зеркало из https://github.com/github/ruby.git
* doc/re.rb: New document for Ruby's fork of Oniguruma.
written by Run Paint Run Run [ruby-core:25420] * re.c: import document in doc/re.rb. * .document: add doc/re.rb. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@24973 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
naruse
Родитель
6023a79deb
Коммит
63c7ca40d8
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@ -14,3 +14,5 @@ lib
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# and some of the ext/ directory (which has its own .document file)
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ext
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doc/re.rb
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@ -1,3 +1,12 @@
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Thu Sep 17 09:37:28 2009 NARUSE, Yui <naruse@ruby-lang.org>
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* doc/re.rb: New document for Ruby's fork of Oniguruma.
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written by Run Paint Run Run [ruby-core:25420]
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* re.c: import document in doc/re.rb.
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* .document: add doc/re.rb.
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Thu Sep 17 06:03:40 2009 Marc-Andre Lafortune <ruby-core@marc-andre.ca>
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* lib/matrix.rb (Matrix#rank): Two bug fixes. One made
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@ -0,0 +1,584 @@
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module Doc
|
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# Regular expressions (<i>regexp</i>s) are patterns which describe the
|
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# contents of a string. They're used for testing whether a string contains a
|
||||
# given pattern, or extracting the portions that match. They are created
|
||||
# with the <tt>/</tt><i>pat</i><tt>/</tt> and
|
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# <tt>%r{</tt><i>pat</i><tt>}</tt> literals or the <tt>Regexp.new</tt>
|
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# constructor.
|
||||
#
|
||||
# A regexp is usually delimited with forward slashes (<tt>/</tt>). For
|
||||
# example:
|
||||
#
|
||||
# /hay/ =~ 'haystack' #=> 0
|
||||
# /y/.match('haystack') #=> #<MatchData "y">
|
||||
#
|
||||
# If a string contains the pattern it is said to <i>match</i>. A literal
|
||||
# string matches itself.
|
||||
#
|
||||
# # 'haystack' does not contain the pattern 'needle', so doesn't match.
|
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# /needle/.match('haystack') #=> nil
|
||||
# # 'haystack' does contain the pattern 'hay', so it matches
|
||||
# /hay/.match('haystack') #=> #<MatchData "hay">
|
||||
#
|
||||
# Specifically, <tt>/st/</tt> requires that the string contains the letter
|
||||
# _s_ followed by the letter _t_, so it matches _haystack_, also.
|
||||
#
|
||||
# == Metacharacters and Escapes
|
||||
#
|
||||
# The following are <i>metacharacters</i> <tt>(</tt>, <tt>)</tt>,
|
||||
# <tt>[</tt>, <tt>]</tt>, <tt>{</tt>, <tt>}</tt>, <tt>.</tt>, <tt>?</tt>,
|
||||
# <tt>+</tt>, <tt>*</tt>. They have a specific meaning when appearing in a
|
||||
# pattern. To match them literally they must be backslash-escaped. To match
|
||||
# a backslash literally backslash-escape that: <tt>\\\\\\</tt>.
|
||||
#
|
||||
# /1 \+ 2 = 3\?/.match('Does 1 + 2 = 3?') #=> #<MatchData "1 + 2 = 3?">
|
||||
#
|
||||
# Patterns behave like double-quoted strings so can contain the same
|
||||
# backslash escapes.
|
||||
#
|
||||
# /\s\u{6771 4eac 90fd}/.match("Go to 東京都")
|
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# #=> #<MatchData " 東京都">
|
||||
#
|
||||
# Arbitrary Ruby expressions can be embedded into patterns with the
|
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# <tt>#{...}</tt> construct.
|
||||
#
|
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# place = "東京都"
|
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# /#{place}/.match("Go to 東京都")
