352 lines
11 KiB
Markdown
352 lines
11 KiB
Markdown
# ackbuilder
|
|
|
|
## What is it?
|
|
|
|
ackbuilder is a very small build tool inspired by [bazel](https://bazel.io/)
|
|
which uses either make or [ninja](https://ninja-build.org/) as a backend.
|
|
|
|
It supports fully parallelisable builds (in both make and ninja), as well as
|
|
hopefully-robust support for rules which generate more than one output file,
|
|
which is something make is very, very bad at.
|
|
|
|
It was written because the ACK is a really horribly complex thing to build and
|
|
there wasn't anything else. ackbuilder is pretty rough and ready but it does
|
|
sort of work. Be prepared for bugs.
|
|
|
|
This document is a very rapid brain dump of how the build file works. It
|
|
doesn't cover actually running the tool (because that bit's pretty nasty) ---
|
|
go look at the top level Makefile to see that for now.
|
|
|
|
## Basic concepts
|
|
|
|
Complete example, using the built-in C rules. This should be saved in a file
|
|
called `build.lua`:
|
|
|
|
cprogram {
|
|
name = 'prog',
|
|
srcs = { "./*.c" },
|
|
}
|
|
|
|
This defines a rule `prog` which, when built, compiles all the source files in
|
|
the same directory as the `build.lua` file into an executable.
|
|
|
|
Slightly more complex example:
|
|
|
|
clibrary {
|
|
name = "library",
|
|
srcs = { "./library.c" },
|
|
hdrs = { "./library.h" },
|
|
}
|
|
|
|
cprogram {
|
|
name = 'prog2',
|
|
srcs = { "./prog2.c" },
|
|
deps = { "+library" }
|
|
}
|
|
|
|
If we move the library into another directory, we can invoke it like this:
|
|
|
|
cprogram {
|
|
name = 'prog3',
|
|
srcs = { "./prog3.c" },
|
|
deps = { "path/to/library+library" }
|
|
}
|
|
|
|
* Targets starting with `./` are relative to **the current directory** (i.e.
|
|
the one the build file is in).
|
|
|
|
* Targets starting with a path are relative to the top directory of the
|
|
project.
|
|
|
|
* Targets containing a `+` refer to a named target in another build file. So,
|
|
on encountering the library in `prog3` above, ackbuilder will look for
|
|
`path/to/library/build.lua`, load it, and then try to find a target in it
|
|
called `library`.
|
|
|
|
**Warning**: files are interpreted from top to bottom; every time a target
|
|
referring to another build file is seen for the first time, that file is
|
|
interpreted then and there. You can't have circular dependencies (these are
|
|
caught and an error is generated). You can't refer to a target defined below
|
|
you in the same source file (these are not caught, and just won't be found).
|
|
|
|
Build files each get their own private global scope. If you randomly set a
|
|
variable, it won't be seen by other build files. (Use `vars` for that; see
|
|
below.) Build files are only loaded once.
|
|
|
|
The `cprogram` and `clibrary` rules, by the way, are sophisticated enough to
|
|
automatically handle library and header paths. The exported headers by the
|
|
library are automatically imported into the program.
|
|
|
|
## `simplerule` and `normalrule`
|
|
|
|
These are the building blocks out of which all other rules are made. If you
|
|
want to run your own programs, you will be using these.
|
|
|
|
`simplerule` is the simplest. You give it inputs, and outputs, and commands,
|
|
and it does it.
|
|
|
|
simplerule {
|
|
name = 'sorted-input',
|
|
ins = { './input.txt' },
|
|
outs = { './output.txt' },
|
|
commands = {
|
|
"sort < %{ins} > %{outs}"
|
|
}
|
|
}
|
|
|
|
In a command block, `%{...}` will evaluate the Lua expression between the
|
|
braces; various useful things are in scope, including the list of inputs and
|
|
outputs.
|
|
|
|
However, this ends up leaving the output file lying around in the project
|
|
directory, which we don't want, so we usually use `normalrule` instead.
|
|
(`normalrule` is not strictly part of the ackbuilder core; it's in the standard
|
|
library along with `cprogram` and `clibrary`.)
