Lake is a GNU make or Ruby's rake like build utility in Common Lisp. Instead of Makefile or Rakefile, it uses Lakefile where tasks executed are defined.

Make is, originally, a program to build executable files to compile multiple source files and resolve their dependency, however its use case may not be limited as a build utility but shell command management is also good. Lake's main use case would be the latter.

In lake, you use Lakefile instead of Makefile or Rakefile.

;; Tasks that build an executable with dependency.
(defparameter cc (getenv "CC" "gcc"))

(file "hello" ("hello.o" "message.o")
  (sh #?"${cc} -o hello hello.o message.o"))

(file "hello.o" ("hello.c")
  (sh #?"${cc} -c hello.c"))

(file "message.o" ("message.c")
  (sh #?"${cc} -c message.c"))

(task "clean" ()
  (sh "rm -rf hello hello.o message.o"))

From REPL, you can call hello task with the following form. Ensure that the REPL process' current directory is same as the Lakefile.

(lake:lake :target "hello")

Or you can also call it from command line, which would be the main use case of lake.

$ lake hello

As a tip, you can generate an empty Lakefile with package related boilerplates in the current directory as:

$ lake-tools init

Further detail, please see Lakefile section and API section.

brew tap takagi/lake https://github.com/takagi/lake
brew install lake

(ql:quickload :lake)

Also you can install it using Roswell including lake command. Ensure that PATH environment variable contains ~/.roswell/bin.

$ ros install lake
$ which lake
/path/to/home/.roswell/bin/lake

Lake provides the following forms to define tasks and namespaces in Lakefile:

• Task is the fundamental concept processing a sequence of shell commands
• File Task is a task resolving file dependency with up-to-date check
• Directory Task is a task that ensures a directory exists.
• Namespace is for grouping up multiple tasks to magage them.

TASK task-name dependency-list [description] form*

task represents a sequence of operations to accomplish some task. task-name is a string that specifies the target task by its name. dependency-list is a list of task names on which the target task depends. The dependency task names are given in both relative and absolute manner, which begins with a colon :. description is a doc string. forms can be any Common Lisp forms.

$ cat Lakefile
...
(namespace "hello"

  (task "foo" ("bar")               ; dependency task in relative manner
    (echo "hello.foo"))

  (task "bar" (":hello:baz")        ; dependency task in absolute manner
    (echo "hello.bar"))

  (task "baz" ()
    (echo "hello.baz")))

$ lake hello:foo
hello.foo
hello.bar
hello.baz

FILE file-name dependency-list [description] form*

file task represents a sequence of operations as well as task except that it is executed only when the target file is out of date. file-name is a string that specifies the target file's name. dependency-list is a list of tasks or file names on which the target file depends. The dependency task/file names are given in both relative and absolute manner, which begins with a colon :. description is a doc string. forms can be any Common Lisp forms.

$ cat Lakefile
...
(file "hello" ("hello.c")
  "Compile hello from C source code."
  (sh "gcc -o hello hello.c"))

$ lake hello
$ ls
Lakefile hello hello.c

DIRECTORY directory-name [description]

directory task represents a task that ensures a directory with name of directory-name exists. description is a doc string. directory task does not depend on other tasks.

$ cat Lakefile
...
(directory "dir")

$ lake dir
$ ls
Lakefile dir

NAMESPACE namespace form*

namespace groups up multiple tasks for ease of their management. namespace is a string that specifies the namespace. Tasks in a namespace are refered with the namespace as prefix separated with a colon :. Namespaces may be recursive.

$ cat Lake
...
(namespace "foo"
  (namespace "bar"
    (task "baz" ()
      (echo "foo.bar.baz")))))

$ lake foo:bar:baz
foo.bar.baz

task and file task may take task arguments with which users can supply additional information used in task execution. Task arguments are defined as following:

(task ("hello" first-name last-name) ()
  (echo #?"Hello ${first-name} ${last-name}!"))

Here hello task takes two task arguments, first-name and last-name, and uses them in the task action to echo a line.

Task arguments may have their default value as following:

(task ("hello" (first-name "john") (last-name "doe") ()
  (echo #?"Hello ${first-name} ${last-name}!"))

To supply task arguments to a task, the task name followed by bracket enclosed string is passed to lake function:

> (lake "hello[john,doe]")
Hello john doe!

or lake command in the command line:

$ lake hello[john,doe]
Hello john doe!

If no task argument is supplied, environment variable whose name is the upcase of the name of the task argument is searched and its value is used if it is found. If no such an environment variable, the default value of the task argument is used. If no default value is defined, the task argument has nil.

Note that task arguments following the task name does not include spaces because the shell splits the command at the existence of the spaces.

$ lake hello[john, doe]
No task "hello[john," found.

If spaces are needed, the task name and following task arguments should be quoted.

$ lake "hello[billy bob, smith]"
Hello billy bob smith!

For convenience, if the string supplied to a task argument via a bracket enclosed string or an environment variable is "t", "nil" or their uppercase, it is read to t or nil and the task argument has the read value. Otherwise, the task argument has the string as it is without being read.

Lakefile modularity is quite easy without any special facilities, just load a Lakefile from another is enough. Tasks with same name are replaced with newer loaded as ones in a Lakefile. Namespaces with same name are merged into.

Lakefile

(load "Lakefile.sub")

(namespace "name"
  (task "foo"
    (echo "name.foo")))

Lakefile.sub

(namespace "name"
  (task "bar"
    (echo "name.bar")))

So you can execute the two tasks respectively as following.

