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class Object
# A Ruby-ized realization of the K combinator, courtesy of Mikael Brockman.
#
# def foo
# returning values = [] do
# values << 'bar'
# values << 'baz'
# end
# end
#
# foo # => ['bar', 'baz']
#
def returning(value)
yield
value
end
# Sets $VERBOSE to nil for the duration of the block and back to its original value afterwards.
#
# silence_warnings do
# value = noisy_call # no warning voiced
# end
#
# noisy_call # warning voiced
def silence_warnings
old_verbose, $VERBOSE = $VERBOSE, nil
yield
ensure
$VERBOSE = old_verbose
end
# Sets $VERBOSE to true for the duration of the block and back to its original value afterwards.
def enable_warnings
old_verbose, $VERBOSE = $VERBOSE, true
yield
ensure
$VERBOSE = old_verbose
end
# Silences stderr for the duration of the block.
#
# silence_stderr do
# $stderr.puts 'This will never be seen'
# end
#
# $stderr.puts 'But this will'
def silence_stderr
old_stderr = STDERR.dup
STDERR.reopen(RUBY_PLATFORM =~ /mswin/ ? 'NUL:' : '/dev/null')
STDERR.sync = true
yield
ensure
STDERR.reopen(old_stderr)
end
# Makes backticks behave (somewhat more) similarly on all platforms.
# On win32 `nonexistent_command` raises Errno::ENOENT; on Unix, the
# spawned shell prints a message to stderr and sets $?. We emulate
# Unix on the former but not the latter.
def `(command) #:nodoc:
super
rescue Errno::ENOENT => e
STDERR.puts "#$0: #{e}"
end
# Require a library with fallback to RubyGems. Warnings during library
# loading are silenced to increase signal/noise for application warnings.
def require_library_or_gem(library_name)
silence_warnings do
begin
require library_name
rescue LoadError => cannot_require
# 1. Requiring the module is unsuccessful, maybe it's a gem and nobody required rubygems yet. Try.
begin
require 'rubygems'
rescue LoadError => rubygems_not_installed
raise cannot_require
end
# 2. Rubygems is installed and loaded. Try to load the library again
begin
require library_name
rescue LoadError => gem_not_installed
raise cannot_require
end
end
end
end
end
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