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| author | Takenobu Tani <takenobu.hs@gmail.com> | 2018-01-21 12:08:59 -0500 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2018-01-21 12:09:00 -0500 |
| commit | 4a13c5b1f4beb53cbf1f3529acdf3ba37528e694 (patch) | |
| tree | cfce02f26d602175f99699763b0c654b4b65033e /libraries/ghc-boot-th | |
| parent | 180ca65ff6d1b4f3f4cdadc569fd4de107be14db (diff) | |
| download | haskell-4a13c5b1f4beb53cbf1f3529acdf3ba37528e694.tar.gz | |
Implement underscores in numeric literals (NumericUnderscores extension)
Implement the proposal of underscores in numeric literals.
Underscores in numeric literals are simply ignored.
The specification of the feature is available here:
https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/000
9-numeric-underscores.rst
For a discussion of the various choices:
https://github.com/ghc-proposals/ghc-proposals/pull/76
Implementation detail:
* Added dynamic flag
* `NumericUnderscores` extension flag is added for this feature.
* Alex "Regular expression macros" in Lexer.x
* Add `@numspc` (numeric spacer) macro to represent multiple
underscores.
* Modify `@decimal`, `@decimal`, `@binary`, `@octal`, `@hexadecimal`,
`@exponent`, and `@bin_exponent` macros to include `@numspc`.
* Alex "Rules" in Lexer.x
* To be simpler, we have only the definitions with underscores.
And then we have a separate function (`tok_integral` and `tok_frac`)
that validates the literals.
* Validation functions in Lexer.x
* `tok_integral` and `tok_frac` functions validate
whether contain underscores or not.
If `NumericUnderscores` extensions are not enabled,
check that there are no underscores.
* `tok_frac` function is created by merging `strtoken` and
`init_strtoken`.
* `init_strtoken` is deleted. Because it is no longer used.
* Remove underscores from target literal string
* `parseUnsignedInteger`, `readRational__`, and `readHexRational} use
the customized `span'` function to remove underscores.
* Added Testcase
* testcase for NumericUnderscores enabled.
NumericUnderscores0.hs and NumericUnderscores1.hs
* testcase for NumericUnderscores disabled.
NoNumericUnderscores0.hs and NoNumericUnderscores1.hs
* testcase to invalid pattern for NumericUnderscores enabled.
NumericUnderscoresFail0.hs and NumericUnderscoresFail1.hs
Test Plan: `validate` including the above testcase
Reviewers: goldfire, bgamari
Reviewed By: bgamari
Subscribers: carter, rwbarton, thomie
GHC Trac Issues: #14473
Differential Revision: https://phabricator.haskell.org/D4235
Diffstat (limited to 'libraries/ghc-boot-th')
| -rw-r--r-- | libraries/ghc-boot-th/GHC/LanguageExtensions/Type.hs | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/libraries/ghc-boot-th/GHC/LanguageExtensions/Type.hs b/libraries/ghc-boot-th/GHC/LanguageExtensions/Type.hs index 3e8c2a0e15..2b06c851a8 100644 --- a/libraries/ghc-boot-th/GHC/LanguageExtensions/Type.hs +++ b/libraries/ghc-boot-th/GHC/LanguageExtensions/Type.hs @@ -133,4 +133,5 @@ data Extension | StrictData | MonadFailDesugaring | EmptyDataDeriving + | NumericUnderscores deriving (Eq, Enum, Show, Generic) |