Alex is a tool for generating lexical analysers in Haskell.
It takes a description of tokens based on regular
expressions and generates a Haskell module containing code
for scanning text efficiently. It is similar to the tool
lex or flex for C/C++.
Changes
Changes in 3.1.7:
Add support for %encoding directive
(allows to control --latin1 from inside Alex scripts)
Make code forward-compatible with in-progress proposals
Suppress more warnings
Changes in 3.1.6:
sdist for 3.1.5 was mis-generated, causing it to ask for Happy
when building.
Changes in 3.1.5:
Generate less warning-laden code, and suppress other warnings.
Bug fixes.
Changes in 3.1.4:
Add Applicative/Functor instances for GHC 7.10
Changes in 3.1.3:
Fix for clang (XCode 5)
Changes in 3.1.2:
Add missing file to extra-source-files
Changes in 3.1.1:
Bug fixes (#24, #30, #31, #32)
Changes in 3.1.0:
necessary changes to work with GHC 7.8.1
Changes in 3.0 (since 2.3.5)
Unicode support (contributed mostly by Jean-Philippe Bernardy,
with help from Alan Zimmerman).
An Alex lexer now takes a UTF-8 encoded byte sequence as input
(see Section 5.1, “Unicode and UTF-8”. If you are using the
“basic” wrapper or one of the other wrappers that takes a
Haskell String as input, the string is automatically encoded
into UTF-8 by Alex. If your input is a ByteString, you are
responsible for ensuring that the input is UTF-8 encoded. The
old 8-bit behaviour is still available via the –latin1
option.
Alex source files are assumed to be in UTF-8, like Haskell
source files. The lexer specification can use Unicode
characters and ranges.
alexGetChar is renamed to alexGetByte in the generated code.
There is a new option, --latin1, that restores the old
behaviour.
Alex now does DFA minimization, which helps to reduce the size
of the generated tables, especially for lexers that use Unicode.
