About

Parser pkg contains an ANTLR4 grammar file which represents the DSL used to declare PolicyTheorems and Relationships within ACP Core

Examples

The relationship_document production rule consumes all the input stream looking for a relationship. Any trailing input will cause an error. example:

resource:foo#owner@did:example:bob

The relationship_set production rule consumes as many relationships as it can, greedily. Relationships are separated by whitespace characters as per the WS lexeme eg (\t \n\r) Trailing input in the input stream causes an error.

example:

resource:foo#owner@did:example:bob
resource:foo#reader@group:admin#member

// relationship sets can have comments until EOL

resource:foo#year@year:2024 

Theorems are parsed by the policy_theorem production rule. It is also a greed rule, which consumes all of the input stream or errors.

Ex:

Authorizations {
    file:abc#reader@did:example:bob
    !file:abc#owner@did:example:bob //coment until EOL
}

Delegations {
    did:example:alice > file:abc#reader // alice can manage `reader` for `file:abc`
}

Developing

Getting ANTLR

Installing ANTLR can be done simply using the pip package antlr4-tools as explained in the (documentation)[https://github.com/antlr/antlr4/blob/master/doc/getting-started.md#getting-started-the-easy-way-using-antlr4-tools].

[ ] TODO: A Dockerfile + script for deterministic generation

Parser Generation

The parser for the grammar can be generated using tools/generate-parser.sh using the project root as PWD.