|
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# #=> #<MatchData "東京都">
|
||||
#
|
||||
# == Character Classes
|
||||
#
|
||||
# A <i>character class</i> is delimited with square brackets (<tt>[</tt>,
|
||||
# <tt>]</tt>) and lists characters that may appear at that point in the
|
||||
# match. <tt>/[ab]/</tt> means _a_ or _b_, as opposed to <tt>/ab/</tt> which
|
||||
# means _a_ followed by _b_.
|
||||
#
|
||||
# /W[aeiou]rd/.match("Word") #=> #<MatchData "Word">
|
||||
#
|
||||
# Within a character class the hyphen (<tt>-</tt>) is a metacharacter
|
||||
# denoting an inclusive range of characters. <tt>[abcd]</tt> is equivalent
|
||||
# to <tt>[a-d]</tt>. A range can be followed by another range, so
|
||||
# <tt>[abcdwxyz]</tt> is equivalent to <tt>[a-dw-z]</tt>. The order in which
|
||||
# ranges or individual characters appear inside a character class is
|
||||
# irrelevant.
|
||||
#
|
||||
# /[0-9a-f]/.match('9f') #=> #<MatchData "9">
|
||||
# /[9f]/.match('9f') #=> #<MatchData "9">
|
||||
#
|
||||
# If the first character of a character class is a caret (<tt>^</tt>) the
|
||||
# class is inverted: it matches any character _except_ those named.
|
||||
#
|
||||
# /[^a-eg-z]/.match('f') #=> #<MatchData "f">
|
||||
#
|
||||
# A character class may contain another character class. By itself this
|
||||
# isn't useful because <tt>[a-z[0-9]]</tt> describes the same set as
|
||||
# <tt>[a-z0-9]</tt>. However, character classes also support the <tt>&&</tt>
|
||||
# operator which performs set intersection on its arguments. The two can be
|
||||
# combined as follows:
|
||||
#
|
||||
# /[a-w&&[^c-g]z]/ # ([a-w] AND ([^c-g] OR z))
|
||||
# # This is equivalent to:
|
||||
# /[abh-w]/
|
||||
#
|
||||
# The following metacharacters also behave like character classes:
|
||||
#
|
||||
# * <tt>/./</tt> - Any character except a newline.
|
||||
# * <tt>/./m</tt> - Any character (the +m+ modifier enables multiline mode)
|
||||
# * <tt>/\w/</tt> - A word character (<tt>[a-zA-Z0-9_]</tt>)
|
||||
# * <tt>/\W/</tt> - A non-word character (<tt>[^a-zA-Z0-9_]</tt>)
|
||||
# * <tt>/\d/</tt> - A digit character (<tt>[0-9]</tt>)
|
||||
# * <tt>/\D/</tt> - A non-digit character (<tt>[^0-9]</tt>)
|
||||
# * <tt>/\h/</tt> - A hexdigit character (<tt>[0-9a-fA-F]</tt>)
|
||||
# * <tt>/\H/</tt> - A non-hexdigit character (<tt>[^0-9a-fA-F]</tt>)
|
||||
# * <tt>/\s/</tt> - A whitespace character: <tt>/[ \t\r\n\f]/</tt>
|
||||
# * <tt>/\S/</tt> - A non-whitespace character: <tt>/[^ \t\r\n\f]/</tt>
|
||||
#
|
||||
# POSIX <i>bracket expressions</i> are also similar to character classes.
|
||||
# They provide a portable alternative to the above, with the added benefit
|
||||
# that they encompass non-ASCII characters. For instance, <tt>/\d/</tt>
|
||||
# matches only the ASCII decimal digits (0-9); whereas <tt>/[[:digit:]]/</tt>
|
||||
# matches any character in the Unicode _Nd_ category.
|
||||
#
|
||||
# * <tt>/[[:alnum:]]/</tt> - Alphabetic and numeric character
|
||||
# * <tt>/[[:alpha:]]/</tt> - Alphabetic character
|
||||
# * <tt>/[[:blank:]]/</tt> - Space or tab
|
||||
# * <tt>/[[:cntrl:]]/</tt> - Control character
|
||||
# * <tt>/[[:digit:]]/</tt> - Digit
|
||||
# * <tt>/[[:graph:]]/</tt> - Non-blank character (excludes spaces, control
|
||||
# characters, and similar)
|
||||
# * <tt>/[[:lower:]]/</tt> - Lowercase alphabetical character
|
||||
# * <tt>/[[:print:]]/</tt> - Like [:graph:], but includes the space character
|
||||
# * <tt>/[[:punct:]]/</tt> - Punctuation character
|
||||
# * <tt>/[[:space:]]/</tt> - Whitespace character (<tt>[:blank:]</tt>, newline,
|
||||
# carriage return, etc.)
|
||||
# * <tt>/[[:upper:]]/</tt> - Uppercase alphabetical
|
||||
# * <tt>/[[:xdigit:]]/</tt> - Digit allowed in a hexadecimal number (i.e.,
|
||||
# 0-9a-fA-F)
|
||||
#
|
||||
# Ruby also supports the following non-POSIX character classes:
|
||||
#
|
||||
# * <tt>/[[:word:]]/</tt> - A character in one of the following Unicode
|
