struct Char::Reader
Overview
A Char::Reader allows iterating a String by Chars.
As soon as you instantiate a Char::Reader it will decode the first
char in the String, which can be accessed by invoking #current_char
.
At this point #pos
, the current position in the string, will equal zero.
Successive calls to #next_char
return the next chars in the string,
advancing #pos
.
Note that the null character '\0' will be returned in #current_char
when
the end is reached (as well as when the string is empty). Thus, #has_next?
will return false
only when #pos
is equal to the string's bytesize, in which
case #current_char
will always be '\0'.
Included Modules
Defined in:
char/reader.crClass Method Summary
-
.new(string : String)
Creates a reader with the specified string
Instance Method Summary
-
#current_char : Char
Returns the current character.
-
#current_char_width : Int32
Returns the size of the current_char (in bytes) as if it were encoded in UTF-8.
- #each(&block)
-
#has_next?
Returns true if there is a character left to read.
-
#next_char
Reads the next character in the string,
#pos
is incremented. - #peek_next_char
-
#pos : Int32
Returns the position of the current character.
-
#pos=(pos)
Sets
#pos
to pos. -
#string : String
Returns the reader's String.
Instance methods inherited from module Enumerable({"T", T})
all?all?(&block) all?, any?
any?(&block) any?, compact_map(&block) compact_map, count(item)
count(&block) count, cycle(&block)
cycle(n, &block) cycle, each(&block : T -> _) each, each_cons(count : Int, &block) each_cons, each_slice(count : Int, &block) each_slice, each_with_index(offset = 0, &block) each_with_index, each_with_object(obj, &block) each_with_object, find(if_none = nil, &block) find, first
first(count : Int) first, first? first?, flat_map(&block : T -> Array(U)) forall U flat_map, grep(pattern) grep, group_by(&block : T -> U) forall U group_by, in_groups_of(size : Int, filled_up_with : U = nil, &block) forall U
in_groups_of(size : Int, filled_up_with : U = nil) forall U in_groups_of, includes?(obj) includes?, index(obj)
index(&block) index, index_by(&block : T -> U) forall U index_by, join(separator = "")
join(separator, io, &block)
join(separator = "", &block)
join(separator, io) join, map(&block : T -> U) forall U map, map_with_index(&block : T, Int32 -> U) map_with_index, max max, max? max?, max_by(&block : T -> U) forall U max_by, max_by?(&block : T -> U) forall U max_by?, max_of(&block : T -> U) forall U max_of, max_of?(&block : T -> U) forall U max_of?, min min, min? min?, min_by(&block : T -> U) forall U min_by, min_by?(&block : T -> U) forall U min_by?, min_of(&block : T -> U) forall U min_of, min_of?(&block : T -> U) forall U min_of?, minmax minmax, minmax? minmax?, minmax_by(&block : T -> U) forall U minmax_by, minmax_by?(&block : T -> U) forall U minmax_by?, minmax_of(&block : T -> U) forall U minmax_of, minmax_of?(&block : T -> U) forall U minmax_of?, none?(&block)
none? none?, one?(&block) one?, partition(&block) partition, product(initial : Number, &block)
product
product(initial : Number)
product(&block) product, reduce(memo, &block)
reduce(&block) reduce, reject(&block : T -> ) reject, select(&block : T -> ) select, size size, skip(count : Int) skip, skip_while(&block) skip_while, sum
sum(initial)
sum(&block)
sum(initial, &block) sum, take_while(&block) take_while, to_a to_a, to_h to_h, to_set to_set
Instance methods inherited from struct Struct
==(other : self) : Bool
==,
hash : Int32
hash,
inspect(io : IO) : Nil
inspect,
to_s(io)
to_s
Instance methods inherited from struct Value
==(other)
==,
dup
dup
Instance methods inherited from class Object
!=(other)
!=,
!~(other)
!~,
==(other)
==,
===(other)===(other : YAML::Any)
===(other : JSON::Any) ===, =~(other) =~, class class, crystal_type_id crystal_type_id, dup dup, hash hash, inspect(io : IO)
inspect inspect, itself itself, not_nil! not_nil!, tap(&block) tap, to_json to_json, to_pretty_json(indent : String = " ")
to_pretty_json(io : IO, indent : String = " ") to_pretty_json, to_s
to_s(io : IO) to_s, to_yaml
to_yaml(io : IO) to_yaml, try(&block) try
Class methods inherited from class Object
==(other : Class)
==,
===(other)
===,
cast(other) : self
cast,
clone
clone,
dup
dup,
from_json(string_or_io) : selffrom_json(string_or_io, root : String) : self from_json, from_yaml(string : String) : self from_yaml, hash hash, inspect(io) inspect, name : String name, nilable? nilable?, to_s(io) to_s, |(other : U.class) forall U |
Class Method Detail
Instance Method Detail
Returns the current character.
reader = Char::Reader.new("ab")
reader.current_char # => 'a'
reader.next_char
reader.current_char # => 'b'
Returns the size of the current_char (in bytes) as if it were encoded in UTF-8.
reader = Char::Reader.new("aƩ")
reader.current_char_width # => 1
reader.next_char
reader.current_char_width # => 2
Yields successive characters from #string
starting from #pos
.
reader = Char::Reader.new("abc")
reader.next_char
reader.each do |c|
puts c.upcase
end
B
C
Returns true if there is a character left to read. The terminating byte '\0' is considered a valid character by this method.
reader = Char::Reader.new("a")
reader.has_next? # => true
reader.peek_next_char # => '\0'
Reads the next character in the string,
#pos
is incremented. Raises IndexError
if the reader is
at the end of the #string
reader = Char::Reader.new("ab")
reader.next_char # => 'b'
Returns the next character in the #string
without incrementing #pos
.
Raises IndexError
if the reader is at
the end of the #string
reader = Char::Reader.new("ab")
reader.peek_next_char # => 'b'
reader.current_char # => 'a'
Returns the position of the current character.
reader = Char::Reader.new("ab")
reader.pos # => 0
reader.next_char
reader.pos # => 1