CDDL conversion utilities

This little set of tools provides a number of command line utilities for converting to and from CDDL.

In addition, the 0.4 releases contain a growing preview of the new capabilities of the cddlc tool that will replace the classic cddl tool, see below at the end of the README.

gem install cddlc

cddlc knows the following formats:

• .cddl: CDDL as defined in RFC8610
• .cddlj: JSON form of CDDL (the YIN to the YANG)
• .cddly: The same JSON form, but serialized in YAML.

These targets are identified by -t cddl, -t json (or -t neat naming the JSON prettyprinter), -t yaml. These can be abbreviated (but don't do that in scripts).

With -t enum, cddlc generates C-style enumeration type declarations from integer keys used in a map.

Apart from creating enum declarations, the current version only can transform from input CDDL to one of the JSON/YAML formats of CDDL.

• cddlc foo.cddl > foo.cddlj
• cddlc -tyaml foo.cddl > foo.cddly
• cddlc -ty foo.cddl > foo.cddly

Output is to stdout, input from one or more files given as command line arguments (use - for standard input).

cddlc comes with a curated selection of CDDL rules from published RFCs.

New in 0.4.1: rfc9597.cddl rfc9528.cddl rfc9526.cddl rfc9431.cddl rfc9360.cddl rfc9594-sign_info_entry-with-a-gene.cddl rfc9594-example-extended-scope-text.cddl rfc9594-example-extended-scope-aif.cddl rfc9594-get_creds.cddl rfc9594-error-handling.cddl rfc9594-sign_info-parameter.cddl rfc9594-example-scope-text.cddl rfc9594-example-scope-aif.cddl

These files can be used with import/include statements in CDDL models or directly from the command line with -i/-I arguments.

Get a full list of files included via:

$ gem contents cddlc | sed -n 's,.*/data/,,p'

...or, to get the full filenames:

$ gem contents cddlc | grep /data/

The 0.4.x revisions contain a growing preview of the new cddlc CDDL full validator implementation.

Usage: cddlc [options] [-e cddl | file.cddl... | -]
    ...
    -c, --cbor-validate=FILE   Validate CBOR file against CDDL grammar
    -j, --json-validate=FILE   Validate JSON file against CDDL grammar
    -d, --diag-validate=FILE   Validate EDN file against CDDL grammar
    -eCDDL                     CDDL model on command line

E.g.,

$ echo '"ab"' | cddlc test/21-cat.cddl --diag-validate=-
$ echo '"foo"' | cddlc test/21-cat.cddl -d-

(- stands for standard input, here in EDN CBOR diagnostic notation, produced via echo, which removes one layer of quotes on the command line).

Limitations (i.e., why this is a preview at this very moment):

• Only a small set of control operators have been ported over: .cat, .det, .plus, .size, .bits, .default, .feature, .regexp, .abnf, .abnfb.
• CDDL groups have not been ported over yet.

The new validator collects information during validation. This collected information will be made available via a number of mechanisms, which are also implementation TODOs at this time:

• First the CBOR diagnostic notation pretty printer from the classic cddl tool will be ported and completed.
• The information collection will also enable better error messages. The error message reporter will format them in a way that aids finding the reason for the lack of a match. (Right now the error messages are a YAML dump of the collected information. Note that the format of the collected information is subject to change.)

A port of the cddl generator is next, at which point cddlc will be fully subsuming the classic cddl tool.