||||
# general categories _Letter_, _Mark_, _Number_,
|
||||
# <i>Connector_Punctuation<i/i>
|
||||
# * <tt>/[[:ascii:]]/</tt> - A character in the ASCII character set
|
||||
#
|
||||
# # U+06F2 is "EXTENDED ARABIC-INDIC DIGIT TWO"
|
||||
# /[[:digit:]]/.match("\u06F2") #=> #<MatchData "\u{06F2}">
|
||||
# /[[:upper:]][[:lower:]]/.match("Hello") #=> #<MatchData "He">
|
||||
# /[[:xdigit:]][[:xdigit:]]/.match("A6") #=> #<MatchData "A6">
|
||||
#
|
||||
# == Repetition
|
||||
#
|
||||
# The constructs described so far match a single character. They can be
|
||||
# followed by a repetition metacharacter to specify how many times they need
|
||||
# to occur. Such metacharacters are called <i>quantifiers</i>.
|
||||
#
|
||||
# * <tt>*</tt> - Zero or more times
|
||||
# * <tt>+</tt> - One or more times
|
||||
# * <tt>?</tt> - Zero or one times (optional)
|
||||
# * <tt>{</tt><i>n</i><tt>}</tt> - Exactly <i>n</i> times
|
||||
# * <tt>{</tt><i>n</i><tt>,}</tt> - <i>n</i> or more times
|
||||
# * <tt>{,</tt><i>m</i><tt>}</tt> - <i>m</i> or less times
|
||||
# * <tt>{</tt><i>n</i><tt>,</tt><i>m</i><tt>}</tt> - At least <i>n</i> and
|
||||
# at most <i>m</i> times
|
||||
#
|
||||
# # At least one uppercase character ('H'), at least one lowercase
|
||||
# # character ('e'), two 'l' characters, then one 'o'
|
||||
# "Hello".match(/[[:upper:]]+[[:lower:]]+l{2}o/) #=> #<MatchData "Hello">
|
||||
#
|
||||
# Repetition is <i>greedy</i> by default: as many occurrences as possible
|
||||
# are matched while still allowing the overall match to succeed. By
|
||||
# contrast, <i>lazy</i> matching makes the minimal amount of matches
|
||||
# necessary for overall success. A greedy metacharacter can be made lazy by
|
||||
# following it with <tt>?</tt>.
|
||||
#
|
||||
# # Both patterns below match the string. The fist uses a greedy
|
||||
# # quantifier so '.+' matches '<a><b>'; the second uses a lazy
|
||||
# # quantifier so '.+?' matches '<a>'.
|
||||
# /<.+>/.match("<a><b>") #=> #<MatchData "<a><b>">
|
||||
# /<.+?>/.match("<a><b>") #=> #<MatchData "<a>">
|
||||
#
|
||||
# A quantifier followed by <tt>+</tt> matches <i>possessively</i>: once it
|
||||
# has matched it does not backtrack. They behave like greedy quantifiers,
|
||||
# but having matched they refuse to "give up" their match even if this
|
||||
# jeopardises the overall match.
|
||||
#
|
||||
# == Capturing
|
||||
#
|
||||
# Parentheses can be used for <i>capturing</i>. The text enclosed by the
|
||||
# <i>n</i><sup>th</sup> group of parentheses can be subsequently referred to
|
||||
# with <i>n</i>. Within a pattern use the <i>backreference</i>
|
||||
# <tt>\</tt><i>n</i>; outside of the pattern use
|
||||
# <tt>MatchData[</tt><i>n</i><tt>]</tt>.
|
||||
#
|
||||
# # 'at' is captured by the first group of parentheses, then referred to
|
||||
# # later with \1
|
||||
# /[csh](..) [csh]\1 in/.match("The cat sat in the hat")
|
||||
# #=> #<MatchData "cat sat in" 1:"at">
|
||||
# # Regexp#match returns a MatchData object which makes the captured
|
||||
# # text available with its #[] method.
|
||||
# /[csh](..) [csh]\1 in/.match("The cat sat in the hat")[1] #=> 'at'
|
||||
#
|
||||
# Capture groups can be referred to by name when defined with the
|
||||
# <tt>(?<</tt><i>name</i><tt>>)</tt> or <tt>(?'</tt><i>name</i><tt>')</tt>
|
||||
# constructs.
|
||||
#
|
||||
# /\$(?<dollars>\d+)\.(?<cents>\d+)/.match("$3.67")
|
||||
# => #<MatchData "$3.67" dollars:"3" cents:"67">
|
||||
# /\$(?<dollars>\d+)\.(?<cents>\d+)/.match("$3.67")[:dollars] #=> "3"
|
||||
#
|
||||
# Named groups can be backreferenced with <tt>\k<</tt><i>name</i><tt>></tt>,
|
||||
# where _name_ is the group name.
|
||||
#
|
||||
# /(?<vowel>[aeiou]).\k<vowel>.\k<vowel>/.match('ototomy')
|
||||
# #=> #<MatchData "ototo" vowel:"o">
|
||||
#
|
||||
# *Note*: A regexp can't use named backreferences and numbered
|
||||
# backreferences simultaneously.
|
||||
#
|
||||
