mruby-numeric-ext

Purpose

This mrbgem extends the Numeric and Integer classes in mruby with additional methods for common numerical operations and checks.

Functionality

This gem adds the following methods:

Numeric Class

zero?: Returns true if the number is zero, false otherwise.
nonzero?: Returns the number itself if it's not zero, nil otherwise.
positive?: Returns true if the number is greater than 0, false otherwise.
negative?: Returns true if the number is less than 0, false otherwise.
integer?: Returns true if the number is an Integer (this is overridden in the Integer class).

Integer Class

allbits?(mask): Returns true if all bits of self & mask are 1.
anybits?(mask): Returns true if any bits of self & mask are 1.
nobits?(mask): Returns true if no bits of self & mask are 1.
bit_length: Returns the number of bits of the absolute value of self in binary. 0.bit_length #=> 0; (-1).bit_length #=> 0; 2.bit_length #=> 2.
ceildiv(other): Returns the result of self divided by other, rounded up to the nearest integer.
integer?: Returns true (overrides Numeric#integer?).
remainder(numeric): Returns the remainder of self divided by numeric. Equivalent to x - y * (x / y).truncate.
pow(numeric): Returns self raised to the power of numeric.
pow(integer, integer): Returns modular exponentiation ((self ** exponent) % modulus).
digits(base=10): Returns an array of integers representing the base-radix digits of self. The first element is the least significant digit.
size: Returns the number of bytes in the machine representation of the integer.
odd?: Returns true if the integer is odd, false otherwise.
even?: Returns true if the integer is even, false otherwise.
Integer.sqrt(integer): (Class method) Returns the integer square root of the given non-negative integer.

How to use

To use this mrbgem, add it to your build_config.rb:

MRuby::Build.new do |conf|
  # ... (other configurations)
  conf.gem :core => 'mruby-numeric-ext'
end

Then you can use the extended methods:

p 5.positive?  # => true
p (-3).negative? # => true
p 0.zero?      # => true
p 5.nonzero?   # => 5
p 0.nonzero?   # => nil

p 7.allbits?(3)  # => false (binary 111 & 011 is 011, not 011)
p 7.anybits?(3)  # => true
p 7.nobits?(8)   # => true (binary 111 & 1000 is 000)

p 10.ceildiv(3)   # => 4
p (-10).ceildiv(3) # => -3

p 10.remainder(3) # => 1
p (-10).remainder(3) # => -1

p 2.pow(3)        # => 8
p 2.pow(3, 5)     # => 3 ( (2**3) % 5 )

p 12345.digits    # => [5, 4, 3, 2, 1]
p 12345.digits(16) # => [9, 3, 0, 3]

p 42.size         # => (depends on machine, e.g., 4 or 8)
p 5.bit_length    # => 3
p 5.odd?          # => true
p 4.even?         # => true
p Integer.sqrt(16) # => 4
p Integer.sqrt(17) # => 4

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