mruby-kernel-ext

This mrbgem extends the Kernel module in mruby with additional useful methods.

Methods

fail(*args)

Raises a RuntimeError. This is an alias for raise.

Example:

fail "Something went wrong"
# Raises RuntimeError: Something went wrong

caller(start=1, length=nil) -> array | nil

caller(range) -> array | nil

Returns the current execution stack (backtrace).

• If start is provided, it indicates the number of frames to skip.
• If length is provided, it limits the number of frames returned.
• If a range is provided, it specifies the portion of the stack to return.

Returns nil if start is greater than or equal to the number of frames in the stack.

Example:

def foo
  bar
end

def bar
  puts caller(0) # Show all frames starting from the current one
  puts caller(1) # Skip one frame
end

foo

__method__ -> symbol | nil

Returns the name of the current method as a Symbol. If called outside of a method, it returns nil.

Example:

class MyClass
  def my_method
    puts __method__
  end
end

MyClass.new.my_method
# Output: :my_method

__callee__ -> symbol | nil

Returns the called name of the current method as a Symbol. If called outside of a method, it returns nil. This can be different from __method__ when using aliases.

Example:

class MyClass
  def original_method
    puts __callee__
  end

  alias aliased_method original_method
end

obj = MyClass.new
obj.original_method # Output: :original_method
obj.aliased_method  # Output: :aliased_method

Integer(arg, base=0) -> integer

Converts arg to an Integer.

• Numeric types are converted directly (floating-point numbers are truncated).
• If arg is a String, base (0, or between 2 and 36) is used as the base for conversion.
  • If base is omitted or zero, radix indicators (0, 0b, 0x) in the string are honored.
• Strings must strictly conform to numeric representation, unlike String#to_i.
• Passing nil raises a TypeError.

Examples:

Integer(123.999)    #=> 123
Integer("0x1a")     #=> 26
Integer("0930", 10) #=> 930
Integer("111", 2)   #=> 7
# Integer(nil)        #=> TypeError
# Integer("invalid")  #=> ArgumentError

Float(arg) -> float

Converts arg to a Float.

• Numeric types are converted directly.
• Other types are converted using arg.to_f.
• Passing nil raises a TypeError.

Examples:

Float(1)           #=> 1.0
Float(123.456)     #=> 123.456
Float("123.456")   #=> 123.456
# Float(nil)         #=> TypeError
# Float("invalid")   #=> ArgumentError

String(arg) -> string

Converts arg to a String using its to_s method.

Examples:

String(self)        #=> "main"
String(self.class)  #=> "Object"
String(123456)      #=> "123456"
String(:symbol)     #=> "symbol"

Array(arg) -> array

Converts arg to an Array.

• If arg responds to to_a, it calls to_a to convert.
• Otherwise, it returns a new array containing arg as its single element.

Examples:

Array(1..5)          #=> [1, 2, 3, 4, 5]
Array([1, 2, 3])     #=> [1, 2, 3]
Array("hello")       #=> ["hello"] # If String does not have to_a
Array({ a: 1, b: 2 }) #=> [[:a, 1], [:b, 2]] # If Hash has to_a

Hash(arg) -> hash

Converts arg to a Hash.

• If arg is already a Hash, it is returned.
• If arg is nil or an empty Array, an empty Hash is returned.
• Otherwise, it raises a TypeError.

Examples:

Hash({ key: :value }) #=> { key: :value }
Hash(nil)             #=> {}
Hash([])              #=> {}
# Hash([1, 2, 3])       #=> TypeError