Lrama¶ ↑

Overview¶ ↑

Lrama is LALR (1) parser generator written by Ruby. The first goal of this project is providing error tolerant parser for CRuby with minimal changes on CRuby parse.y file.

Installation¶ ↑

Lrama’s installation is simple. You can install it via RubyGems.

$ gem install lrama

From source codes, you can install it as follows:

$ cd "$(lrama root)"
$ bundle install
$ bundle exec rake install
$ bundle exec lrama --version
lrama 0.6.11

Usage¶ ↑

Lrama is a command line tool. You can generate a parser from a grammar file by running lrama command.

# "y.tab.c" and "y.tab.h" are generated
$ lrama -d sample/parse.y

Specify the output file with -o option. The following example generates “calc.c” and “calc.h”.

# "calc", "calc.c", and "calc.h" are generated
$ lrama -d sample/calc.y -o calc.c && gcc -Wall calc.c -o calc && ./calc
Enter the formula:
1
=> 1
1+2*3
=> 7
(1+2)*3
=> 9

Supported Ruby version¶ ↑

Lrama is executed with BASERUBY when building ruby from source code. Therefore Lrama needs to support BASERUBY, currently 2.5, or later version.

This also requires Lrama to be able to run with only default gems because BASERUBY runs with --disable=gems option.

License¶ ↑

See LEGAL.md file.