Working with the Standard Library

Jayvee ships with its own standard library on board, including the most often used valuetypes, transformations, and so on. The standard library itself is written in .jv files here.

Standard Library Contents

The following elements are part of the standard library:

Builtin Contents

The implementations of builtin contents are not expressed in Jayvee itself but on the TypeScript layer. Examples:

• Builtin valuetypes: These valuetypes are the base for defining user-defined valuetypes in Jayvee, e.g., text, integer, decimal, boolean.
• Builtin iotypes: These iotypes are used to describe in inputs and outputs of blocktypes, e.g., Sheet, File.
• Builtin blocktypes: These blocktypes are the very basic building blocks in Jayvee, e.g., HttpExtractor, SqliteLoader.

Builtin definitions are usually generated and added to the standard library from the internal representations of the concepts.

User-defined Contents

The implementations of user-defined contents are expressed in Jayvee itself. Examples:

• User-defined valuetypes: These valuetypes are based on builtin or other user-defined valuetypes. Their definition is expressed natively in Jayvee, e.g., Percent.
• User-defined blocktypes: These blocktypes are based on builtin or other user-defined blocktypes. Their definition is expressed natively in Jayvee.

We use jv files to add user-defined valuetypes to the standard library (see below).

Extending the Standard Library

Just add jv files to the directory here. It is crawled hierarchically, meaning that you can also organize files in folders.

Implementation

1. Code generation

We use code generation to transform these .jv files into TypeScript files that the language server can used. The generation script is run via npm run generate next to the AST generation.

2. Builtin libraries

The solution we chose to implement the standard library mechanism is close to the builtin library tutorial by Langium. The following components are of interest:

• JayveeWorkspaceManager in the language-server that registers all libraries with the langium framework.
• StandardLibraryFileSystemProvider in the vs-code-extension that registers all libraries with the vscode plugin framework.