Added Liquid Filter methods for UnitsML template

Gemfile

@@ -12,6 +12,8 @@ rescue StandardError
   nil
 end
 
+gem "lutaml", github: "lutaml/lutaml", branch: "main"
+gem "lutaml-model", github: "lutaml/lutaml-model", branch: "fix/xsd-target-namespace-prefix"
 gem "rake", "~> 13"
 gem "rspec"
 gem "rspec-html-matchers"

README.adoc

@@ -14,6 +14,7 @@ within a Metanorma document:
 * Enterprise Architect exported UML files in XMI format (`*.xmi`)
 * LutaML GML Dictionary files (`*.xml`)
 * JSON or YAML files (`*.json|*.yml|*.yaml`)
+* XML Schema files (`*.xsd`)
 
 == Installation
 
@@ -34,6 +35,8 @@ link:docs/usages/lutaml-gml.adoc[Usage with LutaML GML Dictionary by lutaml_gml_
 
 link:docs/usages/json_yaml.adoc[Usage with JSON or YAML files by data2text, yaml2text or json2text]
 
+link:docs/usages/lutaml-xsd.adoc[Usage with XML Schema files by lutaml_xsd]
+
 == Documentation
 
 Please refer to https://www.metanorma.org.

docs/usages/lutaml-xsd.adoc

@@ -0,0 +1,94 @@
+== Usage with LutaML XSD
+
+=== Overview
+
+The `lutaml_xsd` macro parses *XML Schema (XSD)* files through `lutaml-model`
+and exposes the parsed schema object to *Liquid* templates.
+
+=== Syntax
+
+[source,adoc]
+-----
+[lutaml_xsd,<path_to_xsd>,<context_name>[, option1=value1, option2=value2, ...]]
+----
+<your Liquid template here>
+----
+-----
+
+* `<path_to_xsd>`: Path to the XSD file to be processed.
+* `<context_name>`: The name of the context variable to use in the template.
+* `option1=value1, ...`: Optional parameters (<<options,supported options>>).
+
+[[options]]
+=== Options
+
+* `location`: Base URL or path for resolving `<xs:import>` and `<xs:include>`
+  statements in the XSD. When omitted, the directory of `<path_to_xsd>` is used.
+
+=== Liquid Template Context
+
+The context variable (e.g., `unitsml`) exposes the parsed
+`Lutaml::Xml::Schema::Xsd::Schema` object through its Liquid drop.
+
+Commonly used schema collections:
+
+* `element`: List of elements defined in the XSD.
+* `complex_type`: List of complex types defined in the XSD.
+* `simple_type`, `attribute`, `attribute_group`, `group`, `import`, and
+  `include`: Other schema components exposed by `lutaml-model`.
+
+Commonly used helpers:
+
+* `elements_sorted_by_name`, `complex_types_sorted_by_name`,
+  `attribute_groups_sorted_by_name`: Sorted schema collections.
+* `used_by`, `child_elements`, `attribute_elements`, and `referenced_type`:
+  Component helpers exposed by parsed XSD objects.
+
+=== Example: Listing Elements and Complex Types
+
+[source,adoc]
+-----
+= Elements
+[lutaml_xsd,path/to/unitsml.xsd,unitsml]
+----
+{% for element in unitsml.elements_sorted_by_name %}
+Name: *{{ element.name }}*
+Type: *{{ element.type }}*
+Used by: {{ element.used_by | map: "name" | join: ", " }}
+{% endfor %}
+----
+
+= ComplexTypes
+[lutaml_xsd,path/to/unitsml.xsd,unitsml]
+----
+{% for complex_type in unitsml.complex_types_sorted_by_name %}
+Name: *{{ complex_type.name }}*
+Children: {{ complex_type.child_elements | map: "name" | join: ", " }}
+Attributes: {{ complex_type.attribute_elements | map: "name" | join: ", " }}
+{% endfor %}
+----
+-----
+
+=== Example: Using with Remote XSD and Options
+
+[source,adoc]
+-----
+[lutaml_xsd,path/to/omml.xsd,omml, location=https://raw.githubusercontent.com/t-yuki/ooxml-xsd/refs/heads/master]
+----
+{% for element in omml.element %}
+Name: *{{ element.name }}*
+Type: *{{ element.type }}*
+{% endfor %}
+----
+-----
+
+=== Use Cases
+
+* Generate documentation for XML schemas.
+* Extract and list schema elements and types or other details.
+* Customize output using Liquid templates.
+
+=== Notes
+
+* The macro supports local files at `<path_to_xsd>`.
+* You can use all standard *Liquid* template features for formatting and logic.

lib/metanorma-plugin-lutaml.rb

@@ -3,7 +3,9 @@
 require "metanorma/plugin/lutaml/json2_text_preprocessor"
 require "metanorma/plugin/lutaml/yaml2_text_preprocessor"
 require "metanorma/plugin/lutaml/data2_text_preprocessor"
+require "metanorma/plugin/lutaml/base_preprocessor"
 require "metanorma/plugin/lutaml/lutaml_preprocessor"
+require "metanorma/plugin/lutaml/lutaml_xsd_preprocessor"
 require "metanorma/plugin/lutaml/lutaml_uml_datamodel_description_preprocessor"
 require "metanorma/plugin/lutaml/lutaml_ea_xmi_preprocessor"
 require "metanorma/plugin/lutaml/lutaml_xmi_uml_preprocessor"