# When named capture groups are used with a literal regexp on the left-hand
|
||||
# side of an expression and the <tt>=~</tt> operator, the captured text is
|
||||
# also assigned to local variables with corresponding names.
|
||||
#
|
||||
# /\$(?<dollars>\d+)\.(?<cents>\d+)/ =~ "$3.67" #=> 0
|
||||
# dollars #=> "3"
|
||||
#
|
||||
# == Grouping
|
||||
#
|
||||
# Parentheses also <i>group</i> the terms they enclose, allowing them to be
|
||||
# quantified as one <i>atomic</i> whole.
|
||||
#
|
||||
# # The pattern below matches a vowel followed by 2 word characters:
|
||||
# # 'aen'
|
||||
# /[aeiou]\w{2}/.match("Caenorhabditis elegans") #=> #<MatchData "aen">
|
||||
# # Whereas the following pattern matches a vowel followed by a word
|
||||
# # character, twice, i.e. <tt>[aeiou]\w[aeiou]\w</tt>: 'enor'.
|
||||
# /([aeiou]\w){2}/.match("Caenorhabditis elegans")
|
||||
# #=> #<MatchData "enor" 1:"or">
|
||||
#
|
||||
# The <tt>(?:</tt>...<tt>)</tt> construct provides grouping without
|
||||
# capturing. That is, it combines the terms it contains into an atomic whole
|
||||
# without creating a backreference. This benefits performance at the slight
|
||||
# expense of readabilty.
|
||||
#
|
||||
# # The group of parentheses captures 'n' and the second 'ti'. The
|
||||
# # second group is referred to later with the backreference \2
|
||||
# /I(n)ves(ti)ga\2ons/.match("Investigations")
|
||||
# #=> #<MatchData "Investigations" 1:"n" 2:"ti">
|
||||
# # The first group of parentheses is now made non-capturing with '?:',
|
||||
# # so it still matches 'n', but doesn't create the backreference. Thus,
|
||||
# # the backreference \1 now refers to 'ti'.
|
||||
# /I(?:n)ves(ti)ga\1ons/.match("Investigations")
|
||||
# #=> #<MatchData "Investigations" 1:"ti">
|
||||
#
|
||||
# === Atomic Grouping
|
||||
#
|
||||
# Grouping can be made <i>atomic</i> with
|
||||
# <tt>(?></tt><i>pat</i><tt>)</tt>. This causes the subexpression <i>pat</i>
|
||||
# to be matched independently of the rest of the expression such that what
|
||||
# it matches becomes fixed for the remainder of the match, unless the entire
|
||||
# subexpression must be abandoned and subsequently revisited. In this
|
||||
# way <i>pat</i> is treated as a non-divisible whole. Atomic grouping is
|
||||
# typically used to optimise patterns so as to prevent the regular
|
||||
# expression engine from backtracking needlesly.
|
||||
#
|
||||
# # The <tt>"</tt> in the pattern below matches the first character of
|
||||
# # the string, then <tt>.*</tt> matches <i>Quote"</i>. This causes the
|
||||
# # overall match to fail, so the text matched by <tt>.*</tt> is
|
||||
# # backtracked by one position, which leaves the final character of the
|
||||
# # string available to match <tt>"</tt>
|
||||
# /".*"/.match('"Quote"') #=> #<MatchData "\"Quote\"">
|
||||
# # If <tt>.*</tt> is grouped atomically, it refuses to backtrack
|
||||
# # <i>Quote"</i>, even though this means that the overall match fails
|
||||
# /"(?>.*)"/.match('"Quote"') #=> nil
|
||||
#
|
||||
# == Subexpression Calls
|
||||
#
|
||||
# The <tt>\g<</tt><i>name</i><tt>></tt> syntax matches the previous
|
||||
# subexpression named _name_, which can be a group name or number, again.
|
||||
# This differs from backreferences in that it re-executes the group rather
|
||||
# than simply trying to re-match the same text.
|
||||
#
|
||||
# # Matches a <i>(</i> character and assigns it to the <tt>paren</tt>
|
||||
# # group, tries to call that the <tt>paren</tt> sub-expression again
|
||||
# # but fails, then matches a literal <i>)</i>.
|
||||
# /\A(?<paren>\(\g<paren>*\))*\z/ =~ '()'
|
||||
#
|
||||
#
|
||||
# /\A(?<paren>\(\g<paren>*\))*\z/ =~ '(())' #=> 0
|
||||
# # ^1
|
||||
# # ^2
|
||||
# # ^3
|
||||
# # ^4
|
||||
# # ^5
|
||||
# # ^6
|
||||
# # ^7
|
||||
# # ^8
|
||||
# # ^9
|
||||
# # ^10
|
||||
#
|
||||
# 1. Matches at the beginning of the string, i.e. before the first
|
||||
# character.
|
