Significant changes to the "ore" package are laid out below for each release.

===============================================================================

VERSION 1.8.0

- The bundled Onigmo regular expression library has been brought up to date
  with fixes made since version 6.2.0, both upstream and in the copy maintained
  as part of Ruby. These address a number of crashes, memory errors and
  incorrect results, particularly with unusual or malformed regexes.
- Unicode data has been updated from version 9.0 to version 17.0, so character
  properties (`\p{...}`) and case-insensitive matching now cover recent
  additions such as additional scripts and emoji. The `\X` (extended grapheme
  cluster) escape, which previously crashed R when used with UTF-8 text, now
  works and follows current Unicode segmentation rules.
- A group that matches an empty string is now returned as an empty string,
  rather than `NA`. Groups that don't take part in a match are still `NA`, and
  their offsets and lengths are now `NA` too.
- When several replacement strings are given to `ore_subst()`, they are now
  applied to successive matches, as documented. Previously the last one used
  was applied to all matches, unless the replacements contained
  back-references.
- Strings with no declared encoding (such as those read by `readLines()`
  without its `encoding` argument) are now matched in the encoding given by the
  `ore.encoding` option when the regex is given as a string, rather than being
  treated as ASCII. Previously, for example, `\w` would not match accented
  letters in such strings.
- Encoding names are now matched in full, and in a case-insensitive and
  separator-insensitive way, so names such as "ISO-8859-15" are now handled
  correctly rather than being treated as ISO-8859-1 (due to a partial match).
  The "LATINn" aliases now refer to the standard encodings, and unrecognised
  names give a warning.
- Text read from files or connections in encodings other than ASCII, UTF-8 or
  Latin-1 (e.g., Shift-JIS) is now converted to UTF-8 when returned to R.
- Searching files in UTF-16 or UTF-32 now works.
- Results from UTF-8 text are no longer corrupted when the session locale uses
  a different encoding.
- Vectors mixing UTF-8 and Latin-1 strings are now searched fully when the
  regex is given as a string, rather than elements in the "other" encoding
  being skipped with a warning.
- Regexes created with `ore()` and then saved (e.g., with `saveRDS()`) and
  loaded again now keep their options and syntax.
- Starting positions passed to the main functions must now be positive
  integers; zero, negative and `NA` values produce an error rather than being
  quietly treated as giving no match. Starting positions beyond the end of the
  text, which crashed R with multibyte encodings, now consistently give no
  match.
- Calling `ore()` with a missing (`NA`) pattern is now an error, and
  unsupported letters in its `options` argument produce a warning rather than
  being ignored.
- `ore_repl()` now passes the correct matched text to replacement functions
  when there are several matches and the regex contains groups, and no longer
  fails when there are several groups and several matches.
- Back-references to groups that don't take part in a match, or match an empty
  string, previously crashed R. They are now replaced with nothing.
- The `\G` anchor could match when it shouldn't, because a failed search was
  retried from later in the text. Failed searches are no longer repeated, which
  also makes searches faster when many strings don't match.
- Character offsets of repeated empty matches were wrong in multibyte
  encodings. This has been corrected.
- Searching large numbers of strings, with `ore_search()` or `%~%`, is now
  substantially faster, due to more efficient memory use.
- Printed matches now use display widths based on current Unicode data, so
  emoji, wide characters and newer combining marks line up correctly. Text is
  converted to the session's encoding for display, with characters that can't
  be shown replaced by "?", and carriage returns are shown as "\r". A crash
  when printing text containing many zero-width characters has been fixed.
- `es()` now only removes the escape from "\\#{", leaving other backslashes
  intact.
- Connections opened by the package in order to search them are now closed
  again afterwards. Connections that were already open are left open.
- `ore_escape()` now preserves the declared encoding of its argument.
- The native encoding is now detected more reliably when the package is loaded,
  using R's own locale information where possible. In a Latin-1 locale the
  `ore.encoding` option is now set to "latin1", and the C locale is treated as
  ASCII without a startup message.

===============================================================================

VERSION 1.7.5

- There is now special handling of repeated zero-length matches to avoid
  infinite loops. Specifically, a zero-length match is no longer allowed at the
  same offset in the string as the last zero-length match; if there is no
  non-empty match available, the starting offset is first advanced by one
  character.

===============================================================================

VERSION 1.7.4

- Named groups would not be propagated to match matrices unless the regex was
  pre-compiled using `ore()`. This has been corrected.
- A compiler warning about a `printf`-type format specification has been
  resolved.

