Contribute to DAX Lib

A DAX library is deployed as a package in DAX Lib. A package is a ZIP file that includes a few files (TODO add package description).

You can follow these steps to add a new package to DAX Lib:

1. Clone the GitHub repository https://github.com/sql-bi/daxlib/.

2. Create a folder for your package in /packages/, for example by copying the DaxLib.Sample package.

   a. Name the folder after your package using lowercase names (e.g., test.functions), while the package should have a pascal naming convention (e.g., Test.Functions).

   b. The package and library name is the prefix of all the function names. For example, to functions Sum and Multiply in the Test.Functions library package should be named Test.Functions.Sum and Test.Functions.Multiply.

   c. The package and library name must have a hierarchical nomenclature, where the first name is the published/author identifier and the second (and following) names identify the library scope. For example, Contoso.Conversion is a library of conversion functions made by Contoso, whereas Northwind.Math.Geometry is a set of geometrical mathematical functions made by Northwind.

   d. Do not use Dax. in the name of the library (Dax as a single word is a reserved keyword in a function name).

   e. DaxLib. as a prefix is a reserved word for public open-source libraries of common use that are reviewed and approved by DaxLib maintainers. Do not create pull request for new DaxLib. libraries.

   f. The first level in the folder structure is a single letter corresponding to the first letter of the package name (for example, a package test.functions will be in /packages/t/test.functions/ folder). This is a technique used to reduce the number of elements in a single folder.

   g. All the names of folders and files must be lowercase; the name of the package (with uppercase letters if necessary) is defined in the metadata (manifest.daxlib file) of the package.

3. Create the DAX functions in functions.tmdl

   a. The file lib/functions.tmdl contains the source code of the DAX functions in a TMDL createOrReplace command. For example, in test.functions the name is /packages/t/test.functions/lib/functions.tmdl

   b. The functions.tmdl file contains the function definition using the TMDL syntax following the createOrReplace statement

   c. Include mandatory annotations for each function of the library:

   ```
   annotation DAXLIB_PackageId = <name of library>
   annotation DAXLIB_PackageVersion = <version of library>
   ```
   

4. Create the manifest in the manifest.daxlib file

   a. For example, in test.functions the name is /packages/t/test.functions/manifest.daxlib

   b. The manifest.daxlib file contains the package properties in JSON format. See the DaxLib.Sample package for an example and refer to the JSON schema for the complete specification of available properties.

5. Create a pull request to publish the library on daxlib.org

   a. The pull request must be approved manually by DaxLib owners/maintainers.

   b. When the pull request is approved, the package is immediately published.