||||
# 2. Enters a named capture group called <tt>paren</tt>
|
||||
# 3. Matches a literal <i>(</i>, the first character in the string
|
||||
# 4. Calls the <tt>paren</tt> group again, i.e. recurses back to the
|
||||
# second step
|
||||
# 5. Re-enters the <tt>paren</tt> group
|
||||
# 6. Matches a literal <i>(</i>, the second character in the
|
||||
# string
|
||||
# 7. Try to call <tt>paren</tt> a third time, but fail because
|
||||
# doing so would prevent an overall successful match
|
||||
# 8. Match a literal <i>)</i>, the third character in the string.
|
||||
# Marks the end of the second recursive call
|
||||
# 9. Match a literal <i>)</i>, the fourth character in the string
|
||||
# 10. Match the end of the string
|
||||
#
|
||||
# == Alternation
|
||||
#
|
||||
# The vertical bar metacharacter (<tt>|</tt>) combines two expressions into
|
||||
# a single one that matches either of the expressions. Each expression is an
|
||||
# <i>alternative</i>.
|
||||
#
|
||||
# /\w(and|or)\w/.match("Feliformia") #=> #<MatchData "form" 1:"or">
|
||||
# /\w(and|or)\w/.match("furandi") #=> #<MatchData "randi" 1:"and">
|
||||
# /\w(and|or)\w/.match("dissemblance") #=> nil
|
||||
#
|
||||
# == Character Properties
|
||||
#
|
||||
# The <tt>\p{}</tt> construct matches characters with the named property,
|
||||
# much like POSIX bracket classes.
|
||||
#
|
||||
# * <tt>/\p{Alnum}/</tt> - Alphabetic and numeric character
|
||||
# * <tt>/\p{Alpha}/</tt> - Alphabetic character
|
||||
# * <tt>/\p{Blank}/</tt> - Space or tab
|
||||
# * <tt>/\p{Cntrl}/</tt> - Control character
|
||||
# * <tt>/\p{Digit}/</tt> - Digit
|
||||
# * <tt>/\p{Graph}/</tt> - Non-blank character (excludes spaces, control
|
||||
# characters, and similar)
|
||||
# * <tt>/\p{Lower}/</tt> - Lowercase alphabetical character
|
||||
# * <tt>/\p{Print}/</tt> - Like <tt>\p{Graph}</tt>, but includes the space character
|
||||
# * <tt>/\p{Punct}/</tt> - Punctuation character
|
||||
# * <tt>/\p{Space}/</tt> - Whitespace character (<tt>[:blank:]</tt>, newline,
|
||||
# carriage return, etc.)
|
||||
# * <tt>/\p{Upper}/</tt> - Uppercase alphabetical
|
||||
# * <tt>/\p{XDigit}/</tt> - Digit allowed in a hexadecimal number (i.e., 0-9a-fA-F)
|
||||
# * <tt>/\p{Word}/</tt> - A member of one of the following Unicode general
|
||||
# category <i>Letter</i>, <i>Mark</i>, <i>Number</i>,
|
||||
# <i>Connector\_Punctuation</i>
|
||||
# * <tt>/\p{ASCII}/</tt> - A character in the ASCII character set
|
||||
# * <tt>/\p{Any}/</tt> - Any Unicode character (including unassigned
|
||||
# characters)
|
||||
# * <tt>/\p{Assigned}/</tt> - An assigned character
|
||||
#
|
||||
# A Unicode character's <i>General Category</i> value can also be matched
|
||||
# with <tt>\p{</tt><i>Ab</i><tt>}</tt> where <i>Ab</i> is the category's
|
||||
# abbreviation as described below:
|
||||
#
|
||||
# * <tt>/\p{L}/</tt> - 'Letter'
|
||||
# * <tt>/\p{Ll}/</tt> - 'Letter: Lowercase'
|
||||
# * <tt>/\p{Lm}/</tt> - 'Letter: Mark'
|
||||
# * <tt>/\p{Lo}/</tt> - 'Letter: Other'
|
||||
# * <tt>/\p{Lt}/</tt> - 'Letter: Titlecase'
|
||||
# * <tt>/\p{Lu}/</tt> - 'Letter: Uppercase
|
||||
# * <tt>/\p{Lo}/</tt> - 'Letter: Other'
|
||||
# * <tt>/\p{M}/</tt> - 'Mark'
|
||||
# * <tt>/\p{Mn}/</tt> - 'Mark: Nonspacing'
|
||||
# * <tt>/\p{Mc}/</tt> - 'Mark: Spacing Combining'
|
||||
# * <tt>/\p{Me}/</tt> - 'Mark: Enclosing'
|
||||
# * <tt>/\p{N}/</tt> - 'Number'
|
||||
# * <tt>/\p{Nd}/</tt> - 'Number: Decimal Digit'
|
||||
# * <tt>/\p{Nl}/</tt> - 'Number: Letter'
|
||||
# * <tt>/\p{No}/</tt> - 'Number: Other'
|
||||
# * <tt>/\p{P}/</tt> - 'Punctuation'
|
||||
# * <tt>/\p{Pc}/</tt> - 'Punctuation: Connector'
|
||||
# * <tt>/\p{Pd}/</tt> - 'Punctuation: Dash'
|
||||
# * <tt>/\p{Ps}/</tt> - 'Punctuation: Open'
|
||||
# * <tt>/\p{Pe}/</tt> - 'Punctuation: Close'
|
||||
# * <tt>/\p{Pi}/</tt> - 'Punctuation: Initial Quote'
|
||||
# * <tt>/\p{Pf}/</tt> - 'Punctuation: Final Quote'
|
||||
