Simplified Syntax

To avoid verbose step definitions, a simplified syntax allows to reduce boilerplate for common operations.

Step definitions are based on the code ontology and include details necessary to locate, load and call the implementation code. For example, the following snippet (already described in greater detail in the pipeline concepts page) allows to load and call a node library function.

<#readFile> a p:Step ;
  code:implementedBy [ a code:EcmaScriptModule ;
    code:link <node:fs#createReadStream>
  ] ;
  code:arguments ( "input.txt" ) .

The above step definition would likely be used in the step list of a pipeline:

<#pipeline> a p:Pipeline ;
  p:steps [
    p:stepList ( 
      <#readFile> 
      <#doSomethingElse> 
    )
  ] .

The barnard59-core package already defines the createReadStream operation in its manifest:

@base <http://barnard59.zazuko.com/operations/core/> .

<fs/createReadStream> a p:Operation, p:Readable;
  rdfs:label "Read file";
  rdfs:comment "Reads a file from the local file system.";
  code:implementedBy [ a code:EcmaScriptModule;
    code:link <node:fs#createReadStream>
  ].

Hence, we can inline the call to such a well-known operation:

@prefix fs: <http://barnard59.zazuko.com/operations/core/fs/> .

<#pipeline> a p:Pipeline ;
  p:steps [
    p:stepList ( 
      [ fs:createReadStream ( "input.txt" ) ]
      <#doSomethingElse> 
    )
  ] .

As you can see, an step declared in simplified syntax is a node with a single predicate which is the operation's identifier. Arguments are passed as usual. As a list, if the operation uses positional parameters, or key/value pairs, if the operation has named parameters. See this page for more details.

Other examples of simplified syntax are in the getting started tutorial.

Each barnard59 package listed in the operations page has a manifest.ttl file with the available operations. Frequently used ones are in the manifests of barnard59-base and barnard59-formats.

Once imported in a project, the barnard59 CLI will find the manifest in the node_modules directory, enabling the use of simplified syntax for the operations found.