roslaunch.xsd

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
  
  <xs:simpleType name="SubstitutionType">
    <xs:restriction base="xs:string">
      <xs:pattern value="$\(anon .*|$\(arg .*|$\(dirname .*|$\(env .*|$\(eval .*|$\(find .*|$\(optenv .*"/>
    </xs:restriction>
  </xs:simpleType>
  
  <xs:simpleType name="BoolType">
    <xs:union memberTypes="SubstitutionType">
      <xs:simpleType>
        <xs:restriction base='xs:string'>
          <xs:enumeration value='true'/>
          <xs:enumeration value='false'/>
        </xs:restriction>
      </xs:simpleType>
    </xs:union>
  </xs:simpleType>
  
  <xs:simpleType name="StringType">
    <xs:union memberTypes="SubstitutionType">
      <xs:simpleType>
        <xs:restriction base='xs:string'>
          <xs:pattern value="[^$].*" />
        </xs:restriction>
      </xs:simpleType>
      <xs:simpleType>
        <xs:restriction base='xs:string'>
          <xs:enumeration value=''/>
        </xs:restriction>
      </xs:simpleType>
    </xs:union>
  </xs:simpleType>
  
  <xs:element name='launch'>
    <xs:complexType>
      <xs:choice minOccurs='0' maxOccurs='unbounded'>
        <xs:element ref='node'/>
        <xs:element ref='machine'/>
        <xs:element ref='include'/>
        <xs:element ref='remap'/>
        <xs:element ref='env'/>
        <xs:element ref='param'/>
        <xs:element ref='rosparam'/>
        <xs:element ref='group'/>
        <xs:element ref='test'/>
        <xs:element ref='arg'/>
      </xs:choice>
      <xs:attribute name='deprecated' type='StringType'/>
    </xs:complexType>
  </xs:element>
  
  <xs:element name='arg'>
    <xs:annotation>
      <xs:documentation>
        Specifies arguments passed via command-line, via an include, or declared for higher-level files.
        Args are not global. Use $(arg name) to read an argument.
      </xs:documentation>
    </xs:annotation>
    <xs:complexType>
      <xs:attribute name='if' type='StringType'/>
      <xs:attribute name='unless' type='StringType'/>
      <xs:attribute name='name' type='StringType' use='required'/>
      <xs:attribute name='value' type='StringType'/>
      <xs:attribute name='default' type='StringType'/>
      <xs:attribute name='doc' type='StringType'/>
    </xs:complexType>
  </xs:element>
  
  <xs:element name='env'>
    <xs:annotation>
      <xs:documentation>
        Set environment variables on nodes that are launched.
        When used inside of launch tag, only applies to nodes declared after.
      </xs:documentation>
    </xs:annotation>
    <xs:complexType>
      <xs:attribute name='if' type='StringType'/>
      <xs:attribute name='unless' type='StringType'/>
      <xs:attribute name='name' type='StringType' use='required'/>
      <xs:attribute name='value' type='StringType' use='required'/>
    </xs:complexType>
  </xs:element>
  
  <xs:element name='group'>
    <xs:complexType>
      <xs:choice minOccurs='0' maxOccurs='unbounded'>
        <xs:element ref='group'/>
        <xs:element ref='node'/>
        <xs:element ref='machine'/>
        <xs:element ref='include'/>
        <xs:element ref='remap'/>
        <xs:element ref='env'/>
        <xs:element ref='param'/>
        <xs:element ref='rosparam'/>
        <xs:element ref='test'/>
        <xs:element ref='arg'/>
      </xs:choice>
      <xs:attribute name='if' type='StringType'/>
      <xs:attribute name='unless' type='StringType'/>
      <xs:attribute name='ns' type='StringType'/>
      <xs:attribute name='clear_params' type="BoolType"/>
    </xs:complexType>
  </xs:element>
  
  <xs:element name='include'>
    <xs:complexType>
      <xs:choice minOccurs='0' maxOccurs='unbounded'>
        <xs:element ref='env'/>
        <xs:element ref='arg'/>
      </xs:choice>
      <xs:attribute name='if' type='StringType'/>
      <xs:attribute name='unless' type='StringType'/>
      <xs:attribute name='file' type='StringType' use='required'/>
      <xs:attribute name='ns' type='StringType'/>
      <xs:attribute name='env-loader' type='StringType'/>
      <xs:attribute name='clear_params' type="BoolType"/>
      <xs:attribute name='pass_all_args' type="BoolType"/>
    </xs:complexType>
  </xs:element>
  
  <xs:element name='node'>
    <xs:complexType>
      <xs:choice minOccurs='0' maxOccurs='unbounded'>
        <xs:element ref='env'/>
        <xs:element ref='remap'/>
        <xs:element ref='rosparam'/>
        <xs:element ref='param'/>
      </xs:choice>
      <xs:attribute name='if' type='StringType'/>
      <xs:attribute name='unless' type='StringType'/>
      <xs:attribute name='pkg' type='StringType' use='required'/>
      <xs:attribute name='type' type='StringType' use='required'/>
      <xs:attribute name='name' type='StringType'/>
      <xs:attribute name='args' type='StringType'/>
      <xs:attribute name='machine' type='StringType'/>
      <xs:attribute name='respawn' type="BoolType"/>
      <xs:attribute name='respawn_delay' type='StringType'/>
      <xs:attribute name='required' type="BoolType"/>
      <xs:attribute name='clear_params' type="BoolType"/>
      <xs:attribute name='output'>
        <xs:simpleType>
          <xs:union memberTypes="SubstitutionType">
            <xs:simpleType>
              <xs:restriction base='xs:string'>
                <xs:enumeration value='log'/>
                <xs:enumeration value='screen'/>
              </xs:restriction>
            </xs:simpleType>
          </xs:union>
        </xs:simpleType>
      </xs:attribute>
      <xs:attribute name='cwd'>
        <xs:simpleType>
          <xs:union memberTypes="SubstitutionType">
            <xs:simpleType>
              <xs:restriction base='xs:string'>
                <xs:enumeration value='ROS_HOME'/>
                <xs:enumeration value='node'/>
              </xs:restriction>
            </xs:simpleType>
          </xs:union>
        </xs:simpleType>
      </xs:attribute>
      <xs:attribute name='launch-prefix' type='StringType'/>
      <xs:attribute name='ns' type='StringType'/>
    </xs:complexType>
  </xs:element>
  
