abnf

For more information on the flavor of ABNF (Augmented Backus-Naur Form) supported by this project, see RFC 5234 and RFC 7405.

Installation:

npm install -g abnf

Example:

import { parseFile } from "abnf";
const rules = await parseFile("myfile.abnf");

CLI

There are a few binaries included:

abnfcheck

Check the given ABNF file for correctness.

abnfast

Output the generated abstract syntax tree for the ABNF input. This output is mostly diagnostic in nature, not really meant to be parsed.

abnfgen

Generate a Peggy grammar from the ABNF. The idea is that you could then annotate this grammar with actions in order to create a useful parser.

abnftest

Using an ABNF, test inputs to see if they match. Returns the Peggy parse tree, which will likely be somewhat confusing until you're familiar with Peggy.

Workflow

$ cat << EOF > foo.abnf
f = "abc"
EOF
$ abnf_gen foo.abnf
$ cat foo.peggy
f
  = "abc"i
$ abnf_test foo.abnf -t abc
'abc'
$ abnf_test foo.peggy -t ab
Error: Expected "abc" but "a" found.
 --> command line:1:1
  |
1 | ab
  | ^

API

.parseFile(input)

Parse the file with the given name, returning a promise for a Rules object.

.parseString(input, grammarSource = "unknown")

Parse the given string and return a Rules object. The grammarSource is the name of the file that the input came from.

.parseStream(stream, grammarSource = "stdin")

Read the stream, parse it, and return a promise for a Rules object. The grammarSource is the name of the file that the input came from.

Returned Rules object shape

Rules.first

The name of the first rule in the input grammar.

Rules.defs

A hash of Rule objects indexed by uppercase rulename.

Rules.refs

An array of RuleRef objects.

Rule.name

The name of the rule

Rule.loc

The Peggy location in the input file where the rule name was defined

Rule.def

The definition of the rule. More information forthcoming.

RuleRef.name

The name of the rule that was referenced

RuleRef.loc

The Peggy location in the input file where the rule name was referenced.

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