ruby--ruby/NEWS

# -*- rdoc -*-

= NEWS for Ruby 2.2.0

This document is a list of user visible feature changes made between
releases except for bug fixes.

Note that each entry is kept so brief that no reason behind or
reference information is supplied with.  For a full list of changes
with all sufficient information, see the ChangeLog file.

== Changes since the 2.1.0 release

=== Language changes

=== Core classes updates (outstanding ones only)

* Enumerable
  * Extended methods:
    * min, min_by, max and max_by supports optional argument to return
      multiple elements.

* Symbol
  * New methods
    * Symbol.find(str) returns whether given string is defined as symbol or not.
  * Improvements
    * Most symbols which are returned by String#to_sym and
      String#intern are GC-able.

* Matrix
  * New methods:
    * Matrix#first_minor(row, column) returns the submatrix obtained
      by deleting the specified row and column.
    * Matrix#cofactor(row, column) returns the (row, column) cofactor
      which is obtained by multiplying the first minor by (-1)**(row + column).

=== Core classes compatibility issues (excluding feature bug fixes)

* IO
  * incompatible changes:
    * When flushing file IO, you cannot assume that the metadata of the file
      is updated immediately.  On some platforms (especially Windows), it is
      delayed until the filesystem load is decreased.
* Proc
  * incompatible changes:
    * ArgumentError is no longer raised when lambda Proc is passed as a
      block, and the number of yielded arguments does not match the formal
      arguments of the lambda, if just an array is yielded and its length
      matches.

=== Stdlib updates (outstanding ones only)

* Find, Pathname
  * Extended methods:
    * find method accepts "ignore_error" keyword argument.

=== Stdlib compatibility issues (excluding feature bug fixes)

=== Built-in global variables compatibility issues

=== C API updates

* Deprecated APIs removed.  [Feature #9502]

  Check_SafeStr -> SafeStringValue
  rb_check_safe_str -> SafeStringValue
  rb_quad_pack -> rb_integer_pack
  rb_quad_unpack -> rb_integer_unpack
  rb_read_check : access struct FILE internal. no replacement.
  rb_struct_iv_get : internal function. no replacement.
  struct rb_blocking_region_buffer : internal type. no replacement.
  rb_thread_blocking_region_begin -> rb_thread_call_without_gvl family
  rb_thread_blocking_region_end -> rb_thread_call_without_gvl family
  TRAP_BEG -> rb_thread_call_without_gvl family
  TRAP_END -> rb_thread_call_without_gvl family
  rb_thread_select -> rb_thread_fd_select
  struct rb_exec_arg : internal type. no replacement.
  rb_exec : internal function. no replacement.
  rb_exec_arg_addopt : internal function. no replacement.
  rb_exec_arg_fixup : internal function. no replacement.
  rb_exec_arg_init : internal function. no replacement.
  rb_exec_err : internal function. no replacement.
  rb_fork : internal function. no replacement.
  rb_fork_err : internal function. no replacement.
  rb_proc_exec_n : internal function. no replacement.
  rb_run_exec_options : internal function. no replacement.
  rb_run_exec_options_err : internal function. no replacement.
  rb_thread_blocking_region -> rb_thread_call_without_gvl family
  rb_thread_polling -> rb_thread_wait_for
  rb_big2str0 : internal function. no replacement.
  rb_big2ulong_pack -> rb_integer_pack
  rb_gc_set_params : internal function. no replacement.

* struct RBignum is hidden.  [Feature #6083]
  Use rb_integer_pack and rb_integer_unpack instead.

* st hash table uses power-of-two sizes for speed [Feature #9425].
  Lookups are 10-25% faster if using appropriate hash functions.
  However, weaknesses in hash distribution can no longer be masked
  by prime number-sized tables, so extensions may need to tweak
  hash functions to ensure good distribution.

* rb_sym2str() added. This is almost same as `rb_id2str(SYM2ID(sym))`
  but not pinning a dynamic symbol.

* struct RSymbol added. This represents a dynamic symbol as object in
  Ruby's heaps.

* rb_str_cat_cstr() added. This is same as `rb_str_cat2()`.

* `rb_str_substr()` and `rb_str_subseq()` now share middle of a string,
  but not only the end of a string.  Therefore, result strings may not
  be NULL-terminated, `StringValueCStr()` is needed calling to obtain a
  NULL-terminated C string.