# * <tt>/\p{Po}/</tt> - 'Punctuation: Other'
|
||||
# * <tt>/\p{S}/</tt> - 'Symbol'
|
||||
# * <tt>/\p{Sm}/</tt> - 'Symbol: Math'
|
||||
# * <tt>/\p{Sc}/</tt> - 'Symbol: Currency'
|
||||
# * <tt>/\p{Sc}/</tt> - 'Symbol: Currency'
|
||||
# * <tt>/\p{Sk}/</tt> - 'Symbol: Modifier'
|
||||
# * <tt>/\p{So}/</tt> - 'Symbol: Other'
|
||||
# * <tt>/\p{Z}/</tt> - 'Separator'
|
||||
# * <tt>/\p{Zs}/</tt> - 'Separator: Space'
|
||||
# * <tt>/\p{Zl}/</tt> - 'Separator: Line'
|
||||
# * <tt>/\p{Zp}/</tt> - 'Separator: Paragraph'
|
||||
# * <tt>/\p{C}/</tt> - 'Other'
|
||||
# * <tt>/\p{Cc}/</tt> - 'Other: Control'
|
||||
# * <tt>/\p{Cf}/</tt> - 'Other: Format'
|
||||
# * <tt>/\p{Cn}/</tt> - 'Other: Not Assigned'
|
||||
# * <tt>/\p{Co}/</tt> - 'Other: Private Use'
|
||||
# * <tt>/\p{Cs}/</tt> - 'Other: Surrogate'
|
||||
#
|
||||
# Lastly, <tt>\p{}</tt> matches a character's Unicode <i>script</i>. The
|
||||
# following scripts are supported: <i>Arabic</i>, <i>Armenian</i>,
|
||||
# <i>Balinese</i>, <i>Bengali</i>, <i>Bopomofo</i>, <i>Braille</i>,
|
||||
# <i>Buginese</i>, <i>Buhid</i>, <i>Canadian_Aboriginal</i>, <i>Carian</i>,
|
||||
# <i>Cham</i>, <i>Cherokee</i>, <i>Common</i>, <i>Coptic</i>,
|
||||
# <i>Cuneiform</i>, <i>Cypriot</i>, <i>Cyrillic</i>, <i>Deseret</i>,
|
||||
# <i>Devanagari</i>, <i>Ethiopic</i>, <i>Georgian</i>, <i>Glagolitic</i>,
|
||||
# <i>Gothic</i>, <i>Greek</i>, <i>Gujarati</i>, <i>Gurmukhi</i>, <i>Han</i>,
|
||||
# <i>Hangul</i>, <i>Hanunoo</i>, <i>Hebrew</i>, <i>Hiragana</i>,
|
||||
# <i>Inherited</i>, <i>Kannada</i>, <i>Katakana</i>, <i>Kayah_Li</i>,
|
||||
# <i>Kharoshthi</i>, <i>Khmer</i>, <i>Lao</i>, <i>Latin</i>, <i>Lepcha</i>,
|
||||
# <i>Limbu</i>, <i>Linear_B</i>, <i>Lycian</i>, <i>Lydian</i>,
|
||||
# <i>Malayalam</i>, <i>Mongolian</i>, <i>Myanmar</i>, <i>New_Tai_Lue</i>,
|
||||
# <i>Nko</i>, <i>Ogham</i>, <i>Ol_Chiki</i>, <i>Old_Italic</i>,
|
||||
# <i>Old_Persian</i>, <i>Oriya</i>, <i>Osmanya</i>, <i>Phags_Pa</i>,
|
||||
# <i>Phoenician</i>, <i>Rejang</i>, <i>Runic</i>, <i>Saurashtra</i>,
|
||||
# <i>Shavian</i>, <i>Sinhala</i>, <i>Sundanese</i>, <i>Syloti_Nagri</i>,
|
||||
# <i>Syriac</i>, <i>Tagalog</i>, <i>Tagbanwa</i>, <i>Tai_Le</i>,
|
||||
# <i>Tamil</i>, <i>Telugu</i>, <i>Thaana</i>, <i>Thai</i>, <i>Tibetan</i>,
|
||||
# <i>Tifinagh</i>, <i>Ugaritic</i>, <i>Vai</i>, and <i>Yi</i>.
|
||||
#
|
||||
# # Unicode codepoint U+06E9 is named "ARABIC PLACE OF SAJDAH" and
|
||||
# # belongs to the Arabic script.
|
||||
# /\p{Arabic}/.match("\u06E9") #=> #<MatchData "\u06E9">
|
||||
#
|
||||
# All character properties can be inverted by prefixing their name with a
|
||||
# caret (<tt>^</tt>).
|
||||
#
|
||||
# # Letter 'A' is not in the Unicode Ll (Letter; Lowercase) category, so
|
||||
# # this match succeeds
|
||||
# /\p{^Ll}/.match("A") #=> #<MatchData "A">
|
||||
#
|
||||
# == Anchors
|
||||
#
|
||||
# Anchors are metacharacter that match the zero-width positions between
|
||||
# characters, <i>anchoring</i> the match to a specific position.
|
||||
#
|
||||
# * <tt>^</tt> - Matches beginning of line
|
||||
# * <tt>$</tt> - Matches end of line
|
||||
# * <tt>\A</tt> - Matches beginning of string.
|
||||
# * <tt>\Z</tt> - Matches end of string. If string ends with a newline,
|
||||
# it matches just before newline
|
||||
# * <tt>\z</tt> - Matches end of string
|
||||
# * <tt>\G</tt> - Matches point where last match finished
|
||||
# * <tt>\b</tt> - Matches word boundaries when outside brackets; backspace
|
||||
# (0x08) inside brackets
|
||||
# * <tt>\B</tt> - Matches non-word boundaries
|
||||
# * <tt>(?=</tt><i>pat</i><tt>)</tt> - <i>Positive lookahead</i> assertion:
|
||||
# ensures that the following characters match <i>pat</i>, but doesn't
|
||||
# include those characters in the matched text
|
||||
# * <tt>(?!</tt><i>pat</i><tt>)</tt> - <i>Negative lookahead</i> assertion:
|
||||
# ensures that the following characters do not match <i>pat</i>, but
|
||||
