HAPPY
Section: Happy Parser Generator (1)
Updated: 2000-12-23
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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).
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- OPTIONS
-
- FILES
-
- SEE ALSO
-
- COPYRIGHT
-
- AUTHOR
-