===============================================================================

VERSION 1.7.3

- The package will now properly detect a plain locale like "UTF-8" on start-up.
- C prototype warnings have been resolved, and the problematic `sprintf()`
  function is now avoided.

===============================================================================

VERSION 1.7.2

- A handful of small memory leaks have been plugged.
- The `README` has been updated to detail the current divergence between CRAN
  and mainline versions of the package.

===============================================================================

VERSION 1.7.1

- The `binary` argument to `ore_file()` is now stored in an attribute in its
  return value. The `ore_search()` function additionally uses this attribute
  to determine whether or not to set the `text` element of its return value.
  Treating a binary file's entire contents as a string is unwise, and may
  include embedded nuls and other problem bytes.
- A minor tweak has been made to the `es()` function, which appreciably
  improves its performance in simple cases.
- A potential buffer overrun and protection bug have both been corrected.

===============================================================================

VERSION 1.7.0

- The Onigmo library has been updated to version 6.2.0.
- R connections are now supported as text sources, allowing URLs, gzipped files
  and pipes (amongst others; see `?connections`) to be straightforwardly
  interfaced with the package. The package's C backend has been substantially
  refactored to support files and connections in all the core functions.
- The new `ore_switch()` function selects between a number of possible outputs
  by matching each element of its input against a series of regular
  expressions. This can be a useful way to handle different possible forms of
  the same information.
- The new `ore_repl()` function is a relative of the existing `ore_subst()`,
  but differs in how it is vectorised. Unlike `ore_subst()`, it will replicate
  the source text if necessary to ensure that all specified replacements are
  used. The `es()` function now uses `ore_repl()`, and so can produce output
  vectors longer than its input.
- `ore_subst()` gains a "start" argument, like `ore_search()`, and now accepts
  multiple replacements, which will be applied in sequence to different
  matches.
- `ore_match()` is a new alias of `ore_search()`.
- Substitution group references can now include "\\0" for the whole match
  string, and allow for group numbers higher than 9. Group numbers that are out
  of range should now produce an error, rather than potentially leading to a
  segfault. Named group references should also be more robust.
- A multilingual, multiscript dataset, "glass", is now included with the
  package thanks to Frank da Cruz and many contributors.
- Names and `NA` values are now propagated from text arguments that are
  character vectors.
- There is a new option (`ore.keepNA`) to propagate `NA`s in `ore_ismatch()`,
  and the infix functions `%~%` and `%~~%`, rather than convert them
  implicitly to `FALSE`. This is off by default for backwards compatibility.
- Printing has been improved, and in particular "orematches" objects now show
  (just) the elements that matched.
- Underscore-separated names are now used in preference in the package
  documentation, following the trend in other packages, but the period-
  separated versions are still available.
- Detection of the platform's native encoding has been improved, and this will
  be asserted in regular expressions created by `ore()`, rather than them being
  marked as being in "unknown" encoding by default as before. Handling of
  encodings has been refined elsewhere too.

===============================================================================

VERSION 1.6.3

- The ore.file() function now performs path expansion on its argument.
- The package is now more careful to check that "external" pointers are valid
  before dereferencing them, thereby avoiding potential segfaults. (Reported
  by Thomas Weise, #5).
- Multiarchitecture support is now explicitly declared, ensuring that 32-bit
  and 64-bit versions are built when installing from source on Windows.
  (Reported by Ioannis Mamalikidis, #6).

===============================================================================

VERSION 1.6.2

- Additional warnings from GCC 8 and rchk have been resolved.

===============================================================================

VERSION 1.6.1

- The Onigmo library has been updated to version 6.1.3.
- Various compiler and sanitiser warnings have been resolved.

===============================================================================

VERSION 1.6.0

- The Onigmo library has been updated to version 6.1.1.
- Files will now be searched incrementally, meaning that large files do not
  need to be read in their entirety if the match is near the beginning. This is
  disabled by default if all matches are requested.
- Additional arguments to ore.search() are now accessible through an ellipsis
  argument to ore.ismatch().
- The results of a substitution function are now recycled across matches, and
  can therefore be of any length. 
- A handful of subtle garbage-collection heisenbugs have been corrected.
  (Reported by Tomas Kalibera.)

