YARRRML

YARRRML is a YAML-friendly syntax for RML mappings.

Note

Minimal generator. JSON-first. Good starting point for hand-tuning.

Example Output

Given a simple schema:

classes:
  Person:
    attributes:
      id: {identifier: true}
      name: {}

The generator produces YARRRML like:

mappings:
  Person:
    sources:
      - - data.json~jsonpath
        - $.items[*]
    s: ex:$(id)
    po:
      - p: rdf:type
        o: ex:Person
      - p: ex:name
        o: $(name)

Overview

• one mapping per LinkML class

• prefixes come from the schema

• subject from identifier slot (else key; else safe fallback)

• po for class-induced slots (slot aliases respected)

• emits rdf:type as a CURIE (e.g., ex:Person)

• JSON by default: sources: [[data.json~jsonpath, $.items[*]]]

Command Line

linkml generate yarrrml path/to/schema.yaml > mappings.yml
# CSV instead of JSON:
linkml generate yarrrml path/to/schema.yaml --source data.csv~csv
# class-based arrays:
linkml generate yarrrml path/to/schema.yaml --iterator-template "$.{Class}[*]"

Docs

CLI

gen-yarrrml

Generate YARRRML mappings from a LinkML schema.

gen-yarrrml [OPTIONS] YAMLFILE

Options

--source <source>

YARRRML source shorthand, e.g., data.json~jsonpath or data.csv~csv

--iterator-template <iterator_template>

JSONPath iterator template; supports {Class}, default: “$.items[*]”

-V, --version

Show the version and exit.

-f, --format <format>

Output format

Default:

'yml'

Options:

yml | yaml

--metadata, --no-metadata

Include metadata in output

Default:

True

--useuris, --metauris

Use class and slot URIs over model uris

Default:

True

-im, --importmap <importmap>

Import mapping file

--log_level <log_level>

Logging level

Default:

'WARNING'

Options:

CRITICAL | ERROR | WARNING | INFO | DEBUG

-v, --verbose

Verbosity. Takes precedence over –log_level.

--mergeimports, --no-mergeimports

Merge imports into source file (default=mergeimports)

--stacktrace, --no-stacktrace

Print a stack trace when an error occurs

Default:

False

Arguments

YAMLFILE

Required argument

Code

class linkml.generators.yarrrmlgen.YarrrmlGenerator(schema: str | TextIO | SchemaDefinition, format: str = 'yml', **kwargs)

LinkML -> YARRRML exporter.

serialize(**args) → str

Generate output in the required format

Parameters:

kwargs – Generator specific parameters

Returns:

Generated output

Limitations

• JSON-first by default

• One source per mapping

• Classes without an identifier are skipped

• Object slots: inlined: false → IRI; inlined: true → not materialized

• Iterators not derived from JSON Schema

• No per-slot JSONPath overrides

• CSV supported via –source