Gem::StreamUI
implements a simple stream based user interface.
Find
mis-matched syntax based on lexical count
Used for detecting missing pairs of elements each keyword needs an end, each ‘{’ needs a ‘}’ etc.
Example:
left_right = LeftRightLexCount.new left_right.count_kw left_right.missing.first # => "end" left_right = LeftRightLexCount.new source = "{ a: b, c: d" # Note missing '}' LexAll.new(source: source).each do |lex| left_right.count_lex(lex) end left_right.missing.first # => "}"
Keeps track of what elements are in the queue in priority and also ensures that when one element engulfs/covers/eats another that the larger element evicts the smaller element
Holds elements in a priority heap on insert
Instead of constantly calling ‘sort!`, put the element where it belongs the first time around
Example:
queue = PriorityQueue.new queue << 33 queue << 44 queue << 1 puts queue.peek # => 44
Capture
parse errors from Ripper
Prism
returns the errors with their messages, but Ripper
does not. To get them we must make a custom subclass.
Example:
puts RipperErrors.new(" def foo").call.errors # => ["syntax error, unexpected end-of-input, expecting ';' or '\\n'"]
Helper methods for both Gem::Installer
and Gem::Uninstaller
Numeric is the class from which all higher-level numeric classes should inherit.
Numeric allows instantiation of heap-allocated objects. Other core numeric classes such as Integer
are implemented as immediates, which means that each Integer
is a single immutable object which is always passed by value.
a = 1 1.object_id == a.object_id #=> true
There can only ever be one instance of the integer 1
, for example. Ruby
ensures this by preventing instantiation. If duplication is attempted, the same instance is returned.
Integer.new(1) #=> NoMethodError: undefined method `new' for Integer:Class 1.dup #=> 1 1.object_id == 1.dup.object_id #=> true
For this reason, Numeric should be used when defining other numeric classes.
Classes which inherit from Numeric must implement coerce
, which returns a two-member Array
containing an object that has been coerced into an instance of the new class and self
(see coerce
).
Inheriting classes should also implement arithmetic operator methods (+
, -
, *
and /
) and the <=>
operator (see Comparable
). These methods may rely on coerce
to ensure interoperability with instances of other numeric classes.
class Tally < Numeric def initialize(string) @string = string end def to_s @string end def to_i @string.size end def coerce(other) [self.class.new('|' * other.to_i), self] end def <=>(other) to_i <=> other.to_i end def +(other) self.class.new('|' * (to_i + other.to_i)) end def -(other) self.class.new('|' * (to_i - other.to_i)) end def *(other) self.class.new('|' * (to_i * other.to_i)) end def /(other) self.class.new('|' * (to_i / other.to_i)) end end tally = Tally.new('||') puts tally * 2 #=> "||||" puts tally > 1 #=> true
First, what’s elsewhere. Class
Numeric:
Inherits from class Object.
Includes module Comparable.
Here, class Numeric provides methods for:
finite?
: Returns true unless self
is infinite or not a number.
infinite?
: Returns -1, nil
or +1, depending on whether self
is -Infinity<tt>, finite, or <tt>+Infinity
.
integer?
: Returns whether self
is an integer.
negative?
: Returns whether self
is negative.
nonzero?
: Returns whether self
is not zero.
positive?
: Returns whether self
is positive.
real?
: Returns whether self
is a real value.
zero?
: Returns whether self
is zero.
<=>
: Returns:
-1 if self
is less than the given value.
0 if self
is equal to the given value.
1 if self
is greater than the given value.
nil
if self
and the given value are not comparable.
eql?
: Returns whether self
and the given value have the same value and type.
%
(aliased as modulo
): Returns the remainder of self
divided by the given value.
