commas. Not to YML spec, but kept for backwards compatibility

INTEGER_STRICT

  Taken from yaml.org/type/int.html and modified to ensure at least one numerical symbol exists

TIME

  Taken from yaml.org/type/timestamp.html

### Attributes

class_loader [R]

### Public Class Methods

new (class_loader, strict_integer: false, parse_symbols: true)
Source

    # File ext/psych/lib/psych/scalar_scanner.rb, line 30
    def initialize class_loader, strict_integer: false, parse_symbols: true
      @symbol_cache = {}
      @class_loader = class_loader
      @strict_integer = strict_integer
      @parse_symbols = parse_symbols
    end

Create a new scanner

### Public Instance Methods

parse_int (string)
Source

    # File ext/psych/lib/psych/scalar_scanner.rb, line 109
    def parse_int string
      Integer(string.delete(',_'))
    end

Parse and return an int from `string`

parse_time (string)
Source

    # File ext/psych/lib/psych/scalar_scanner.rb, line 115
    def parse_time string
      klass = class_loader.load 'Time'

      date, time = *(string.split(/[ tT]/, 2))
      (yy, m, dd) = date.match(/^(-?\d{4})-(\d{1,2})-(\d{1,2})/).captures.map { |x| x.to_i }
      md = time.match(/(\d+:\d+:\d+)(?:\.(\d*))?\s*(Z|[-+]\d+(:\d\d)?)?/)

      (hh, mm, ss) = md[1].split(':').map { |x| x.to_i }
      us = (md[2] ? Rational("0.#{md[2]}") : 0) * 1000000

      time = klass.utc(yy, m, dd, hh, mm, ss, us)

      return time if 'Z' == md[3]
      return klass.at(time.to_i, us) unless md[3]

      tz = md[3].match(/^([+\-]?\d{1,2})\:?(\d{1,2})?$/)[1..-1].compact.map { |digit| Integer(digit, 10) }
      offset = tz.first * 3600

      if offset < 0
        offset -= ((tz[1] || 0) * 60)
      else
        offset += ((tz[1] || 0) * 60)
      end

      klass.new(yy, m, dd, hh, mm, ss+us/(1_000_000r), offset)
    end

Parse and return a `Time` from `string`

tokenize (string)
Source

    # File ext/psych/lib/psych/scalar_scanner.rb, line 38
    def tokenize string
      return nil if string.empty?
      return @symbol_cache[string] if @symbol_cache.key?(string)
      integer_regex = @strict_integer ? INTEGER_STRICT : INTEGER_LEGACY
      # Check for a String type, being careful not to get caught by hash keys, hex values, and
      # special floats (e.g., -.inf).
      if string.match?(%r{^[^\d.:-]?[[:alpha:]_\s!@#$%\^&*(){}<>|/\\~;=]+}) || string.match?(/\n/)
        return string if string.length > 5

        if string.match?(/^[^ytonf~]/i)
          string
        elsif string == '~' || string.match?(/^null$/i)
          nil
        elsif string.match?(/^(yes|true|on)$/i)
          true
        elsif string.match?(/^(no|false|off)$/i)
          false
        else
          string
        end
      elsif string.match?(TIME)
        begin
          parse_time string
        rescue ArgumentError
          string
        end
      elsif string.match?(/^\d{4}-(?:1[012]|0\d|\d)-(?:[12]\d|3[01]|0\d|\d)$/)
        begin
          class_loader.date.strptime(string, '%F', Date::GREGORIAN)
        rescue ArgumentError
          string
        end
      elsif string.match?(/^\+?\.inf$/i)
        Float::INFINITY
      elsif string.match?(/^-\.inf$/i)
        -Float::INFINITY
      elsif string.match?(/^\.nan$/i)
        Float::NAN
      elsif @parse_symbols && string.match?(/^:./)
        if string =~ /^:(["'])(.*)\1/
          @symbol_cache[string] = class_loader.symbolize($2.sub(/^:/, ''))
        else
          @symbol_cache[string] = class_loader.symbolize(string.sub(/^:/, ''))
        end
      elsif string.match?(/^[-+]?[0-9][0-9_]*(:[0-5]?[0-9]){1,2}$/)
        i = 0
        string.split(':').each_with_index do |n,e|
          i += (n.to_i * 60 ** (e - 2).abs)
        end
        i
      elsif string.match?(/^[-+]?[0-9][0-9_]*(:[0-5]?[0-9]){1,2}\.[0-9_]*$/)
        i = 0
        string.split(':').each_with_index do |n,e|
          i += (n.to_f * 60 ** (e - 2).abs)
        end
        i
      elsif string.match?(FLOAT)
        if string.match?(/\A[-+]?\.\Z/)
          string
        else
          Float(string.delete(',_').gsub(/\.([Ee]|$)/, '\1'))
        end
      elsif string.match?(integer_regex)
        parse_int string
      else
        string
      end
    end

Tokenize `string` returning the Ruby object