===============================================================================

VERSION 1.5.0

- The object returned by ore.search() now generally has the class "orematches".
  This class has its own indexing and print methods to avoid copious output and
  allow quicker access to multiple matches.
- The ore.search() and ore.split() functions now accept zero-length text
  vectors, returning an empty list rather than producing an error.
- The matches() and groups() functions now use the last match by default, if
  called with no argument.

===============================================================================

VERSION 1.4.0

- The new ore.escape() function can be used to escape characters which would
  usually have special significance in a regular expression. This can be
  helpful when incorporating arbitrary strings into a regex using ore().

===============================================================================

VERSION 1.3.0

- It is now possible to search directly in text files, using their native
  encoding, or in binary files, byte-by-byte. To do this, a call to the new
  ore.file() function should replace the usual text argument to ore.search().
  All of Onigmo's many encodings are supported for text files.
- A new infix operator, %~|%, can be used filter vectors by whether they match
  a regular expression.
- The "matches" and "groups" methods for lists now drop nonmatching elements by
  default. This helps avoid many NULLs in results.
- The "print" method for "orematch" objects now works correctly with
  double-width characters.

===============================================================================

VERSION 1.2.2

- Zero-length matches could lead to segmentation faults. This has been
  corrected.
- Calls to ore.dict() which include other function calls are now handled
  properly. (Reported by Jon Olav Vik.)
- The es() function would previously only honour its rounding arguments if all
  matches were numeric. This has been corrected.

===============================================================================

VERSION 1.2.1

- The es() function would previously only replace the first embedded
  expression. That has been corrected.
- Attributes are now ignored when comparing "ore" objects in tests. This led to
  a failure on versions of R prior to 3.2.0, at least on Windows.

===============================================================================

VERSION 1.2.0

- Oniguruma's support for alternative regular expression syntaxes is now
  exposed by the ore() function. At present only "fixed" (i.e., literal)
  patterns are supported in addition to the default, which has always been
  "ruby".
- The ore.lastmatch() function gains a "simplify" argument.
- Underscore-separated function names are now available as aliases to their
  period-separated equivalents. For example, you can use ore_search() instead
  of ore.search(), if you prefer.
- The use of variables holding patterns could sometimes cause errors in ore().
  This has been corrected.

===============================================================================

VERSION 1.1.0

- The package now provides functionality for creating and working with a
  pattern dictionary, and a few predefined patterns are included. This allows
  common regular expressions to be easily named, stored, and integrated into
  larger expressions later. The key new function is ore.dict().
- The new es() function provides expression substitution, a convenient way to
  embed R expressions within strings, and a good example of the package's
  substitution functions in action.
- Printing of "orematch" objects is now much clearer, particularly for long or
  multiline search texts.
- Group matches are now passed to substitution functions, in an attribute.
- The "ore.colour" (or "ore.color") option can now be used to determine whether
  to print in colour, rather than using the crayon package (although the latter
  is still the default).

===============================================================================

VERSION 1.0.7

- Printing "orematch" objects no longer leads to errors. This was due to a
  mismatch in function names between the C code and the calling R code.

===============================================================================

VERSION 1.0.6

- All of the core functions have now switched to primarily C implementations,
  providing substantial performance gains. Minor changes in the handling of
  text encodings have occurred alongside this.
- The limit of 128 matches per string has been removed, due to more
  sophisticated memory management.
- The arguments to ore.subst() have been reordered slightly, to avoid
  inadvertent partial matching when using a substitution function.

===============================================================================

VERSION 1.0.5

- Calculation of match offsets within the C code have been made much more
  efficient.

===============================================================================

VERSION 1.0.4

- Default methods have been added for matches() and groups(), which return NA.
- The "rex" test is now skipped if that package is not available.
- Various low-level warnings/errors from UBSAN have been addressed.

===============================================================================

VERSION 1.0.3

- Almost all of the work of ore.search() is now done in C code rather than R,
  for performance. In testing, ore is now appreciably faster than base R for
  simple searches, when the regex is precompiled. Optimisation of other
  functions will follow in later releases.
- The package no longer requires any specified minimum version of R (although
  it has not been tested on old releases).

===============================================================================

VERSION 1.0.2

- A bug in the ore.subst() function that could produce low-level errors or
  segmentation faults has been fixed.

===============================================================================

VERSION 1.0.1

- Tests should no longer fail in locales which do not use a UTF-8 encoding.
- Documentation tweaks.

===============================================================================

VERSION 1.0.0

- First public release.

===============================================================================