-@
: Returns the value of self
, negated.
abs
(aliased as magnitude
): Returns the absolute value of self
.
abs2
: Returns the square of self
.
angle
(aliased as arg
and phase
): Returns 0 if self
is positive, Math::PI otherwise.
ceil
: Returns the smallest number greater than or equal to self
, to a given precision.
coerce
: Returns array [coerced_self, coerced_other]
for the given other value.
conj
(aliased as conjugate
): Returns the complex conjugate of self
.
denominator
: Returns the denominator (always positive) of the Rational
representation of self
.
div
: Returns the value of self
divided by the given value and converted to an integer.
divmod
: Returns array [quotient, modulus]
resulting from dividing self
the given divisor.
fdiv
: Returns the Float
result of dividing self
by the given divisor.
floor
: Returns the largest number less than or equal to self
, to a given precision.
i
: Returns the Complex
object Complex(0, self)
. the given value.
imaginary
(aliased as imag
): Returns the imaginary part of the self
.
numerator
: Returns the numerator of the Rational
representation of self
; has the same sign as self
.
polar
: Returns the array [self.abs, self.arg]
.
quo
: Returns the value of self
divided by the given value.
real
: Returns the real part of self
.
rect
(aliased as rectangular
): Returns the array [self, 0]
.
remainder
: Returns self-arg*(self/arg).truncate
for the given arg
.
round
: Returns the value of self
rounded to the nearest value for the given a precision.
to_int
: Returns the Integer
representation of self
, truncating if necessary.
truncate
: Returns self
truncated (toward zero) to a given precision.
Raised to stop the iteration, in particular by Enumerator#next
. It is rescued by Kernel#loop
.
loop do puts "Hello" raise StopIteration puts "World" end puts "Done!"
produces:
Hello Done!
Raised by exit
to initiate the termination of the script.
The most standard error types are subclasses of StandardError
. A rescue clause without an explicit Exception
class will rescue all StandardErrors (and only those).
def foo raise "Oups" end foo rescue "Hello" #=> "Hello"
On the other hand:
require 'does/not/exist' rescue "Hi"
raises the exception:
LoadError: no such file to load -- does/not/exist
No longer used by internal code.
SystemCallError
is the base class for all low-level platform-dependent errors.
The errors available on the current platform are subclasses of SystemCallError
and are defined in the Errno
module.
File.open("does/not/exist")
raises the exception:
Errno::ENOENT: No such file or directory - does/not/exist
The Addrinfo
class maps struct addrinfo
to ruby. This structure identifies an Internet host and a service.
IPAddr
provides a set of methods to manipulate an IP address. Both IPv4 and IPv6 are supported.
require 'ipaddr' ipaddr1 = IPAddr.new "3ffe:505:2::1" p ipaddr1 #=> #<IPAddr: IPv6:3ffe:0505:0002:0000:0000:0000:0000:0001/ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff> p ipaddr1.to_s #=> "3ffe:505:2::1" ipaddr2 = ipaddr1.mask(48) #=> #<IPAddr: IPv6:3ffe:0505:0002:0000:0000:0000:0000:0000/ffff:ffff:ffff:0000:0000:0000:0000:0000> p ipaddr2.to_s #=> "3ffe:505:2::" ipaddr3 = IPAddr.new "192.168.2.0/24" p ipaddr3 #=> #<IPAddr: IPv4:192.168.2.0/255.255.255.0>
This class implements a pretty printing algorithm. It finds line breaks and nice indentations for grouped structure.
By default, the class assumes that primitive elements are strings and each byte in the strings have single column in width. But it can be used for other situations by giving suitable arguments for some methods:
newline object and space generation block for PrettyPrint.new
optional width argument for PrettyPrint#text
There are several candidate uses:
text formatting using proportional fonts
multibyte characters which has columns different to number of bytes
non-string formatting
Box based formatting?
Other (better) model/algorithm?
Report any bugs at bugs.ruby-lang.org
Christian Lindig, Strictly Pretty, March 2000, lindig.github.io/papers/strictly-pretty-2000.pdf
Philip Wadler, A prettier printer, March 1998, homepages.inf.ed.ac.uk/wadler/topics/language-design.html#prettier
Tanaka Akira <akr@fsij.org>
The class of the singleton object true
.
