Add README and code comments

README.md

@@ -0,0 +1,70 @@
+# Poly CLI
+
+[What is Poly?](https://polygui.org)
+
+This CLI provides commands to create and manage Poly projects. It is the official way to get started with creating Poly
+applications.
+
+## Installation
+
+The CLI is available as pre-built binaries on the [GitHub Releases page](https://github.com/poly-gui/cli/releases).
+
+### Building The CLI
+
+The CLI can also be built from the source code, which requires:
+
+- [Go >= 1.20](https://go.dev/dl/)
+
+First, clone this repo:
+
+```
+git clone https://github.com/poly-gui/cli.git
+```
+
+This clones the repo into a directory called "cli". If the name is too generic, feel free to clone the repo into a
+directory with a different name.
+
+Change into the repo, then build and install the binary:
+
+```
+go install poly-cli/cmd/poly
+```
+
+The `poly` command should now be installed and ready to use. Make sure `GOBIN`
+is in PATH, which defaults to `$(go env GOPATH)/bin`. If not, add:
+
+```
+export PATH="$PATH:$(go env GOPATH)/bin"
+```
+
+or if `GOBIN` is set:
+
+```
+export PATH="$PATH:$(go env GOBIN)/bin"
+```
+
+to your path.
+
+For more information on `GOPATH` and `GOBIN`, please consult
+the [official documentation](https://go.dev/doc/install/source#gopath).
+
+## Usage
+
+### ```poly generate```
+
+The `generate` command creates a new Poly project directory in the current working directory by default. The following
+flags are available:
+
+|    Flags    |                                                                      Description                                                                      |
+|:-----------:|:-----------------------------------------------------------------------------------------------------------------------------------------------------:|
+| `--output`  |                      The directory in which the project directory should be created. Defaults to the current working directory.                       |
+|  `--name`   |                                                  The name of the application. Defaults to "PolyApp"                                                   |
+| `--package` | The package name/bundle identifier/application ID of the application. This typically uses the reverse domain name notation. Defaults to "org.polygui" |
+
+### Examples
+
+```
+poly generate --name=MyNewApp --package=org.my
+```
+
+This generates a new Poly app called "MyNewApp" that has "org.my" as the package identifier. A "MyNewApp" directory is created in the current working directory.

internal/cli/doc.go

@@ -0,0 +1,2 @@
+// Package cli contains the main logic of the CLI.
+package cli

internal/cli/generate.go

@@ -13,6 +13,7 @@ import (
 	"sync"
 )
 
+// Generate is run when `poly generate` is invoked.
 func Generate() error {
 	os.Args = append(os.Args[:1], os.Args[2:]...)
 

internal/template/appkit.go

@@ -2,6 +2,7 @@ package template
 
 import "path/filepath"
 
+// AppKitSourceFiles is a list of templates of files that will be in the "macOS" directory in a Poly project.
 var AppKitSourceFiles = []templateFile{XcodeGenSpec, SwiftMainFile, AppDelegate}
 
 var XcodeGenSpec = templateFile{

internal/template/gtk.go

@@ -2,6 +2,7 @@ package template
 
 import "path/filepath"
 
+// GTKSourceFiles is a list of templates of files that will be in the "gtk" directory in a Poly project.
 var GTKSourceFiles = []templateFile{GTKCMakeLists, GTKCxxMainFile, GTKLaunchScript, GTKRPMSpec}
 
 var GTKCMakeLists = templateFile{

internal/template/template.go

@@ -11,6 +11,7 @@ import (
 	gotemplate "text/template"
 )
 
+// templateFile describes the template for a file that is generated during the creation of a new Poly project.
 type templateFile struct {
 	// FilePathRel is the path to the output file relative to the native source code directory such as <project>/macOS or <project>/gtk.
 	// Use _APP_NAME_ as a placeholder for the app name if needed.
@@ -24,6 +25,7 @@ type templateFile struct {
 	TemplateName string
 }
 
+// funcMap defines functions that are usable in templateFile.template.
 var funcMap = gotemplate.FuncMap{
 	"ToKebab": strcase.ToKebab,
 }

internal/template/ts_source.go

@@ -2,6 +2,8 @@ package template
 
 import "path/filepath"
 
+// TSSourceFiles is a list of templates of files that will be in the "app" folder of a Poly project
+// if TypeScript is used as the language of choice for the portable layer.
 var TSSourceFiles = []templateFile{TSConfigJSON, PackageJSON, TSGitIgnore, TSMainFile}
 
 var TSConfigJSON = templateFile{