Getting Started with ANTLR v4
Hi and welcome to the version 4 release of ANTLR! It's named after the fearless hero of the Crazy Nasty-Ass Honey Badger since ANTLR v4 takes whatever you give it--it just doesn't give a crap! See Why do we need ANTLR v4? and the preface of the ANTLR v4 book.
ANTLR is really two things: a tool that translates your grammar to a parser/lexer in Java (or other target language) and the runtime needed by the generated parsers/lexers. Even if you are using the ANTLR Intellij plug-in or ANTLRWorks to run the ANTLR tool, the generated code will still need the runtime library.
The first thing you should do is probably download and install a development tool plug-in. Even if you only use such tools for editing, they are great. Then, follow the instructions below to get the runtime environment available to your system to run generated parsers/lexers. In what follows, I talk about antlr-4.7.1-complete.jar, which has the tool and the runtime and any other support libraries (e.g., ANTLR v4 is written in v3).
If you are going to integrate ANTLR into your existing build system using mvn, ant, or want to get ANTLR into your IDE such as eclipse or intellij, see Integrating ANTLR into Development Systems.
- Install Java (version 1.6 or higher)
$ cd /usr/local/lib $ curl -O http://www.antlr.org/download/antlr-4.7.1-complete.jar
Or just download in browser from website:
and put it somewhere rational like
$ export CLASSPATH=".:/usr/local/lib/antlr-4.7.1-complete.jar:$CLASSPATH"
It's also a good idea to put this in your
.bash_profile or whatever your startup script is.
- Create aliases for the ANTLR Tool, and
$ alias antlr4='java -Xmx500M -cp "/usr/local/lib/antlr-4.7.1-complete.jar:$CLASSPATH" org.antlr.v4.Tool' $ alias grun='java org.antlr.v4.gui.TestRig'
(Thanks to Graham Wideman)
- Install Java (version 1.6 or higher)
- Download antlr-4.5.3-complete.jar (or whatever version) from http://www.antlr.org/download/
Save to your directory for 3rd party Java libraries, say
antlr-4.5.3-complete.jarto CLASSPATH, either:
- Permanently: Using System Properties dialog > Environment variables > Create or append to
- Temporarily, at command line:
- Create short convenient commands for the ANTLR Tool, and TestRig, using batch files or doskey commands:
- Batch files (in directory in system PATH) antlr4.bat and grun.bat
java org.antlr.v4.Tool %*
java org.antlr.v4.gui.TestRig %*
- Or, use doskey commands:
doskey antlr4=java org.antlr.v4.Tool $* doskey grun =java org.antlr.v4.gui.TestRig $*
Testing the installation
Either launch org.antlr.v4.Tool directly:
$ java org.antlr.v4.Tool ANTLR Parser Generator Version 4.7.1 -o ___ specify output directory where all output is generated -lib ___ specify location of .tokens files ...
or use -jar option on java:
$ java -jar /usr/local/lib/antlr-4.7.1-complete.jar ANTLR Parser Generator Version 4.7.1 -o ___ specify output directory where all output is generated -lib ___ specify location of .tokens files ...
A First Example
In a temporary directory, put the following grammar inside file Hello.g4: Hello.g4
// Define a grammar called Hello grammar Hello; r : 'hello' ID ; // match keyword hello followed by an identifier ID : [a-z]+ ; // match lower-case identifiers WS : [ \t\r\n]+ -> skip ; // skip spaces, tabs, newlines
Then run ANTLR the tool on it:
$ cd /tmp $ antlr4 Hello.g4 $ javac Hello*.java
Now test it:
$ grun Hello r -tree hello parrt ^D (r hello parrt) (That ^D means EOF on unix; it's ^Z in Windows.) The -tree option prints the parse tree in LISP notation. It's nicer to look at parse trees visually. $ grun Hello r -gui hello parrt ^D
That pops up a dialog box showing that rule
r matched keyword
hello followed by identifier
Book source code
The book has lots and lots of examples that should be useful too. You can download them here for free:
Also, there is a large collection of grammars for v4 at github: