MVEL 1.3

MVEL (MVFLEX Expression Language) Version 1.3
Fork of MVEL Version 1.3.14 which is still in user by certain projects.
Documentation can be found in the Wiki.

The more recent 2.* releases of MVEL can be found here

Installation

Download the mvel .jar file from the target directory. MVEL 1.3 is available as a single .jar file with no external dependencies.

MVEL Shell

MVEL comes with a simple shell. You can start the shell with the following command:

$ java -jar mvel-1.3.14.jar
Welcome to MVEL!

The shell command help; gives some hints on how to use the shell. Shell commands must end with a ';'.

mvel$ help;
Commands
--------
echo            -   toggles output echo on/off
template        -   use the template parser shell
stacktrace      -   toggles stacktraces on/off
benchmark       -   toggles benchmark mode on/off
exectime        -   toggles execution time display on/off
clear           -   clears all variables
quit            -   exits the shell

The Shell allows to try out the various features of MVEL:

mvel$ 3 + 5
OUT: 8
mvel$ map = ['key':'value', 'color':'green']
OUT: {color=green, key=value}
mvel$ map.class
OUT: class java.util.HashMap
mvel$

The shell will store variables entered while the shell runs:

mvel$ x = 5
OUT: 5
mvel$ y = x + 7
OUT: 12

When you enter multiple statements on a single line the statements have to be seperated by a semi-colon. The result of the expression is the result of the last statement:

mvel$ firstName = "John"; lastName = "Doe"
OUT: Doe

You can use clear; to clear all variables stored at runtime of the shell.

mvel$ clear;
CLEARED VARIABLES.