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match_data.cr
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match_data.cr
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class Regex
# `Regex::MatchData` is the type of the special variable `$~`, and is the type
# returned by `Regex#match` and `String#match`. It encapsulates all the
# results of a regular expression match.
#
# ```
# if md = "Crystal".match(/[p-s]/)
# md.string # => "Crystal"
# md[0] # => "r"
# md[1]? # => nil
# end
# ```
#
# Many `Regex::MatchData` methods deal with capture groups, and accept an integer
# argument to select the desired capture group. Capture groups are numbered
# starting from `1`, so that `0` can be used to refer to the entire regular
# expression without needing to capture it explicitly.
struct MatchData
# Returns the original regular expression.
#
# ```
# "Crystal".match(/[p-s]/).not_nil!.regex # => /[p-s]/
# ```
getter regex : Regex
# Returns the number of capture groups, including named capture groups.
#
# ```
# "Crystal".match(/[p-s]/).not_nil!.group_size # => 0
# "Crystal".match(/r(ys)/).not_nil!.group_size # => 1
# "Crystal".match(/r(ys)(?<ok>ta)/).not_nil!.group_size # => 2
# ```
getter group_size : Int32
# Returns the original string.
#
# ```
# "Crystal".match(/[p-s]/).not_nil!.string # => "Crystal"
# ```
getter string : String
# :nodoc:
def initialize(@regex : Regex, @code : LibPCRE::Pcre, @string : String, @pos : Int32, @ovector : Int32*, @group_size : Int32)
end
# Returns the number of elements in this match object.
#
# ```
# "Crystal".match(/[p-s]/).not_nil!.size # => 1
# "Crystal".match(/r(ys)/).not_nil!.size # => 2
# "Crystal".match(/r(ys)(?<ok>ta)/).not_nil!.size # => 3
# ```
def size
group_size + 1
end
# Returns the position of the first character of the *n*th match.
#
# When *n* is `0` or not given, uses the match of the entire `Regex`.
# Otherwise, uses the match of the *n*th capture group.
#
# ```
# "Crystal".match(/r/).not_nil!.begin(0) # => 1
# "Crystal".match(/r(ys)/).not_nil!.begin(1) # => 2
# "クリスタル".match(/リ(ス)/).not_nil!.begin(0) # => 1
# ```
def begin(n = 0)
@string.byte_index_to_char_index byte_begin(n)
end
# Returns the position of the next character after the match.
#
# When *n* is `0` or not given, uses the match of the entire `Regex`.
# Otherwise, uses the match of the *n*th capture group.
#
# ```
# "Crystal".match(/r/).not_nil!.end(0) # => 2
# "Crystal".match(/r(ys)/).not_nil!.end(1) # => 4
# "クリスタル".match(/リ(ス)/).not_nil!.end(0) # => 3
# ```
def end(n = 0)
@string.byte_index_to_char_index byte_end(n)
end
# Returns the position of the first byte of the *n*th match.
#
# When *n* is `0` or not given, uses the match of the entire `Regex`.
# Otherwise, uses the match of the *n*th capture group.
#
# ```
# "Crystal".match(/r/).not_nil!.byte_begin(0) # => 1
# "Crystal".match(/r(ys)/).not_nil!.byte_begin(1) # => 2
# "クリスタル".match(/リ(ス)/).not_nil!.byte_begin(0) # => 3
# ```
def byte_begin(n = 0)
check_index_out_of_bounds n
n += size if n < 0
@ovector[n * 2]
end
# Returns the position of the next byte after the match.
#
# When *n* is `0` or not given, uses the match of the entire `Regex`.
# Otherwise, uses the match of the *n*th capture group.
#
# ```
# "Crystal".match(/r/).not_nil!.byte_end(0) # => 2
# "Crystal".match(/r(ys)/).not_nil!.byte_end(1) # => 4
# "クリスタル".match(/リ(ス)/).not_nil!.byte_end(0) # => 9
# ```
def byte_end(n = 0)
check_index_out_of_bounds n
n += size if n < 0
@ovector[n * 2 + 1]