# doesn't include those characters in the matched text
|
||||
# * <tt>(?<=</tt><i>pat</i><tt>)</tt> - <i>Positive lookbehind</i>
|
||||
# assertion: ensures that the preceding characters match <i>pat</i>, but
|
||||
# doesn't include those characters in the matched text
|
||||
# * <tt>(?<!</tt><i>pat</i><tt>)</tt> - <i>Negative lookbehind</i>
|
||||
# assertion: ensures that the preceding characters do not match
|
||||
# <i>pat</i>, but doesn't include those characters in the matched text
|
||||
#
|
||||
# # If a pattern isn't anchored it can begin at any point in the string
|
||||
# /real/.match("surrealist") #=> #<MatchData "real">
|
||||
# # Anchoring the pattern to the beginning of the string forces the
|
||||
# # match to start there. 'real' doesn't occur at the beginning of the
|
||||
# # string, so now the match fails
|
||||
# /\Areal/.match("surrealist") #=> nil
|
||||
# # The match below fails because although 'Demand' contains 'and', the
|
||||
# pattern does not occur at a word boundary.
|
||||
# /\band/.match("Demand")
|
||||
# # Whereas in the following example 'and' has been anchored to a
|
||||
# # non-word boundary so instead of matching the first 'and' it matches
|
||||
# # from the fourth letter of 'demand' instead
|
||||
# /\Band.+/.match("Supply and demand curve") #=> #<MatchData "and curve">
|
||||
# # The pattern below uses positive lookahead and positive lookbehind to
|
||||
# # match text appearing in <b></b> tags without including the tags in the
|
||||
# # match
|
||||
# /(?<=<b>)\w+(?=<\/b>)/.match("Fortune favours the <b>bold</b>")
|
||||
# #=> #<MatchData "bold">
|
||||
#
|
||||
# == Options
|
||||
#
|
||||
# The end delimiter for a regexp can be followed by one or more single-letter
|
||||
# options which control how the pattern can match.
|
||||
#
|
||||
# * <tt>/pat/i</tt> - Ignore case
|
||||
# * <tt>/pat/m</tt> - Treat a newline as a character matched by <tt>.</tt>
|
||||
# * <tt>/pat/x</tt> - Ignore whitespace and comments in the pattern
|
||||
# * <tt>/pat/o</tt> - Perform <tt>#{}</tt> interpolation only once
|
||||
#
|
||||
# <tt>i</tt>, <tt>m</tt>, and <tt>x</tt> can also be applied on the
|
||||
# subexpression level with the
|
||||
# <tt>(?</tt><i>on</i><tt>-</tt><i>off</i><tt>)</tt> construct, which
|
||||
# enables options <i>on</i>, and disables options <i>off</i> for the
|
||||
# expression enclosed by the parentheses.
|
||||
#
|
||||
# /a(?i:b)c/.match('aBc') #=> #<MatchData "aBc">
|
||||
# /a(?i:b)c/.match('abc') #=> #<MatchData "abc">
|
||||
#
|
||||
# == Free-Spacing Mode and Comments
|
||||
#
|
||||
# As mentioned above, the <tt>x</tt> option enables <i>free-spacing</i>
|
||||
# mode. Literal white space inside the pattern is ignored, and the
|
||||
# octothorpe (<tt>#</tt>) character introduces a comment until the end of
|
||||
# the line. This allows the components of the pattern to be organised in a
|
||||
# potentially more readable fashion.
|
||||
#
|
||||
# # A contrived pattern to match a number with optional decimal places
|
||||
# float_pat = /\A
|
||||
# [[:digit:]]+ # 1 or more digits before the decimal point
|
||||
# (\. # Decimal point
|
||||
# [[:digit:]]+ # 1 or more digits after the decimal point
|
||||
# )? # The decimal point and following digits are optional
|
||||
# \Z/x
|
||||
# float_pat.match('3.14') #=> #<MatchData "3.14" 1:".14">
|
||||
#
|
||||
# *Note*: To match whitespace in an <tt>x</tt> pattern use an escape such as
|
||||
# <tt>\s</tt> or <tt>\p{Space}</tt>.
|
||||
#
|
||||
# Comments can be included in a non-<tt>x</tt> pattern with the
|
||||
# <tt>(?#</tt><i>comment</i><tt>)</tt> construct, where <i>comment</i> is
|
||||
# arbitrary text ignored by the regexp engine.
|
||||
#
|
||||
# == Encoding
|
||||
#
|
||||
# Regular expressions are assumed to use the source encoding. This can be
|
||||
# overridden with one of the following modifiers.
|
||||
#
|
||||
# * <tt>/</tt><i>pat</i><tt>/u</tt> - UTF-8
|
||||
