Provide a Makefile for integration in pret-based projects as a submodule (#80)

* Provide a Makefile for integration in pret-based projects as a submodule

Fixes: #78

* Override `TARGET` for native-Windows

Co-authored-by: Marcus Huderle <huderlem@gmail.com>

Author: lhearachel

Makefile

@@ -0,0 +1,24 @@
+# Makefile for use as a subproject of pokeemerald, et al
+# The enforced contract is to provide a default target to compile the tool and a
+# "clean" target to sweep everything up
+
+.PHONY: all clean
+
+TARGET := poryscript
+ifeq ($(OS),Windows_NT)
+    TARGET := $(TARGET).exe
+endif
+
+# Add any new packages to this variable to pick up underlying source files
+PACKAGES := ast emitter lexer parser
+GOFILES  := main.go $(foreach package,$(PACKAGES),$(wildcard $(package)/*.go))
+SOURCES  := $(filter-out %_test.go,$(GOFILES))
+
+$(TARGET): $(SOURCES)
+	go build -o $@
+
+all: $(TARGET)
+
+clean:
+	go clean
+	rm -f $(TARGET)

README.md

@@ -15,6 +15,8 @@ View the [Changelog](https://github.com/huderlem/poryscript/blob/master/CHANGELO
 
 **Table of Contents**
 - [Usage](#usage)
+  * [Basic Installation](#basic-installation)
+  * [Install as a Git Submodule](#install-as-a-git-submodule)
   * [Convert Existing Scripts](#convert-existing-scripts)
   * [Using Poryscript in Your Favorite IDE or Text Editor](#extensions)
 - [Poryscript Syntax (How to Write Scripts)](#poryscript-syntax-how-to-write-scripts)
@@ -81,6 +83,7 @@ Convert a `.pory` script to a compiled `.inc` script, which can be directly incl
 ./poryscript -i data/scripts/myscript.pory -o data/scripts/myscript.inc
 ```
 
+## Basic Installation
 To automatically convert your Poryscript scripts when compiling a decomp project, perform these two steps:
 1. Create a new `tools/poryscript/` directory, and add the `poryscript` command-line executable tool to it. Also copy `command_config.json` and `font_config.json` to the same location.
 ```
@@ -117,6 +120,60 @@ generated: $(AUTO_GEN_TARGETS)
 + data/%.inc: data/%.pory; $(SCRIPT) -i $< -o $@ -fc tools/poryscript/font_config.json -cc tools/poryscript/command_config.json
 ```
 
+## Install as a Git Submodule
+Users may wish to install Poryscript as a dependency of their project if they work with other collaborators and require all contributors to use the same version. To accomplish this, we can integrate the tool as a [Git submodule](https://git-scm.com/book/en/v2/Git-Tools-Submodules). This has an additional benefit of automatically rebuilding Poryscript from source when bumping to a new version.
+
+1. Initialize the Git submodule. If you use a fork of Poryscript to implement custom features, replace the `https://github.com/huderlem/poryscript` URL with the appropriate URL for your fork.
+
+```bash
+cd path/to/your/pokeemerald
+git submodule add https://github.com/huderlem/poryscript tools/poryscript
+```
+
+2. Pin your submodule to the latest release (or to your desired target version, if they differ).
+
+```bash
+cd tools/poryscript
+git checkout 3.5.2
+cd -
+git add tools/poryscript
+```
+
+3. Make the following changes to `make_tools.mk`:
+
+```diff
+- TOOL_NAMES := aif2pcm bin2c gbafix gbagfx jsonproc mapjson mid2agb preproc ramscrgen rsfont scaninc
++ TOOL_NAMES := aif2pcm bin2c gbafix gbagfx jsonproc mapjson mid2agb preproc ramscrgen rsfont scaninc poryscript
+```
+
+4. Make the changes to `Makefile` as described above in [Basic Installation](#basic-installation).
+
+5. Commit your changes and push to the remote.
+
+This installation method necessitates some changes in your project's workflow. When cloning your project to a fresh local copy, you should specify the `--recursive` option, which will ensure that Poryscript is checked out alongside your repository:
+
+```bash
+git clone --recursive https://github.com/YOUR_USERNAME/pokeemerald.git
+```
+
+After receiving the updates to integrate the submodule, existing local copies of the repository must do the following:
+
+```bash
+git submodule update --init
+```
+
+Finally, if/when new changes are pushed to Poryscript that you wish to receive, update the submodule like you would any other Git repository:
+
+```bash
+cd tools/poryscript
+git fetch
+git checkout REF # REF can be a version tag, a branch, or a commit hash
+cd -
+git add tools/poryscript
+git commit
+git push
+```
+
 ## Convert Existing Scripts
 If you're working on a large project, you may want to convert all of the existing `scripts.inc` files to their `scripts.pory` equivalents. Since there are a large number of script files in the Gen 3 projects, you can save yourself a lot of time by following these instructions. **Again, this is completely optional, and you would only want to perform this bulk conversion if you're emabarking on large project where it would be useful to have all the existing scripts setup as Poryscript files.**