Here's another example of a language that is defined using the language itself:
This document defines the Augmented BNF (ABNF) using ABNF:
https://tools.ietf.org/html/rfc5234#section-4
That is the ABNF-for-ABNFs!
Neat!
/Roger
-----Original Message-----
From: Costello, Roger L.
Sent: Saturday, January 10, 2015 3:43 PM
To:
Subject: Defining a language using itself
Hi Folks,
I think it is mind-blowing when a language is defined using the language itself.
This document defines the XML Schema language using XML Schema:
http://www.w3.org/TR/xmlschema11-1/#normative-schemaSchema
That is the XML schema-for-schemas!
This document defines the JSON Schema language using JSON Schema:
http://json-schema.org/draft-04/schema#
That is the JSON schema-for-schemas!
These two documents define the ANTLR grammar language using the ANTLR grammar:
https://github.com/antlr/grammars-v4/blob/master/antlr4/ANTLRv4Parser.g4
https://github.com/antlr/grammars-v4/blob/master/antlr4/ANTLRv4Lexer.g4
That is the ANTLR grammar-for-grammars!
Neat!
Do you know of other languages that are defined using the language itself?
/Roger