|
|
|
|
normalrule {
|
|
name = 'sorted-input',
|
|
ins = { './input.txt' },
|
|
outleaves = { 'output.txt' },
|
|
commands = {
|
|
"sort < %{ins} > %{outs}"
|
|
}
|
|
}
|
|
|
|
Note `outleaves`; there is no `./`. This is a list of leaf filenames. The rule
|
|
will create a directory in the object tree and put the files specified in it,
|
|
somewhere; you don't care where. You can refer to the output file via the
|
|
target name, so:
|
|
|
|
normalrule {
|
|
name = 'reversed',
|
|
ins = { '+sorted-input' },
|
|
outleaves = { 'reversed.txt' },
|
|
commands = {
|
|
"rev < %{ins} > %{outs}"
|
|
}
|
|
}
|
|
|
|
One common use for this is to generate C header or source files.
|
|
|
|
normalrule {
|
|
name = 'reversed_h',
|
|
ins = { '+reversed' },
|
|
outleaves = { 'reversed.h' },
|
|
commands = {
|
|
'xxd -i %{ins} > %{outs}'
|
|
}
|
|
}
|
|
|
|
cprogram {
|
|
name = 'prog',
|
|
srcs = { './*.c' },
|
|
deps = { '+reversed_h' }
|
|
}
|
|
|
|
Now you can refer to `reversed.h` in one of your C files and it'll just work
|
|
(`+reversed_h`'s output directory gets added to the include path
|
|
automatically).
|
|
|
|
## Defining your own rules
|
|
|
|
Like this:
|
|
|
|
definerule("sort",
|
|
{
|
|
srcs = { type="targets" },
|
|
},
|
|
function(e)
|
|
return normalrule {
|
|
name = e.name,
|
|
ins = e.srcs,
|
|
outleaves = { 'sorted.txt' },
|
|
commands = {
|
|
"sort < %{ins} > %{outs}"
|
|
}
|
|
}
|
|
}
|
|
)
|
|
|
|
sort {
|
|
name = 'sorted',
|
|
srcs = { './input.txt' }
|
|
}
|
|
|
|
You give `definerule()` the name of the rule you want to define, a description
|
|
of the properties the rule will take, and a callback that does the work.
|
|
|
|
You can do anything you like in the callback, including defining as many
|
|
targets as you like; but remember that all targets must have unique names, so
|
|
for any temporary files you probably want something like `name =
|
|
e.name.."/intermediate"` to ensure uniqueness.
|
|
|
|
The callback should end by returning an invocation of another rule, with `name
|
|
= e.name` as above.
|
|
|
|
Rules are defined whenever a build file containing them is seen. Letting this
|
|
happen automatically doesn't always work so you probably want to explicitly
|
|
include it:
|
|
|
|
include("foo/bar/baz/build.lua")
|
|
|
|
Rule properties are typed and can be specified to be required or optional (or
|
|
have a default value). If you try to invoke a rule with a property which isn't
|
|
declared, or missing a property which should be declared, you'll get an error.
|
|
|
|
definerule("sort",
|
|
{
|
|
srcs = { type="targets" },
|
|
numeric = { type="boolean", optional=true, default=false }
|
|
}
|
|
...omitted...
|
|
|
|
(The `optional=true` part can be omitted if you specify a default which isn't
|
|
`nil`.)
|
|
|
|
Types include:
|
|
|
|
* `targets`: the most common one. When the rule is invoked, ackbuilder will
|
|
resolve these for you so that when your callback fires, the property is a
|
|
flattened list of target objects.
|
|
|
|
* `strings`: a Lua table of strings. If the invoker supplies a single string
|
|
which isn't a table, it'll get wrapped in one.
|
|
|
|
* `string`: a string.
|
|
|
|
* `boolean`: a boolean (either `true` or `false`; nothing else is allowed).
|
|
|
|
* `table`: a Lua table.
|
|
|
|
* `object`: any Lua value.
|
|
|
|
## Target objects
|
|
|
|
When a rule callback is run, any targets it needs will be resolved into target
|
|
objects. These are Lua objects with assorted useful stuff in them.
|
|
|
|
* `object.is`: contains a set telling you which rules made the object. e.g.
|
|
`object.is.cprogram` is true if `object` was built with `cprogram`. Bear in
|
|
mind that `object.is.normalrule` is _also_ going to be true.
|
|
|
|
* `object.dir`: the object's build directory. Only exists if the object was
|
|
built with `normalrule`.