Several of its methods act as operators:
One other method:
A class that provides the functionality of Kernel#set_trace_func
in a well-structured Object-Oriented API.
Use TracePoint
to gather information specifically for exceptions:
trace = TracePoint.new(:raise) do |tp| p [tp.lineno, tp.event, tp.raised_exception] end #=> #<TracePoint:disabled> trace.enable #=> false 0 / 0 #=> [5, :raise, #<ZeroDivisionError: divided by 0>]
If you don’t specify the types of events you want to listen for, TracePoint
will include all available events.
Note: Do not depend on the current event set, as this list is subject to change. Instead, it is recommended to specify the types of events you want to use.
To filter what is traced, you can pass any of the following as events
:
:line
Execute an expression or statement on a new line.
:class
Start a class or module definition.
:end
Finish a class or module definition.
:call
Call a Ruby
method.
:return
Return from a Ruby
method.
:c_call
Call a C-language routine.
:c_return
Return from a C-language routine.
:raise
Raise an exception.
:rescue
Rescue an exception.
:b_call
Event hook at block entry.
:b_return
Event hook at block ending.
:a_call
Event hook at all calls (call
, b_call
, and c_call
).
:a_return
Event hook at all returns (return
, b_return
, and c_return
).
:thread_begin
Event hook at thread beginning.
:thread_end
Event hook at thread ending.
:fiber_switch
Event hook at fiber switch.
:script_compiled
New Ruby
code compiled (with eval
, load
, or require
).
This module provides a framework for message digest libraries.
You may want to look at OpenSSL::Digest
as it supports more algorithms.
A cryptographic hash function is a procedure that takes data and returns a fixed bit string: the hash value, also known as digest. Hash
functions are also called one-way functions, it is easy to compute a digest from a message, but it is infeasible to generate a message from a digest.
require 'digest' # Compute a complete digest Digest::SHA256.digest 'message' #=> "\xABS\n\x13\xE4Y..." sha256 = Digest::SHA256.new sha256.digest 'message' #=> "\xABS\n\x13\xE4Y..." # Other encoding formats Digest::SHA256.hexdigest 'message' #=> "ab530a13e459..." Digest::SHA256.base64digest 'message' #=> "q1MKE+RZFJgr..." # Compute digest by chunks md5 = Digest::MD5.new md5.update 'message1' md5 << 'message2' # << is an alias for update md5.hexdigest #=> "94af09c09bb9..." # Compute digest for a file sha256 = Digest::SHA256.file 'testfile' sha256.hexdigest
Additionally digests can be encoded in “bubble babble” format as a sequence of consonants and vowels which is more recognizable and comparable than a hexadecimal digest.
require 'digest/bubblebabble' Digest::SHA256.bubblebabble 'message' #=> "xopoh-fedac-fenyh-..."
See the bubble babble specification at web.mit.edu/kenta/www/one/bubblebabble/spec/jrtrjwzi/draft-huima-01.txt.
Digest
algorithms Different digest algorithms (or hash functions) are available:
MD5
See RFC 1321 The MD5
Message-Digest Algorithm
As Digest::RMD160
. See homes.esat.kuleuven.be/~bosselae/ripemd160.html.
SHA1
See FIPS 180 Secure Hash
Standard.
SHA2
familySee FIPS 180 Secure Hash
Standard which defines the following algorithms:
The latest versions of the FIPS publications can be found here: csrc.nist.gov/publications/PubsFIPS.html.
FileTest
implements file test operations similar to those used in File::Stat
. It exists as a standalone module, and its methods are also insinuated into the File
class. (Note that this is not done by inclusion: the interpreter cheats).
URI
is a module providing classes to handle Uniform Resource Identifiers (RFC2396).
Uniform way of handling URIs.
Flexibility to introduce custom URI
schemes.
