gengen

README

Gengen

Gengen is a command line generics generator for the GO language suitable for use in go:generate lines. It uses standard go text templates to generate GO files that use your custom types to generate a variety of collection objects, and includes some common objects as well.

Gengen is pretty simple, and just combines a template with a json configuration file you can use to define values in the template. It expects the template to be the stdin or the only argument to the command line. Output will be directed to the file you specify with the -o option, or stdout if no file is specified.

This design means gengen does not have additional dependencies, is easily installed using go get, is cross-platform, and works well in go:generate lines.

Configuration files can contain comments at the beginning. Gengen will look for the first open bracket, and start reading its json input from there.

Installation

go get -u github.com/goradd/gengen/...

Usage

To use the command line tool to build a generic template into one specific to your types, do the following in the shell:

gengen -c <config_file>  [-o out_file] [template_file]

gengen requires the -c command to specify a json configuration file that sets up the "dot" context of the template. If you do not specify an out_file, output will be sent the StdOut. If you do not specify a template_file, the template will be read from StdIn.

File paths are module and package aware. In other words, if you do this:

gengen -c github.com/goradd/gengen/templates/map_src/safe_test.json

gengen will see the github.com/goradd/gengen as a module or package path, and substitute the real path. This works whether or not you are using modules.

Environment variables can be inserted into the path using this syntax: $var or ${var}. This works on all platforms.

Examples

See the templates/build.go file for an example of how the included library is built.

Library

Gengen includes a maintained library of templates that it uses to create some standard configurations of useful collections, and that you can use to create your own versions of those using your own types. The library includes its own generated unit test code.

License

Gengen is licensed under the MIT License.