end
# Returns the match of the *n*th capture group, or `nil` if there isn't
# an *n*th capture group.
#
# When *n* is `0`, returns the match for the entire `Regex`.
#
# ```
# "Crystal".match(/r(ys)/).not_nil![0]? # => "rys"
# "Crystal".match(/r(ys)/).not_nil![1]? # => "ys"
# "Crystal".match(/r(ys)/).not_nil![2]? # => nil
# ```
def []?(n : Int)
return unless valid_group?(n)
n += size if n < 0
start = @ovector[n * 2]
finish = @ovector[n * 2 + 1]
return if start < 0
@string.byte_slice(start, finish - start)
end
# Returns the match of the *n*th capture group, or raises an `IndexError`
# if there is no *n*th capture group.
#
# ```
# "Crystal".match(/r(ys)/).not_nil![1] # => "ys"
# "Crystal".match(/r(ys)/).not_nil![2] # raises IndexError
# ```
def [](n : Int)
check_index_out_of_bounds n
n += size if n < 0
value = self[n]?
raise_capture_group_was_not_matched n if value.nil?
value
end
# Returns the match of the capture group named by *group_name*, or
# `nil` if there is no such named capture group.
#
# ```
# "Crystal".match(/r(?<ok>ys)/).not_nil!["ok"]? # => "ys"
# "Crystal".match(/r(?<ok>ys)/).not_nil!["ng"]? # => nil
# ```
#
# When there are capture groups having same name, it returns the last
# matched capture group.
#
# ```
# "Crystal".match(/(?<ok>Cr).*(?<ok>al)/).not_nil!["ok"]? # => "al"
# ```
def []?(group_name : String)
max_start = -1
match = nil
named_capture_number(group_name) do |n|
start = @ovector[n * 2]
if start > max_start
max_start = start
match = self[n]?
end
end
match
end
# Returns the match of the capture group named by *group_name*, or
# raises an `KeyError` if there is no such named capture group.
#
# ```
# "Crystal".match(/r(?<ok>ys)/).not_nil!["ok"] # => "ys"
# "Crystal".match(/r(?<ok>ys)/).not_nil!["ng"] # raises KeyError
# ```
#
# When there are capture groups having same name, it returns the last
# matched capture group.
#
# ```
# "Crystal".match(/(?<ok>Cr).*(?<ok>al)/).not_nil!["ok"] # => "al"
# ```
def [](group_name : String)
match = self[group_name]?
unless match
named_capture_number(group_name) do
raise KeyError.new("Capture group '#{group_name}' was not matched")
end
raise KeyError.new("Capture group '#{group_name}' does not exist")
end
match
end
# Returns all matches that are within the given range.
def [](range : Range)
self[*Indexable.range_to_index_and_count(range, size) || raise IndexError.new]
end
# Like `#[Range]`, but returns `nil` if the range's start is out of range.
def []?(range : Range)
self[*Indexable.range_to_index_and_count(range, size) || raise IndexError.new]?
end
# Returns count or less (if there aren't enough) matches starting at the
# given start index.
def [](start : Int, count : Int)
self[start, count]? || raise IndexError.new
end
# Like `#[Int, Int]` but returns `nil` if the *start* index is out of range.
def []?(start : Int, count : Int)
raise ArgumentError.new "Negative count: #{count}" if count < 0
return Array(String).new if start == size
start += size if start < 0
if 0 <= start <= size
return Array(String).new if count == 0
count = Math.min(count, size - start)
Array(String).new(count) { |i| self[start + i] }
end
end
private def named_capture_number(group_name)
name_entry_size = LibPCRE.get_stringtable_entries(@code, group_name, out first, out last)
return if name_entry_size < 0
while first <= last
capture_number = (first[0].to_u16 << 8) | first[1].to_u16
yield capture_number
first += name_entry_size
end
nil
end
# Returns the part of the original string before the match. If the match
# starts at the start of the string, returns the empty string.
#
# ```
# "Crystal".match(/yst/).not_nil!.pre_match # => "Cr"
# ```
def pre_match
@string.byte_slice(0, byte_begin(0))
end
# Returns the part of the original string after the match. If the match ends
# at the end of the string, returns the empty string.
#
# ```
# "Crystal".match(/yst/).not_nil!.post_match # => "al"
# ```
def post_match
@string.byte_slice(byte_end(0))
end
# Returns an array of unnamed capture groups.
#
# It is a difference from `to_a` that the result array does not contain the match for the entire `Regex` (`self[0]`).
#
# ```
# match = "Crystal".match(/(Cr)(?<name1>y)(st)(?<name2>al)/).not_nil!
# match.captures # => ["Cr", "st"]
#
# # When this regex has an optional group, result array may contain
# # a `nil` if this group is not matched.
# match = "Crystal".match(/(Cr)(stal)?/).not_nil!
# match.captures # => ["Cr", nil]
# ```
def captures
name_table = @regex.name_table
caps = [] of String?