|
|
|
|
There are other properties (`fullname` and `outs`). Please don't use these; use
|
|
`targetnamesof()` and `filenamesof()` as described below.
|
|
|
|
## The standard library
|
|
|
|
Your build files are supplied a pile of useful functions.
|
|
|
|
### Manipulating target lists
|
|
|
|
A target list is a possibly nested set of tables containing either target
|
|
objects or strings. All of these functions will implicitly flatten the list and
|
|
resolve any strings into target objects before doing anything else to them.
|
|
Most of these functions can be supplied with varargs parameters.
|
|
|
|
e.g. `targetsof(a, b)` is equivalent to `targetsof({a, b})` is equivalent to
|
|
`targetsof({a, {b}})`.
|
|
|
|
* `targetsof(...)`: just flattens the list and resolves any string target
|
|
names.
|
|
|
|
* `filenamesof(...)`: returns a list of output files for all the supplied
|
|
targets.
|
|
|
|
* `targetnamesof(...)`: returns a list of fully qualified target names for
|
|
all the supplied stargets.
|
|
|
|
* `selectof(targets, pattern)`: returns only those targets whose outputs
|
|
contain at least one file matching the pattern.
|
|
|
|
### Manipulating filename lists
|
|
|
|
Like the target list functions, all of these implicitly flatten any nested
|
|
tables. They all return lists; however, as a special exception, if any of the
|
|
functions which take varargs parameters have a single parameter which is a
|
|
string, they return just a string.
|
|
|
|
e.g. `abspath({f})` returns a table; `abspath(f)` returns a string.
|
|
|
|
* `abspath(...)`: attempts to return the absolute path of its arguments. This
|
|
isn't always possible due to variable references.
|
|
|
|
* `basename(...)`: returns the basenames of its arguments (the file part of
|
|
the path).
|
|
|
|
* `dirname(...)`: returns the directory name of its arguments.
|
|
|
|
* `matching(files, pattern)`: returns only those files which match a Lua
|
|
pattern.
|
|
|
|
* `replace(files, pattern, repl)`: performs a Lua pattern replace on the list
|
|
of files.
|
|
|
|
* `uniquify(...)`: removes duplicates.
|
|
|
|
### Other things
|
|
|
|
* `include(file)`: loads another build file, if it hasn't been loaded before.
|
|
|
|
## Variables
|
|
|
|
There are two types of variable, mostly for hysterical reasons.
|
|
|
|
### Makefile variables
|
|
|
|
(Despite the name, these work on ninja too.)
|
|
|
|
Filenames can contain variable references of the form `$(FOO)`. These are
|
|
expanded at build time based on definitions supplied on the ackbuilder command
|
|
line.
|
|
|
|
ackbuilder assumes that these are absolute paths and won't attempt to
|
|
manipulate them much.
|
|
|
|
I want to get rid of these at some point.
|
|
|
|
### ackbuilder variables
|
|
|
|
These are expanded by ackbuilder itself.
|
|
|
|
Every rule invocation contains a magic property, `vars`. When a rule's commands
|
|
are executed, the variables provided in the template expansion are calculated
|
|
by combining all `vars` settings in the call stack (including the top level
|
|
build file).
|
|
|
|
Easiest to explain with an example:
|
|
|
|
cprogram {
|
|
name = 'another_test',
|
|
srcs = { './*.c' },
|
|
vars = {
|
|
cflags = { '-g', '-O3' }
|
|
}
|
|
}
|
|
|
|
When `cprogram` builds each C file, the command will refer to `%{cflags}`. The
|
|
value above will be flattened into a space-separated string and substituted in.
|
|
|
|
Setting a variable this way will _override_ any definition further up the call
|
|
stack. However, you can do this:
|
|
|
|
vars.cflags = { '-g' }
|
|
|
|
cprogram {
|
|
name = 'another_test',
|
|
srcs = { './*.c' },
|
|
vars = {
|
|
["+cflags"] = { '-O3' }
|
|
}
|
|
}
|
|
|
|
Now `cflags` will default to `-g` everywhere, because it's set at the top
|
|
level; but when `another_test` is built, it'll be `-g -O3`.
|
|
|
|
ackbuilder variables are only expanded in command templates, not in filenames.
|
|
|
|
<!-- # vim: set ts=2 sw=2 expandtab : -->
|
|
|