Module: Kernel

Defined in:
lib/garcon/core_ext/kernel.rb

Overview

Author: Stefano Harding <[email protected]> License: Apache License, Version 2.0 Copyright: © 2014-2015 Stefano Harding

Licensed under the Apache License, Version 2.0 (the “License”); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Instance Method Summary collapse

Instance Method Details

#callstack(level = 1) ⇒ Object Also known as: call_stack

Parse a caller string and break it into its components, returning an array composed of:

  • file (String)

  • lineno (Integer)

  • method (Symbol)

For example, from irb

callstack(1)

produces …

[["(irb)", 2, :irb_binding],
  ["/usr/lib/ruby/1.8/irb/workspace.rb", 52, :irb_binding],
  ["/usr/lib/ruby/1.8/irb/workspace.rb", 52, nil]]

Note: If the user decides to redefine caller() to output data in a different format, prior to requiring this, then the results will be indeterminate.



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# File 'lib/garcon/core_ext/kernel.rb', line 142

def callstack(level = 1)
  call_str_array = pp_callstack(level)
  stack = []
  call_str_array.each{ |call_str|
    file, lineno, method = call_str.split(':')
    if method =~ /in `(.*)'/ then
      method = $1.intern()
    end
    stack << [file, lineno.to_i, method]
  }
  stack
end

#maybe(chance = 0.5, &block) ⇒ Object

Random generator that returns true or false. Can also take a block that has a 50/50 chance to being executed.



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# File 'lib/garcon/core_ext/kernel.rb', line 24

def maybe(chance = 0.5, &block)
  if block
    yield if rand < chance
  else
    rand < chance
  end
end

#not_nil? ⇒ Boolean

The opposite of #nil?.

"hello".not_nil?     # -> true
nil.not_nil?         # -> false

Returns:



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# File 'lib/garcon/core_ext/kernel.rb', line 59

def not_nil?
  ! nil?
end

#respond(sym = nil, *args, &blk) ⇒ Object

Like #respond_to? but returns the result of the call if it does respond.

class RespondExample
  def f; "f"; end
end

x = RespondExample.new
x.respond(:f)  # => "f"
x.respond(:g)  # => nil

This method was known as #try until Rails defined #try to be something more akin to #ergo.



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# File 'lib/garcon/core_ext/kernel.rb', line 45

def respond(sym = nil, *args, &blk)
  if sym
    return nil unless respond_to?(sym)
    __send__(sym, *args, &blk)
  else
    MsgFromGod.new(&method(:respond).to_proc)
  end
end

#temporarily(settings) ⇒ Object

Temporarily set variables while yielding a block, then return the variables to their original settings when complete.

temporarily('$VERBOSE'=>false) do
  $VERBOSE.assert == false
end



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# File 'lib/garcon/core_ext/kernel.rb', line 70

def temporarily(settings)
  cache = {}
  settings.each do |var, val|
    cache[var] = eval("#{var}")
    eval("proc{ |v| #{var} = v }").call(val)
  end
  yield
ensure
  cache.each do |var, val|
    eval("proc{ |v| #{var} = v }").call(val)
  end
end

#try(method = nil, *args, &block) ⇒ Object

Invokes the method identified by the symbol method, passing it any arguments and/or the block specified, just like the regular Ruby ‘Object#send` does.

Unlike that method however, a ‘NoMethodError` exception will not be raised and nil will be returned instead, if the receiving object is a `nil` object or NilClass.

For example, without try

@example = Struct.new(:name).new("bob")

@example && @example.name

or:

@example ? @example.name : nil

But with try

@example.try(:name)  #=> "bob"

or

@example.try.name    #=> "bob"

It also accepts arguments and a block, for the method it is trying:

@people.try(:collect){ |p| p.name }



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# File 'lib/garcon/core_ext/kernel.rb', line 113

def try(method=nil, *args, &block)
  if method
    __send__(method, *args, &block)
  else
    self
  end
end