  <xs:element name='test'>
    <xs:complexType>
      <xs:choice minOccurs='0' maxOccurs='unbounded'>
        <xs:element ref='env'/>
        <xs:element ref='remap'/>
        <xs:element ref='rosparam'/>
        <xs:element ref='param'/>
      </xs:choice>
      <xs:attribute name='if' type='StringType'/>
      <xs:attribute name='unless' type='StringType'/>
      <xs:attribute name='pkg' type='StringType' use='required'/>
      <xs:attribute name='type' type='StringType' use='required'/>
      <xs:attribute name='test-name' type='StringType' use='required'/>
      <xs:attribute name='name' type='StringType'/>
      <xs:attribute name='args' type='StringType'/>
      <xs:attribute name='clear_params' type="BoolType"/>
      <xs:attribute name='cwd'>
        <xs:simpleType>
          <xs:union memberTypes="SubstitutionType">
            <xs:simpleType>
              <xs:restriction base='xs:string'>
                <xs:enumeration value='ROS_HOME'/>
                <xs:enumeration value='node'/>
              </xs:restriction>
            </xs:simpleType>
          </xs:union>
        </xs:simpleType>
      </xs:attribute>
      <xs:attribute name='launch-prefix' type='StringType'/>
      <xs:attribute name='ns' type='StringType'/>
      <xs:attribute name='retry' type='StringType'/>
      <xs:attribute name='time-limit' type='StringType'/>
    </xs:complexType>
  </xs:element>
  
  <xs:element name='machine'>
    <xs:complexType>
      <xs:sequence minOccurs='0' maxOccurs='unbounded'>
        <xs:element ref='env'/>
      </xs:sequence>
      <xs:attribute name='if' type='StringType'/>
      <xs:attribute name='unless' type='StringType'/>
      <xs:attribute name='name' type='StringType' use='required'/>
      <xs:attribute name='address' type='StringType' use='required'/>
      <xs:attribute name='env-loader' type='StringType'/>
      <xs:attribute name='default'>
        <xs:simpleType>
          <xs:union memberTypes="BoolType">
            <xs:simpleType>
              <xs:restriction base='xs:string'>
                <xs:enumeration value='never'/>
              </xs:restriction>
            </xs:simpleType>
          </xs:union>
        </xs:simpleType>
      </xs:attribute>
      <xs:attribute name='user' type='StringType'/>
      <xs:attribute name='password' type='StringType'/>
      <xs:attribute name='timeout' type='StringType'/>
    </xs:complexType>
  </xs:element>
  
  <xs:element name='param'>
    <xs:annotation>
      <xs:documentation>
        Defines parameter to be set on the Parameter Server as given value, from textfile, binfile or command output.
        Inside of a node tag, parameter is treated as a private.
      </xs:documentation>
    </xs:annotation>
    <xs:complexType>
      <xs:attribute name='if' type='StringType'/>
      <xs:attribute name='unless' type='StringType'/>
      <xs:attribute name='name' type='StringType' use='required'/>
      <xs:attribute name='value' type='StringType'/>
      <xs:attribute name='type'>
        <xs:simpleType>
          <xs:restriction base='xs:string'>
            <xs:enumeration value='string'/>
            <xs:enumeration value='str'/>
            <xs:enumeration value='int'/>
            <xs:enumeration value='double'/>
            <xs:enumeration value='bool'/>
            <xs:enumeration value='yaml'/>
          </xs:restriction>
        </xs:simpleType>
      </xs:attribute>
      <xs:attribute name='textfile' type='StringType'/>
      <xs:attribute name='binfile' type='StringType'/>
      <xs:attribute name='command' type='StringType'/>
    </xs:complexType>
  </xs:element>
  
  <xs:element name='remap'>
    <xs:complexType>
      <xs:attribute name='if' type='StringType'/>
      <xs:attribute name='unless' type='StringType'/>
      <xs:attribute name='from' type='StringType' use='required'/>
      <xs:attribute name='to' type='StringType' use='required'/>
    </xs:complexType>
  </xs:element>
  
  <xs:element name='rosparam'>
    <xs:annotation>
      <xs:documentation>
        Enables rosparam YAML files for loading and dumping parameters to/from Parameter Server.
        Can also be used to remove parameters.
        Can either reference a YAML file or contain raw YAML text.
        If the YAML defines a dictionary, param attribute may be omitted.
      </xs:documentation>
    </xs:annotation>
    <xs:complexType mixed='true'>
      <xs:attribute name='if' type='StringType'/>
      <xs:attribute name='unless' type='StringType'/>
      <xs:attribute name='command' type='StringType'/>
      <xs:attribute name='file' type='StringType'/>
      <xs:attribute name='param' type='StringType'/>
      <xs:attribute name='ns' type='StringType'/>
      <xs:attribute name='subst_value' type="BoolType"/>
    </xs:complexType>
  </xs:element>
  
</xs:schema>

From https://gist.github.com/nalt/dfa2abc9d2e3ae4feb82ca5608090387/