NAME¶
happy - the parser generator for Haskell
SYNOPSIS¶
happy [
OPTION]...
file [
OPTION]...
DESCRIPTION¶
This manual page documents briefly the
happy command.
This manual page was written for the Debian GNU/Linux distribution because the
original program does not have a manual page. Instead, it has documentation in
various other formats, including DVI, Info and HTML; see below.
Happy is a parser generator system for Haskell. `HAPPY' is a dyslexic
acronym for `A Yacc-like Haskell Parser generator'.
There are two types of grammar files,
file.y and
file.ly, with the
latter observing the reverse comment bird track convention (i.e. each code
line must begin with `>'). The examples distributed with
Happy are
all of the
.ly form.
Caveat: When using
hbc (Chalmers Haskell) the command argument structure
is slightly different. This is because the hbc run time system takes some
flags as its own (for setting things like the heap size, etc). This problem
can be circumvented by adding a single dash (`-') to your command line. So
when using a hbc generated version of Happy, the argument structure is:
happy - [
OPTION]...
file [
OPTION]...
OPTIONS¶
The programs follow the usual GNU command line syntax, with long options
starting with two dashes (`--'). A summary of options is included below. For a
complete description, see the other documentation.
- -h, --help
- Show summary of options.
- -v, --version
- Print version information on standard output then exit successfully.
- -a, --array
- Instructs Happy to generate a parser using an array-based shift reduce
parser. When used in conjunction with -g, the arrays will be
encoded as strings, resulting in faster parsers. Without -g,
standard Haskell arrays will be used.
- -g, --ghc
- Instructs Happy to generate a parser that uses GHC-specific extensions to
obtain faster code.
- -c, --coerce
- Use GHC's unsafeCoerce# extension to generate smaller faster
parsers. One drawback is that some type safety is lost, which means that a
parser generated with -c may compile fine but crash at run-time. Be
sure to compile your grammar without -c first to ensure it is
type-correct.
This option has quite a significant effect on the performance of the
resulting parser, but remember that parsers generated this way can only be
compiled by GHC 3.02 and above.
This option may only be used in conjuction with -g.
- -d, --debug
- Generate a parser that will print debugging information to stderr
at run-time, including all the shifts, reductions, state transitions and
token inputs performed by the parser.
This option may only be used in conjuction with -a.
- -i [FILE], --info[=FILE]
- Directs Happy to produce an info file containing detailed information
about the grammar, parser states, parser actions, and conflicts. Info
files are vital during the debugging of grammars.
The filename argument is optional, and if omitted the info file will be
written to FILE.info (where FILE is the input file name with
any extension removed).
- -o FILE, --outfile=FILE
- Specifies the destination of the generated parser module. If omitted, the
parser will be placed in FILE.hs, where FILE is the name of
the input file with any extension removed. If FILE is - the
generated parser is sent to the standard output.
- -m NAME, --magic-name=NAME
- Happy prefixes all the symbols it uses internally with either happy
or Happy. To use a different string, for example if the use of
happy is conflicting with one of your own functions, specify the
prefix using the -m option.
- -t DIR, --template=DIR
- Instructs Happy to use this directory when looking for template files:
these files contain the static code that Happy includes in every generated
parser. You shouldn't need to use this option if Happy is properly
configured for your computer.
- -l, --glr
- Instructs Happy to output a GLR parser instead of an LALR(1) parser.
- -k, --decode
- Causes the GLR parser to generate code for decoding the parse forest to a
list of semantic results (requires --ghc).
- -f, --filter
- Causes the GLR parser to filter out nodes which aren't required for the
semantic results (an experimental optimisation, requires --ghc).
FILES¶
/usr/share/happy-1.19.4
SEE ALSO¶
/usr/share/doc/happy, the Happy homepage
(http://haskell.org/happy/)
COPYRIGHT¶
Happy Version 1.19.4
Copyright (c) 1993-1996 Andy Gill, Simon Marlow; (c) 1997-2001 Simon Marlow
AUTHOR¶
This manual page was written by Michael Weber <michaelw@debian.org>, for
the Debian GNU/Linux system (but may be used by others).