From 3fe296294d00af43a148cb6ce83193805fd9ec56 Mon Sep 17 00:00:00 2001
From: Jakob Odersky <jakob@odersky.com>
Date: Tue, 11 Dec 2018 18:58:55 -0800
Subject: Initial commit

---
 README.md | 98 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 README.md

(limited to 'README.md')

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..c052c12
--- /dev/null
+++ b/README.md
@@ -0,0 +1,98 @@
+# A makefile for Scala Applications
+
+A makefile that demonstrates how building Scala applications can be
+very simple.
+
+It supports *dependency resolution of maven artefacts*, enables
+building *executables* (not only fat jars, actual executable files)
+and all **builds are reproducible** (anyone building the same source
+gets bit-wise identical binaries).
+
+## Dependencies
+
+As this is a plain makefile, it relies on a number of tools that must
+be present in the caller's environment. Those are:
+
+- [scalac](https://www.scala-lang.org/download/) to compile Scala
+- [coursier](https://coursier.github.io/coursier/1.1.0-SNAPSHOT/docs/quick-start-cli.html#installation) for dependency resolution
+- openjdk to run binaries and for packaging jar files
+- zip and unzip for creating standalone fat jars
+- (optional) [scalafmt](https://scalameta.org/scalafmt/docs/installation.html#cli)
+
+Tested on Linux, should work on Darwin and BSDs, does not support
+Windows.
+
+## How-To
+
+Source files are in `src/` and maven dependencies are declared in
+`Maven.list`.
+
+The main targets for a development workflow are typically
+
+- `make` to build a library jar in target/library.jar
+- `make run` to run the application 
+
+The application may be deployed as a standalone binary, only requiring
+a Java runtime environemnt, by running `make target/application`.
+
+## Example
+
+This project contains an example application that prints the identicon
+of a given string. Build it by running `make target/application`.
+
+- Generate an identicon: `target/application username`.
+- View an identicon: `inkview <(target/application admin)`.
+
+## Known Issues / FAQ
+
+- **It's slow**. Yes, this Makefile invokes a cold compiler on every
+  source change. Using [bloop](https://scalacenter.github.io/bloop/)
+  could help here.
+  
+- **Tools not included**. To run this makefile, all its constituent
+  tools (scalac, scalafmt, coursier, etc) must be configured in the
+  developer's environment. It's not as convenient for newcomers as the
+  out-of-the-box experience that sbt or cbt offer, however adhering to
+  the unix philosophy of "do one thing and do it well" is the whole
+  purpose of this project.
+
+- **Doesn't work with multiple Akka libraries**. The jar combination
+  script is quite dumb: it simply extracts contents of jar files in a
+  directory tree and recombines the final directory into a jar. In the
+  process, any identically named files get overwritten. Since Akka
+  relies on `reference.conf` files within jars, if multiple Akka
+  libraries are used, the latest config in the classpath overwrites
+  all others. A smarter merging script would be required to fix tis
+  issue.
+
+- **The resulting binary is large**. The fat jar which is contained in
+  the application contains *all* dependent jars, which may add up for
+  projects with complex transitive dependencies. Using a tool like
+  proguard could drastically decrease the size of the final binary.
+
+- **The resulting binary requires a Java runtime**. See
+  [scala-native](http://www.scala-native.org/en/v0.3.8/), in the
+  future hopefully we can add support for it in the form of an
+  independent makefile.
+  
+- **Should I use this?** Maybe. This project was intended as a
+  proof-of-concept; it was motivated by my feeling that build tools in
+  the Scala world tend to be very complex machines, and that using
+  them to their full extent requires almost as much effort as learning
+  a new language.
+  
+  My suggestion is that you should give this Makefile a shot if
+  
+  1. You are new to Scala but familiar with programming and the unix
+     environment, and want a quick but thorough overview of the steps
+     involved in going from a source file to an executable.
+ 
+  2. You are building an **application**. This makefile is too
+     bare-bones for libraries (for example it does not support
+     multiple scala version or uploading to Maven Central).
+
+  3. You agree with the following sentiment, as
+     [cbt](https://github.com/cvogt/cbt/)'s author, Chris Vogt, puts
+     it:
+
+	> Do you own your Build Tool or does your Build Tool own you?
-- 
cgit v1.2.3