# * <tt>/</tt><i>pat</i><tt>/e</tt> - EUC-JP
|
||||
# * <tt>/</tt><i>pat</i><tt>/s</tt> - Windows-31J
|
||||
# * <tt>/</tt><i>pat</i><tt>/n</tt> - ASCII-8BIT
|
||||
#
|
||||
# A regexp can be matched against a string when they either share an
|
||||
# encoding, or the regexp's encoding is _US-ASCII_ and the string's encoding
|
||||
# is ASCII-compatible.
|
||||
#
|
||||
# If a match between incompatible encodings is attempted an
|
||||
# <tt>Encoding::CompatibilityError</tt> exception is raised.
|
||||
#
|
||||
# The <tt>Regexp#fixed_encoding?</tt> predicate indicates whether the regexp
|
||||
# has a <i>fixed</i> encoding, that is one incompatible with ASCII. A
|
||||
# regexp's encoding can be explicitly fixed by supplying
|
||||
# <tt>Regexp::FIXEDENCODING</tt> as the second argument of
|
||||
# <tt>Regexp.new</tt>:
|
||||
#
|
||||
# r = Regexp.new("a".force_encoding("iso-8859-1"),Regexp::FIXEDENCODING)
|
||||
# r =~"a\u3042"
|
||||
# #=> Encoding::CompatibilityError: incompatible encoding regexp match
|
||||
# (ISO-8859-1 regexp with UTF-8 string)
|
||||
#
|
||||
# == Performance
|
||||
#
|
||||
# Certain pathological combinations of constructs can lead to abysmally bad
|
||||
# performance.
|
||||
#
|
||||
# Consider a string of 25 <i>a</i>s, a <i>d</i>, 4 <i>a</i>s, and a
|
||||
# <i>c</i>.
|
||||
#
|
||||
# s = 'a' * 25 + 'd' 'a' * 4 + 'c'
|
||||
# #=> "aaaaaaaaaaaaaaaaaaaaaaaaadadadadac"
|
||||
#
|
||||
# The following patterns match instantly as you would expect:
|
||||
#
|
||||
# /(b|a)/ =~ s #=> 0
|
||||
# /(b|a+)/ =~ s #=> 0
|
||||
# /(b|a+)*\/ =~ s #=> 0
|
||||
#
|
||||
# However, the following pattern takes appreciably longer:
|
||||
#
|
||||
# /(b|a+)*c/ =~ s #=> 32
|
||||
#
|
||||
# This happens because an atom in the regexp is quantified by both an
|
||||
# immediate <tt>+</tt> and an enclosing <tt>*</tt> with nothing to
|
||||
# differentiate which is in control of any particular character. The
|
||||
# nondeterminism that results produces super-linear performance. (Consult
|
||||
# <i>Mastering Regular Expressions</i> (3rd ed.), pp 222, by
|
||||
# <i>Jeffery Friedl</i>, for an in-depth analysis). This particular case
|
||||
# can be fixed by use of atomic grouping, which prevents the unnecessary
|
||||
# backtracking:
|
||||
#
|
||||
# (start = Time.now) && /(b|a+)*c/ =~ s && (Time.now - start)
|
||||
# #=> 24.702736882
|
||||
# (start = Time.now) && /(?>b|a+)*c/ =~ s && (Time.now - start)
|
||||
# #=> 0.000166571
|
||||
#
|
||||
# A similar case is typified by the following example, which takes
|
||||
# approximately 60 seconds to execute for me:
|
||||
#
|
||||
# # Match a string of 29 <i>a</i>s against a pattern of 29 optional
|
||||
# # <i>a</i>s followed by 29 mandatory <i>a</i>s.
|
||||
# Regexp.new('a?' * 29 + 'a' * 29) =~ 'a' * 29
|
||||
#
|
||||
# The 29 optional <i>a</i>s match the string, but this prevents the 29
|
||||
# mandatory <i>a</i>s that follow from matching. Ruby must then backtrack
|
||||
# repeatedly so as to satisfy as many of the optional matches as it can
|
||||
# while still matching the mandatory 29. It is plain to us that none of the
|
||||
# optional matches can succeed, but this fact unfortunately eludes Ruby.
|
||||
#
|
||||
# One approach for improving performance is to anchor the match to the
|
||||
# beginning of the string, thus significantly reducing the amount of
|
||||
# backtracking needed.
|
||||
#
|
||||
# Regexp.new('\A' 'a?' * 29 + 'a' * 29).match('a' * 29)
|
||||
# #=> #<MatchData "aaaaaaaaaaaaaaaaaaaaaaaaaaaaa">
|
||||
#
|
||||
#
|
||||
class Regexp; end
|
||||
end
|
||||
3
re.c
3
re.c
|
|
@ -3433,6 +3433,9 @@ re_warn(const char *s)
|
|||
* <code>%r{...}</code> literals, and by the <code>Regexp::new</code>
|
||||
* constructor.
|
||||
*
|
||||
* A comprehensive reference for regexp syntax and usage is available as
|
||||
* +Doc::Regexp+.
|
||||
*
|
||||
*/
|
||||
|
||||
void
|
||||
|
|
|
|||
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