Node CLI for General Language Syntax (GLS).
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Node CLI for General Language Syntax (GLS).


npm install general-language-syntax gls-cli ts-gls typescript gls-cli --global

gls --help

Pass any number of filenames and/or globs (matched with glob) to the CLI to convert those files to an output -l/--language.

Input files to convert from GLS to the output language must have a .gls extension.

.ts files may also be given with -t/--tsconfig to compile to .gls files before output language conversion.

Option Purpose
-e/--exclude Glob(s) of file(s) to exclude from conversion.
-l/--language Output language to convert to.
-n/--namespace Namespace before path names, such as "Gls".
-p/--project Path to a gls.json project file to indicate to create project root-level exports and metadata files. Will default to a gls.json file detected in the current directory if one exists and -p/--project is not provided as false.
-t/--tsconfig TypeScript project configuration file. (Required if .ts file(s) given)
-v/--version Prints the GLS, GLS-CLI, and TS-GLS versions.

Example Usage

To convert file.gls to

gls --language Python file.gls

To convert *.ts to *.gls, then to *.java:

gls --language Java --tsconfig ./tsconfig *.ts

Requires Node >=8


To build from scratch, install Node.js and run the following commands:

npm install
npm install general-language-syntax ts-gls typescript --no-save
npm run verify

Check package.json for the full list of commands. To set up source file compiling in watch mode, use tsc -w.


Run tsc -p test to build tests, or tsc -p test -w to rebuild the files in watch mode. Run npm run test:run to run tests.


When the CLI is called, the following code paths are used in order:

  1. Cli
  2. Main
  3. Preprocessing
  4. Conversions
  5. Postprocessing


Parses raw string arguments using commander. If the args are valid, it calls to the Main method.

System dependencies such as the IFileSystem and globber may be dependency-injected to override the defaults.

See cli.ts.


Validates GLS settings, sets up the conversion's Preprocess, Runner, and Postprocess, then runs them in that order. There are two real behaviors here not covered by the Cli:

  • Globbing file paths passed as glob args and reading them the file system.
  • Validating the provided language is known by GLS.

See main.ts.


If any files are passed in with native language extensions, namely .ts for TypeScript, they are converted here using that langauge's converter to their .gls equivalent.

For example, if a .ts file is provided, it will attempt to convert it using TS-GLS and return the generated .gls file path. If a .gls file path is provided, it will do nothing and pass that path through.

Any language-specific files that are used as metadata files for that language, such as src/index.js for JavaScript, will be removed from the files list.

See preprocessFiles.ts.


Converts each .gls file to the output language(s).

convertFiles uses an async queue to throttle the number of files that are attempted to be converted via convertFile at once, as some conversions may need asynchronous operations. Creates a GlsConverter per output language and has each file run through them.

See convertFiles.ts and convertFile.ts.


Runs tasks on the converted .gls files as a project group after they've been successfully created.

If a .gls.json is not provided or detected, this does nothing. Otherwise, it creates a root metadata file(s) as specified by each output language. These are typically one or both of:

  • Metadata file describing the output project.
  • Exports file exporting publicaly exportable objects for languages that need them.

See postprocess.ts.