Flexibility to have an alternate URI::Parser (or just different patterns and regexp’s).
require 'uri' uri = URI("http://foo.com/posts?id=30&limit=5#time=1305298413") #=> #<URI::HTTP http://foo.com/posts?id=30&limit=5#time=1305298413> uri.scheme #=> "http" uri.host #=> "foo.com" uri.path #=> "/posts" uri.query #=> "id=30&limit=5" uri.fragment #=> "time=1305298413" uri.to_s #=> "http://foo.com/posts?id=30&limit=5#time=1305298413"
module URI class RSYNC < Generic DEFAULT_PORT = 873 end register_scheme 'RSYNC', RSYNC end #=> URI::RSYNC URI.scheme_list #=> {"FILE"=>URI::File, "FTP"=>URI::FTP, "HTTP"=>URI::HTTP, # "HTTPS"=>URI::HTTPS, "LDAP"=>URI::LDAP, "LDAPS"=>URI::LDAPS, # "MAILTO"=>URI::MailTo, "RSYNC"=>URI::RSYNC} uri = URI("rsync://rsync.foo.com") #=> #<URI::RSYNC rsync://rsync.foo.com>
A good place to view an RFC spec is www.ietf.org/rfc.html.
Here is a list of all related RFC’s:
Class
tree URI::Generic
(in uri/generic.rb)
URI::File
- (in uri/file.rb)
URI::FTP
- (in uri/ftp.rb)
URI::HTTP
- (in uri/http.rb)
URI::HTTPS
- (in uri/https.rb)
URI::LDAP
- (in uri/ldap.rb)
URI::LDAPS
- (in uri/ldaps.rb)
URI::MailTo
- (in uri/mailto.rb)
URI::Parser - (in uri/common.rb)
URI::REGEXP - (in uri/common.rb)
URI::REGEXP::PATTERN - (in uri/common.rb)
URI::Util - (in uri/common.rb)
URI::Error
- (in uri/common.rb)
URI::InvalidURIError
- (in uri/common.rb)
URI::InvalidComponentError
- (in uri/common.rb)
URI::BadURIError
- (in uri/common.rb)
Akira Yamada <akira@ruby-lang.org>
Akira Yamada <akira@ruby-lang.org> Dmitry V. Sabanin <sdmitry@lrn.ru> Vincent Batts <vbatts@hashbangbash.com>
Copyright © 2001 akira yamada <akira@ruby-lang.org> You can redistribute it and/or modify it under the same term as Ruby
.
OpenURI
is an easy-to-use wrapper for Net::HTTP
, Net::HTTPS and Net::FTP.
It is possible to open an http, https or ftp URL as though it were a file:
URI.open("http://www.ruby-lang.org/") {|f| f.each_line {|line| p line} }
The opened file has several getter methods for its meta-information, as follows, since it is extended by OpenURI::Meta
.
URI.open("http://www.ruby-lang.org/en") {|f| f.each_line {|line| p line} p f.base_uri # <URI::HTTP:0x40e6ef2 URL:http://www.ruby-lang.org/en/> p f.content_type # "text/html" p f.charset # "iso-8859-1" p f.content_encoding # [] p f.last_modified # Thu Dec 05 02:45:02 UTC 2002 }
Additional header fields can be specified by an optional hash argument.
URI.open("http://www.ruby-lang.org/en/", "User-Agent" => "Ruby/#{RUBY_VERSION}", "From" => "foo@bar.invalid", "Referer" => "http://www.ruby-lang.org/") {|f| # ... }
The environment variables such as http_proxy, https_proxy and ftp_proxy are in effect by default. Here we disable proxy:
URI.open("http://www.ruby-lang.org/en/", :proxy => nil) {|f| # ... }
See OpenURI::OpenRead.open
and URI.open
for more on available options.
URI
objects can be opened in a similar way.
uri = URI.parse("http://www.ruby-lang.org/en/") uri.open {|f| # ... }
URI
objects can be read directly. The returned string is also extended by OpenURI::Meta
.
str = uri.read p str.base_uri
Tanaka Akira <akr@m17n.org>