(1...size).each do |i|
caps << self[i]? unless name_table.has_key? i
end
caps
end
# Returns a hash of named capture groups.
#
# ```
# match = "Crystal".match(/(Cr)(?<name1>y)(st)(?<name2>al)/).not_nil!
# match.named_captures # => {"name1" => "y", "name2" => "al"}
#
# # When this regex has an optional group, result hash may contain
# # a `nil` if this group is not matched.
# match = "Crystal".match(/(?<name1>Cr)(?<name2>stal)?/).not_nil!
# match.named_captures # => {"name1" => "Cr", "name2" => nil}
# ```
def named_captures
name_table = @regex.name_table
caps = {} of String => String?
(1...size).each do |i|
if (name = name_table[i]?) && !caps.has_key?(name)
caps[name] = self[name]?
end
end
caps
end
# Convert this match data into an array.
#
# ```
# match = "Crystal".match(/(Cr)(?<name1>y)(st)(?<name2>al)/).not_nil!
# match.to_a # => ["Crystal", "Cr", "y", "st", "al"]
#
# # When this regex has an optional group, result array may contain
# # a `nil` if this group is not matched.
# match = "Crystal".match(/(Cr)(?<name1>stal)?/).not_nil!
# match.to_a # => ["Cr", "Cr", nil]
# ```
def to_a
(0...size).map { |i| self[i]? }
end
# Convert this match data into a hash.
#
# ```
# match = "Crystal".match(/(Cr)(?<name1>y)(st)(?<name2>al)/).not_nil!
# match.to_h # => {0 => "Crystal", 1 => "Cr", "name1" => "y", 3 => "st", "name2" => "al"}
#
# # When this regex has an optional group, result array may contain
# # a `nil` if this group is not matched.
# match = "Crystal".match(/(Cr)(?<name1>stal)?/).not_nil!
# match.to_h # => {0 => "Cr", 1 => "Cr", "name1" => nil}
# ```
def to_h
name_table = @regex.name_table
hash = {} of (String | Int32) => String?
(0...size).each do |i|
if name = name_table[i]?
hash[name] = self[name]? unless hash.has_key?(name)
else
hash[i] = self[i]?
end
end
hash
end
def inspect(io : IO) : Nil
to_s(io)
end
def to_s(io : IO) : Nil
name_table = @regex.name_table
io << "Regex::MatchData("
size.times do |i|
io << ' ' << name_table.fetch(i, i) << ':' if i > 0
self[i]?.inspect(io)
end
io << ')'
end
def pretty_print(pp) : Nil
name_table = @regex.name_table
pp.surround("Regex::MatchData(", ")", left_break: nil, right_break: nil) do
size.times do |i|
pp.breakable if i > 0
pp.group do
if i == 0
self[i].pretty_print pp
else
pp.text "#{name_table.fetch(i, i)}:"
pp.nest do
pp.breakable ""
self[i]?.pretty_print pp
end
end
end
end
end
end
def dup
self
end
def clone
self
end
def ==(other : Regex::MatchData)
return false unless size == other.size
return false unless regex == other.regex
return false unless string == other.string
return @ovector.memcmp(other.@ovector, size * 2) == 0
end
# See `Object#hash(hasher)`
def hash(hasher)
hasher = regex.hash hasher
hasher = string.hash hasher
Slice.new(@ovector, size * 2).hash(hasher)
end
private def check_index_out_of_bounds(index)
raise_invalid_group_index(index) unless valid_group?(index)
end
private def valid_group?(index)
-size <= index < size
end
private def raise_invalid_group_index(index)
raise IndexError.new("Invalid capture group index: #{index}")
end
private def raise_capture_group_was_not_matched(index)
raise IndexError.new("Capture group #{index} was not matched")
end
end
end