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.
* Removed ‘optionMaybe’ parser, because ‘optional’ from
‘Control.Applicative’ does the same thing.
* Renamed ‘tokenPrim’ → ‘token’, removed old ‘token’, because
‘tokenPrim’ is more general and ‘token’ is little used.
* Fixed bug with ‘notFollowedBy’ always succeeded with parsers that
don't consume input, see #6.
* Hint system introduced that greatly improved quality of error messages
and made code of ‘Text.Megaparsec.Prim’ a lot clearer.
The improvements affected other modules too:
* Some parsers from ‘Text.Megaparsec.Combinators’ now live in
‘Text.Megaparsec.Prim’.
* Hint system improved error messages, so I needed to rewrite test for
‘Text.Megaparsec.Char.eol’, since it's error messages are very
intelligent now and cannot be emulated by ‘newline’ and ‘crlf’ parsers
used separately.
* Test for Bug9 from old-tests is passed successfully again.
Added new character parsers in ‘Text.Megaparsec.Char’:
* ‘controlChar’
* ‘printChar’
* ‘markChar’
* ‘numberChar’
* ‘punctuationChar’
* ‘symbolChar’
* ‘separatorChar’
* ‘asciiChar’
* ‘latin1Char’
* ‘charCategory’
Renamed some parsers:
‘spaces’ → ‘space’
‘space’ → ‘spaceChar’
‘lower’ → ‘lowerChar’
‘upper’ → ‘upperChar’
‘letter’ → ‘letterChar’
‘alphaNum’ → ‘alphaNumChar’
‘digit’ → ‘digitChar’
‘octDigit’ → ‘octDigitChar’
‘hexDigit’ → ‘hexDigitChar’
Descriptions of old parsers have been updated to accent some
Unicode-specific moments. For example, old description of ‘letter’
stated that it parses letters from “a” to “z” and from “A” to “Z”. This
is wrong, since it used ‘Data.Char.isAlpha’ predicate internally and
thus parsed many more characters.
New tests shows that I had wrong assumption about workings of this
particular function. This is not a problem, though, complete test-suite
will eliminate this sort of nuisance soon.
