ruby-antlr-parser

The ANTLR v4 grammar for Ruby.

Notes/Improve points

• Ruby is a very flexiable lanaguage. The parser should consider many possibile special usages. It impacts the performance of the parser, but I belive there still should be some solution to solve it.
• Currently version is already cover most of ruby grammar, took a reference with 2.6.0-rc2.
• Still several points should be mentioned:
  • Regex is not support well: an expression could be a / b + c / d, which include two / marks. While the regex in ruby is also a style like / ... .../. I still have not found solution for that. For the time being, I just simple identify tokens without blank between / ... .../ as regex, and identify others as normal tokens.
  • Due to performance issue, parse on some special files took long time. An example is given under ruby/test/with_problem/long_time_to_parse.rb. If I disable the rule of #ExprFunctionCall1 and #ExprFunctionCall2, the parser performance is improved far, but I cannot do that due to there are certainly functions without brackets.

Test

Step 1: set up enviorment

Firstly you should have antlr4 installed on your operation system. Then create an shortcut command likes antlr4 in your execution path. The content likes following:

#!/bin/sh

CLASSPATH=/usr/share/java/stringtemplate4.jar:/usr/share/java/antlr4.jar:/usr/share/java/antlr4-runtime.jar:/usr/share/java/antlr3-runtime.jar/:/usr/share/java/treelayout.jar
exec java -cp $CLASSPATH org.antlr.v4.Tool "$@"

Step 2: to compile and test the files

Please note that all command should be invoked under directory of ruby. Under the directory, enter the following command please:

./tool/compiletest.sh test/helloworld.rb

Antlr will compile the grammer files and to parse the test/helloworld.rb file.

There are several commands under the tool directory for your convience.

Contact

Any contribution and feedback on the project is highly appreciated. Any further questions, kindly contact with Gang ZHANG (gangz@emergentdesign.cn) please.