Specifies a Proc object proc to determine completion behavior. It should take input string and return an array of completion candidates.

The default completion is used if proc is nil.

The String that is passed to the Proc depends on the Readline.completer_word_break_characters property. By default the word under the cursor is passed to the Proc. For example, if the input is “foo bar” then only “bar” would be passed to the completion Proc.

Upon successful completion the Readline.completion_append_character will be appended to the input so the user can start working on their next argument.

Examples

Completion for a Static List

require 'readline'

LIST = [
  'search', 'download', 'open',
  'help', 'history', 'quit',
  'url', 'next', 'clear',
  'prev', 'past'
].sort

comp = proc { |s| LIST.grep(/^#{Regexp.escape(s)}/) }

Readline.completion_append_character = " "
Readline.completion_proc = comp

while line = Readline.readline('> ', true)
  p line
end

Completion For Directory Contents

require 'readline'

Readline.completion_append_character = " "
Readline.completion_proc = Proc.new do |str|
  Dir[str+'*'].grep(/^#{Regexp.escape(str)}/)
end

while line = Readline.readline('> ', true)
  p line
end

Autocomplete strategies

When working with auto-complete there are some strategies that work well. To get some ideas you can take a look at the completion.rb file for irb.

The common strategy is to take a list of possible completions and filter it down to those completions that start with the user input. In the above examples Enumerator.grep is used. The input is escaped to prevent Regexp special characters from interfering with the matching.

It may also be helpful to use the Abbrev library to generate completions.

Raises ArgumentError if proc does not respond to the call method.

Returns the completion Proc object.

Returns a new lazy enumerator with the concatenated results of running block once for every element in the lazy enumerator.

["foo", "bar"].lazy.flat_map {|i| i.each_char.lazy}.force
#=> ["f", "o", "o", "b", "a", "r"]

A value x returned by block is decomposed if either of the following conditions is true:

• x responds to both each and force, which means that x is a lazy enumerator.

• x is an array or responds to to_ary.

Otherwise, x is contained as-is in the return value.

[{a:1}, {b:2}].lazy.flat_map {|i| i}.force
#=> [{:a=>1}, {:b=>2}]

Returns the destination encoding as an encoding object.

Returns the destination encoding as an encoding object.

Returns the destination encoding as an Encoding object.

Unmounts dir

Specifies a character to be appended on completion. Nothing will be appended if an empty string (“”) or nil is specified.

For example:

require "readline"

Readline.readline("> ", true)
Readline.completion_append_character = " "

Result:

>
Input "/var/li".

> /var/li
Press TAB key.

> /var/lib
Completes "b" and appends " ". So, you can continuously input "/usr".

> /var/lib /usr

NOTE: Only one character can be specified. When “string” is specified, sets only “s” that is the first.

require "readline"

Readline.completion_append_character = "string"
p Readline.completion_append_character # => "s"

Raises NotImplementedError if the using readline library does not support.

Returns a string containing a character to be appended on completion. The default is a space (“ ”).

Raises NotImplementedError if the using readline library does not support.

When called during a completion (e.g. from within your completion_proc), it will return a string containing the character used to quote the argument being completed, or nil if the argument is unquoted.

When called at other times, it will always return nil.

Note that Readline.completer_quote_characters must be set, or this method will always return nil.

Returns an array of the names of singleton methods for obj. If the optional all parameter is true, the list will include methods in modules included in obj. Only public and protected singleton methods are returned.

module Other
  def three() end
end

class Single
  def Single.four() end
end

a = Single.new

def a.one()
end

class << a
  include Other
  def two()
  end
end

Single.singleton_methods    #=> [:four]
a.singleton_methods(false)  #=> [:two, :one]
a.singleton_methods         #=> [:two, :one, :three]

Similar to method, searches singleton method only.

class Demo
  def initialize(n)
    @iv = n
  end
  def hello()
    "Hello, @iv = #{@iv}"
  end
end

k = Demo.new(99)
def k.hi
  "Hi, @iv = #{@iv}"
end
m = k.singleton_method(:hi)
m.call   #=> "Hi, @iv = 99"
m = k.singleton_method(:hello) #=> NameError

Hadamard product

Matrix[[1,2], [3,4]].hadamard_product(Matrix[[1,2], [3,2]])
  => 1  4
     9  8

Returns the inner product of this vector with the other.

Vector[4,7].inner_product Vector[10,1]  => 47

Returns the cross product of this vector with the others.

Vector[1, 0, 0].cross_product Vector[0, 1, 0]   => Vector[0, 0, 1]

It is generalized to other dimensions to return a vector perpendicular to the arguments.

Vector[1, 2].cross_product # => Vector[-2, 1]
Vector[1, 0, 0, 0].cross_product(
   Vector[0, 1, 0, 0],
   Vector[0, 0, 1, 0]
)  #=> Vector[0, 0, 0, 1]

Returns an Array of methods names which have the option opt.

p FileUtils.collect_method(:preserve) #=> ["cp", "cp_r", "copy", "install"]

Initializes the MonitorMixin after being included in a class or when an object has been extended with the MonitorMixin

Returns the Base64-encoded version of bin. This method complies with RFC 4648. No line feeds are added.

Returns the convertible integer type of the given type. You may optionally specify additional headers to search in for the type. convertible means actually the same type, or typedef’d from the same type.

If the type is an integer type and the convertible type is found, the following macros are passed as preprocessor constants to the compiler using the type name, in uppercase.

• TYPEOF_, followed by the type name, followed by =X where “X” is the found convertible type name.

• TYP2NUM and NUM2TYP, where TYP is the type name in uppercase with replacing an _t suffix with “T”, followed by =X where “X” is the macro name to convert type to an Integer object, and vice versa.

For example, if foobar_t is defined as unsigned long, then convertible_int("foobar_t") would return “unsigned long”, and define these macros:

#define TYPEOF_FOOBAR_T unsigned long
#define FOOBART2NUM ULONG2NUM
#define NUM2FOOBART NUM2ULONG

| RelationalExpr (‘<’ | ‘>’ | ‘<=’ | ‘>=’) AdditiveExpr | AdditiveExpr