Ruby Grammar

Question

I'm looking for Ruby grammar in BNF form. Is there an official version?

Kenji Noguchi · Answer 1 · 2013-05-18T22:05:33.870

The YACC syntax is in the Ruby source. Download it and run the bundled utiliy to get the readable syntax.

wget ftp://ftp.ruby-lang.org/pub/ruby/2.0/ruby-2.0.0-p195.tar.gz
tar xvzf ruby-2.0.0-p195.tar.gz
cd ruby-2.0.0-p195
ruby sample/exyacc.rb < parse.y

Output sample (total 918 lines for the v2.0.0-p195)

program         : top_compstmt
                ;

top_compstmt    : top_stmts opt_terms
                ;

top_stmts       : none
                | top_stmt
                | top_stmts terms top_stmt
                | error top_stmt
                ;

top_stmt        : stmt
                | keyword_BEGIN
                  '{' top_compstmt '}'
                ;

bodystmt        : compstmt
                  opt_rescue
                  opt_else
                  opt_ensure
                ;

compstmt        : stmts opt_terms
                ;

now just `git clone https://github.com/ruby/ruby ; cd ruby ; ruby sample/exyacc.rb < parse.y` — Lance, Jun 08 '14 at 07:09

score 15 · Accepted Answer · edited Oct 15 '15 at 02:14

15

Yes, there is one Ruby BNF syntax by the University of buffalo.

Edit: I've also found this alternate Ruby BNF syntax.

edited Oct 15 '15 at 02:14

Kevin Chen

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answered Mar 19 '09 at 16:55

Adrian Grigore

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5

But I don't think the first link is to an "official" grammar. I hear that the closest thing to an official grammar for Ruby is the parse.y file. – Eric Walker Jan 01 '11 at 00:10
6

Unfortunately, the similar UoB and the njit grammars are completely wrong. There is no do in a for loop, extend and include statements are missing and exception variables are missing. – Feb 07 '13 at 03:46

GutenYe · Answer 3 · 2011-08-31T01:54:51.407

5

also an official version: Ruby Draft Specification. you can find the grammar there.

Ruby Draft Specification: http://ruby-std.netlab.jp. the server is down, but you can download it from http://www.ipa.go.jp/osc/english/ruby

edited Aug 31 '11 at 01:54

answered Jul 07 '11 at 04:29

GutenYe

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Link is not accessible without a password. – Jeroen Heijmans Aug 30 '11 at 08:41
1

thanks for the report. The old link worked when I posted that comment. but I've add a new link. It should work now. – GutenYe Aug 31 '11 at 01:55
Very cool.I see that its for 1.8.7. Is there a newer one for Ruby 2.0? – sunnyrjuneja Nov 30 '12 at 04:40

Ruby Grammar

3 Answers3

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