$ ls
Lakefile Lakefile.sub
$ lake name:foo
name.foo
$ lake name:bar
name.bar

LAKE &key target pathname jobs verbose

Loads a Lakefile specified with pathname to execute a task of name target defined in the Lakefile. jobs as an integer gives how many tasks execute simultaneously. The default number is one, which means serial execution. Not nil verbose provides verbose mode. If target is not given, "default" is used for the default task name. If pathname is not given, a file of name Lakefile in the current directory is searched for. You should be aware that where the Common Lisp process' current directory is.

(lake :target "hello")

ECHO string

Writes the given string into the standard output followed by a new line, provided for UNIX terminology convenience.

(task "say-hello" ()
  (echo "Hello world!"))

SH command &key echo

Spawns a subprocess that runs the specified command given as a string or list of strings. When echo is not nil, prints command to the standard output before running it. Actually it is a very thin wrapper of uiop:run-program provided for UNIX terminology convenience. Acompanied with cl-interpol's #? reader macro, you get more analogous expressions to shell scripts.

(defparameter cc "gcc")

(task "hello" ("hello.c")
  (sh #?"${cc} -o hello hello.c"))

SSH command &key echo

Spawns a subprocess that runs the specified command, given as a string or list of strings, on a remote host using ssh(1). *ssh-host*, *ssh-user* and *ssh-identity* should be bound properly before use this. When echo is not nil, prints ssh command published to the standard output before running it.

(setf *ssh-host* "remotehost")
(setf *ssh-user* "user")
(task "hello-via-ssh" ()
  (ssh "echo Hello World!"))

Note that the following binding does not work as intended because the dynamic binding only keep when task macro is evaluated, have already exited when ssh function is to be actually evaluated.

;; Does not work as intended.
(let ((*ssh-host* "localhost")
      (*ssh-user* "`whoami`"))
  (task "hello-via-ssh" ()
    (ssh "echo Hello World!")))

Instead, the next works as intended. Anyway, the former style with setf would be enough in Lakefile.

;; Works as intended.
(task "hello-via-ssh" ()
  (let ((*ssh-host* "localhost")
        (*ssh-user* "`whoami`"))
    (ssh "echo Hello World!")))

These special variables are used to establish a secure connection using ssh function. The default value of *ssh-host* is unbound so it should be always bound properly when using secure connections. The default value of *ssh-user* is nil, for giving optional user name. The default value of *ssh-identity* is nil, for giving optional identity file to prove his/her identity to the remote machine.

SCP from-place pathspec1 to-place pathspec2 &key echo

Copies files between hosts on a network using scp(1). from-place, which must be :local or :remote, specifies if pathspec1 is a file path on local host or remote host respectively. pathspec1 is a file path to be copied from, given as a string or a pathname. to-place and pathspec2 are same as from-place and pathspec1 except that they are about files to be copied to.

As ssh function above, *ssh-host*, *ssh-user* and *ssh-identity* should be bound properly before use this. When echo is not nil, prints scp command published to the standard output before running it.

(setf *ssh-host* "remotehost")
(setf *ssh-user* "user")
(task "scp" ()
  "Copy ~/foo on local host to ~/foo on remote host."
  (scp :local "~/foo" :remote "~/foo"))

EXECUTE target

Executes a task specified with target as a string within another. The name of the target task is resolved as well as task macro's dependency list in both relative and absolute manner.

(task "hello" ("hello.c")
  (sh "gcc -o hello hello.c")
  (execute "ls"))

(task "ls" ()
  (sh "ls -l"))

DISPLAY-TASKS &key pathname verbose

Displays the tasks with descriptions in a Lakefile specified with pathname. Not nil verbose provides verbose mode. If pathname is not given, a file of name Lakefile in the current direcotry is searched for. You should be aware that where the Common Lisp process' current directory is.

(display-tasks)

Lake provides its command line interface as a roswell script or a binary, if built with the Homebrew.

SYNOPSIS

    lake [ -f lakefile ] [ options ] ... [ targets ] ...

OPTIONS

    -f, --file FILE
        Use FILE as a Lakefile.
    -h, --help
        Print usage.
    -j INTEGER
        Execute multiple tasks simultaneously.
    -T, --list
        Display the tasks with descriptions, then exit.
    -v, --verbose
        Verbose mode.

EXAMPLE

    $ lake hello:foo hello:bar

Lake also provides lake-tools command as a roswell script which is a complementary program to provide some useful goodies.

Here shows lake-tools command's detail. lake-tools init command would be replaced by roswell's ros init facility (See issue #12).

SYNOPSIS

    lake-tools COMMAND

COMMANDS

    dump    Prepare LAKE command to make it run much faster.
    init    Create an empty Lakefile with boilerplates in current directory.

EXAMPLE

    $ lake-tools init
    $ ls
    Lakefile

Originally lake was called clake, and @Rudolph-Miller gave its name and concept on his GitHub repository. Then, @takagi forked it to design, implement, test, document and CI independently. Afterwards it is renamed to lake.

• Rudolph Miller (chopsticks.tk.ppfm@gmail.com)
• Masayuki Takagi (kamonama@gmial.com)

Copyright (c) 2015 Rudolph Miller (chopsticks.tk.ppfm@gmail.com)

Licensed under the MIT License.