Build Systems
Build systems don't usually deal with configuration.
Make
Don't try to be clever and abstract things
Break everything into really small steps.
Make uses timestamps to work out when files are out of date.
Automatic Variables
$@ is the target.
$^ is all the dependencies.
The other automatic variables tend to make your makefile unreadable.
Zip
When unzipping things, you may need to touch the result. Alternatively, tell zip not to restore the dates.
Tup
http://gittup.org/tup/manual.html
Tup uses hashes to work out when files are out of date.
Tup removes files belonging to out of date targets.
tup graph and tup todo show useful information.
Variables
Tup supports make style variables with $(var).
Tup files
Syntax is:
# Comments
my_var="hello"
.gitignore # Generate a .gitignore for all my outputs.
input1.txt input2.txt |> ^flags run-some-command % |> output1.txt output2.txt {bin}
foreach input1.txt input2.txt |> ^flags run-some-command-on-each-file %f |> output1.txt output2.txt
Bins are a way to group outputs for use in the inputs to other
Tupfile.ini
This is a config file which follows a standard ini file format.
Monitor
Run tup monitor or tup stop.
Only works on Linux.
The Paper
Build System Rules and Abstractions
Recursive make is bad, as we know.
But, operating on the whole dependency graph at once is slow. Each time we run make, we have to check every dependency in the graph to see if changed.
We can do better by asking the file system to tell us about changes, then looking up their dependencies and marking them as dirty.