#haredo

A simple and unix-idiomatic build automator.

#Motivation

haredo is a build automator - an alternative to e.g. make(1) and redo(1).

Problems with make:

• Hard to learn its strange syntax
• Source code is complex (~40,000 lines)
• Makefiles are frequently very bulky
• Builds that crash or are killed halfway through can produce invalid state

Problems with redo:

• Hard to learn because the commands obscure their function
• Source code is a little complex (~4,000 lines)
• Uses an external database to store dependency relations

haredo solves all of these problems:

• Script syntax is plain shell script
• Only one command with few extraneous rules
• Source code is extremely simple (~400 lines)
• .do files are short and modular like in redo
• Builds its dependency tree on the fly, uses no database
• Doesn't break the build state when interrupted

haredo additionally uses the properties of unix-like operating systems extremely idiomatically:

• processes and child processes build targets and their dependencies respectively
• environment variables are used to communicate with child builds
• exit status codes are used to communicate with the parent build
• parent directories in the file tree are used as defaults when finding .do files
• the "last-modified" timestamp on files is used to detect changes.
• shell arguments provide contextual information to .do files
• temporary files and atomic filesystem operations prevent broken builds
• uses a unix pipe as a simple jobs queue

#Process

The process for haredo boils down to this:

for each target argument:
	find and run its .do script
	if a .do script cannot be found, give a warning
return true if any of the arguments are newer than their parent, else false.

.do files are written in plain shell script, and will be run using sh -e to exit on error. The typical structure of a .do script is as follows:

# assemble the dependencies
deps="dep1 dep2"

# run the build on dependencies, and check if they are newer
if haredo $deps
then
	# build the target
fi

The above script will only build the target if the result of running haredo on its dependencies gives a truthy result -- which only happens when one of them is newer.

#Usage

haredo [-options] targets... [++ sources...]

Detailed usage information can be found in the man page.

#Installation

Requires scdoc(1) to build the man page, and a Hare install to build the executable.

git clone https://git.sr.ht/~autumnull/haredo
cd haredo
./bootstrap.sh
./bootstrap.sh install
haredo test
# haredo uninstall

#Contributing

Please send patches and bug reports to ~autumnull/haredo-devel@lists.sr.ht.

General discussion of haredo happens on ~autumnull/haredo@lists.sr.ht.