Windows

1. Unzip the file you downloaded into the directory you want JFlex in (using something like WinZip). If you unzipped it to say C:\, the following directory structure should be generated:

   C:\JFlex\                          
         +--bin\                   (start scripts) 
         +--doc\                   (FAQ and manual)
         +--examples\ 
                  +--binary\       (scanning binary files)
                  +--byaccj\       (calculator example for BYacc/J)
                  +--cup\          (calculator example for cup)
                  +--interpreter\  (interpreter example for cup)
                  +--java\         (Java lexer specification) 
                  +--simple\       (example scanner)
                  +--simple-maven\ (example with maven)
                  +--standalone\   (a simple standalone scanner)
                  +--standalone-maven\  (above with maven)
         +--lib\                   (the precompiled classes) 
         +--src\ 
             +--JFlex\             (source code of JFlex) 
             +--JFlex\gui          (source code of JFlex UI classes)
             +--java_cup\runtime\  (source code of cup runtime classes)
   

2. Edit the file bin\jflex.bat (in the example it's C:\JFlex\bin\jflex.bat) such that
   • JAVA_HOME contains the directory where your Java JDK is installed (for instance C:\java) and
   • JFLEX_HOME the directory that contains JFlex (in the example: C:\JFlex)

3. Include the bin\ directory of JFlex in your path. (the one that contains the start script, in the example: C:\JFlex\bin).

Unix with tar archive

To install JFlex on a Unix system, follow these two steps:

• Decompress the archive into a directory of your choice with GNU tar, for instance to /usr/share:

  tar -C /usr/share -xvzf jflex-1.4.3.tar.gz

  (The example is for site wide installation. You need to be root for that. User installation works exactly the same way--just choose a directory where you have write permission)

• Make a symbolic link from somewhere in your binary path to bin/jflex, for instance:

  ln -s /usr/share/JFlex/bin/jflex /usr/bin/jflex

  If the Java interpreter is not in your binary path, you need to supply its location in the script bin/jflex.

You can verify the integrity of the downloaded file with the MD5 checksum available on the JFlex download page. If you put the checksum file in the same directory as the archive, you run:

md5sum --check jflex-1.4.3.tar.gz.md5

It should tell you

jflex-1.4.3.tar.gz: OK

Linux with RPM

• become root
• issue
  rpm -U jflex-1.4.3-0.rpm

You can verify the integrity of the downloaded rpm file with

rpm --checksig jflex-1.4.3-0.rpm

Running JFlex

jflex <options> <inputfiles>

It is also possible to skip the start script in bin\ and include the file lib\JFlex.jar in your CLASSPATH environment variable instead.

Then you run JFlex with:

java JFlex.Main <options> <inputfiles>

The input files and options are in both cases optional. If you don't provide a file name on the command line, JFlex will pop up a window to ask you for one.

JFlex knows about the following options:

-d <directory>
writes the generated file to the directory <directory>

--skel <file>
uses external skeleton <file>. This is mainly for JFlex maintenance and special low level customisations. Use only when you know what you are doing! JFlex comes with a skeleton file in the src directory that reflects exactly the internal, pre-compiled skeleton and can be used with the -skel option.

--nomin
skip the DFA minimisation step during scanner generation.

--jlex
tries even harder to comply to JLex interpretation of specs.

--dot
generate graphviz dot files for the NFA, DFA and minimised DFA. This feature is still in alpha status, and not fully implemented yet.

--dump
display transition tables of NFA, initial DFA, and minimised DFA

--verbose or -v
display generation progress messages (enabled by default)

--quiet or -q
display error messages only (no chatter about what JFlex is currently doing)

--time
display time statistics about the code generation process (not very accurate)

--version
print version number

--info
print system and JDK information (useful if you'd like to report a problem)

--pack
use the %pack code generation method by default

--table
use the %table code generation method by default

--switch
use the %switch code generation method by default

--help or -h
print a help message explaining options and usage of JFlex.