How to install the Perl module "JavaScript" on Unix

This article deals with installing JavaScript on Unix, specifically FreeBSD. Although FreeBSD comes with a port of SpiderMonkey, in /usr/ports/lang/spidermonkey, it doesn't seem to work with the Perl JavaScript module. Following the advice given in the JavaScript module, I reinstalled the spidermonkey library myself and built against that.

Download the Javascript source code from Mozilla:

wget http://ftp.mozilla.org/pub/mozilla.org/js/js-1.7.0.tar.gz

Unpack this file and go to the subdirectory js/src.
Run the makefile like this:
```
gmake -f Makefile.ref
```

This produces an error message:

config.mk:150: config/FreeBSD7.2-RELEASE.mk: No such file or directory
cat: ../../dist/FreeBSD7.2-RELEASE_DBG.OBJ/nspr/Version: No such file or directory
gmake: *** No rule to make target `config/FreeBSD7.2-RELEASE.mk'.  Stop.

Copy the file config/Linux_All.mk to config/FreeBSD7.2-RELEASE.mk, or whatever it said in the equivalent message.
Run gmake again.
The output files are in the directory FreeBSD7.2-RELEASE_DBG.OBJ/.
Copy the header files (*.h) and tables (*.tbl) from the src directory to the FreeBSD7.2-RELEASE_DBG.OBJ.
```
[ben@mikan] src 575 $ cp *.tbl *.h FreeBSD7.2-RELEASE_DBG.OBJ/
```
Note that the header file jsautocfg.h is only in the FreeBSD7.2-RELEASE_DBG.OBJ directory, so if you compile against the header files in src, you will get a huge number of errors from the C compiler, starting off with the line
```
/home/ben/software/js/js/src/jstypes.h:245:71: error: jsautocfg.h: No such file or directory
```

Set up the environment to link against the compiled library:

export JS_LIB=/home/ben/software/js/js/src/FreeBSD7.2-RELEASE_DBG.OBJ/
export JS_INC=/home/ben/software/js/js/src/FreeBSD7.2-RELEASE_DBG.OBJ/

Run cpan to install JavaScript:
```
cpan JavaScript
```
In my case this required installing one prerequisite, Test::Exception. Remember that if cpan fails, you can always download the distribution from CPAN and install it with
```
perl Makefile.PL
make
make test
make install
```