Sparql

This module offers a SPARQL parser for elixir.

Files

• sparql.xrl: contains the rules for tokenizing queries, can be transformed into a sparql.erl file by using :leex
• sparql.erl: a compiled file that contains a tokenizer for sparql queries
• sparql.yrl: contains the rules for parsing tokenized queries into elixir data structures

Usage

To use in iex simply run

> :leex.file('parser-generator/sparql-tokenizer.xrl')
> c("parser-generator/sparql-tokenizer.erl")

To tokenize queries you can

> :"sparql-tokenizer".string('select ?s ?p ?o where { ?s ?p ?o }')
>
> {:ok,
  [
    {:select, 1},
    {:variable, 1, :s},
    {:variable, 1, :p},
    {:variable, 1, :o},
    {:where, 1},
    {:"{", 1},
    {:variable, 1, :s},
    {:variable, 1, :p},
    {:variable, 1, :o},
    {:"}", 1}
  ], 1}

To parse the tokenizers produce first load the parser

> :yecc.file('parser-generator/sparql-parser.yrl')
> c("parser-generator/sparql-parser.erl")

Extract the tokenized query

> {:ok, ps, 1} = :sparql-tokenizer.string('?s ?p ?o.')

And the parse it

> :"sparql-parser".parse(ps)

Or parse a custom tokenized string

> :"sparql-parser".parse([{:variable, 1, :s},{:variable, 1, :s}])

Compiling your own tokenizer

Compiling your own parser

Installation

If available in Hex, the package can be installed by adding sparql to your list of dependencies in mix.exs:

def deps do
  [
    {:sparql, "~> 0.1.0"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/sparql.