After some thinking I decided that this may be not desirable in some
cases, so we should not enable it by default. I've edited documentation
of ‘makeExprParser’ to explain why this doesn't work by default and how
to make it work.
Close#64.
‘makeExprParser’ now generates parser that can handle several
occurrences of the same prefix or postfix operator in a row. This allows
to parse something like C pointers (for example ‘**i’) without resorting
to hacks.
The feature is experimental, I'm not entirely sure it's not
buggy. Upcoming additional tests for ‘Text.Megaparsec.Expr’ will show
whether it behaves correctly in all cases and doesn't have adverse
effects. For now, I've edited existing test to generate data with
repeating prefix negations and postfix factorials. Current code-base
passes the test.
What Parsec used is called “FreeBSD” or “BSD 2 clause”. Addition of the
third clause may require contacting all the authors. To hell with it,
let it be “FreeBSD” (which is anyway better than “BSD-like”), I'm a
hacker, not a lawyer (tm).
This commit clarifies license of the software replacing “BSD3” with more
conventional “BSD 3 clause”.
Another change is addition of the third clause originally missing in
license of Parsec (which is licensed under BSD 2 clause license). The
addition of the third clause in form:
* Neither the names of the copyright holders nor the names of
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
does not violate original BSD 2 clause license effectively making it BSD
3 clause license (which I find preferable).
Close#43.
The method allows to fail with arbitrary collection of
messages. ‘unexpected’ is not defined in terms of ‘failure’. One
consequence of this design decision is that ‘failure’ is now method of
‘MonadParsec’, while ‘unexpected’ is not.
Close#47, close#57.
This commit introduces ‘runParser'’ and ‘runParserT'’ functions that
take and return parser state. This makes it possible to partially parse
input, resume parsing, specify non-standard initial textual position,
etc.
Internal changes involve some refactoring to make ‘Reply’ more
readable and facilitate extraction of complete parser state on failure
as well as success.
The commit adds basic tests for the new functionality as well.
Close#62.
Apart from some refactoring, the following important changes were
introduced:
* ‘ParseError’ is now a monoid.
* Added functions ‘addErrorMessages’ and ‘newErrorMessages’.
Now it's impossible to create ‘SourcePos’ with non-positive line number
or column number. Unfortunately we cannot use ‘Numeric.Natural’ because
we need to support older versions of ‘base’.
Closes#56.
In particular, file name and textual position are represented like this:
filename.hs:5:6:
error message
This format should be more conventional, so various tools will be able
to parse it and provide some support (for example, Emacs can work with
this format).
This patch introduces compatibility to base-4.7.0.x. It was tested
on Win 8.1 x86_64, using GHC 7.8.4. It mainly consists of a bunch
of #if !MIN_VERSION(4,8,0) ... #endif additions and a lower bound
on base in the cabal file as well as a general introduction of the
CPP extension via default-extensions.
It also removes a potential error source in tests/Util.hs, since
the backslash in /=\ can lead to strange quirks on certain systems
(backslash and newline only separated by whitespace).
Other, squashed commits:
- Remove 'recent version of base' from Readme
- Change necessary version of GHC
Closes#38.
Now tab width can be manipulated with via the following functions:
* ‘getTabWidth’
* ‘setTabWidth’
Other auxiliary changes were performed, such as updating of
‘updatePosChar’.
This also corrects a bit obsolete descriptions of some functions.
Closes#36.
We should try to preserve original information where possible. User then
can convert case of parsed string if necessary. Previous implementation
discarded actually parsed string and returned argument of the
function — this can be considered as data loss of a sort.
Closes#35.
Since ‘many’ (and thus ‘some’) are the only combinator that can succeed
consuming input and produce hints at the same time we can conclude that
‘cok'’ continuation in ‘pLabel’ combinator is only called when ‘many’ is
labelled. By correcting label in this case prepending the phrase “rest
of ” to actual label we can greatly improve result error message.
Closes#29.
Now testing function can return ‘Either [Message] a’ so it can construct
full list of error messages. This may be useful in some cases when
tokens are more complex than simple characters.
The single test covers 100 % of the module's code. However it doesn't
check quality of error messages, so we still have room for improvement.
Manual tests show that error messages are good.
