commit 3e1b3e3f374c784f673c75018a31af1beff2d9ac
Author: Ray Miller <ray@metail.co.uk>
Date:   Sun Jul 14 17:11:24 2024 +0100

    Initial check-in.

diff --git a/ordo/task.scm b/ordo/task.scm
new file mode 100644
index 0000000..2d10793
--- /dev/null
+++ b/ordo/task.scm
@@ -0,0 +1,10 @@
+(define-module (ordo task)
+  #:use-module (srfi srfi-9)
+  #:export (make-task task? task-name task-prerequisite-data set-task-prerequisite-data! task-action set-task-action!))
+
+(define-record-type <task>
+  (make-task name prerequisite-data action)
+  task?
+  (name task-name)
+  (prerequisite-data task-prerequisite-data set-task-prerequisite-data!)
+  (action task-action set-task-action!))
diff --git a/ordo/task/command.scm b/ordo/task/command.scm
new file mode 100644
index 0000000..181d3cc
--- /dev/null
+++ b/ordo/task/command.scm
@@ -0,0 +1,17 @@
+(define-module (ordo task command)
+  #:use-module (ice-9 format)
+  #:use-module (srfi srfi-11)
+  #:use-module (ordo task)
+  #:use-module (ordo util run)
+  #:export (task-command))
+
+
+(define* (task-command name cmd #:optional (args '())
+                       #:key (fail-ok? #f) (stdin #f) (cwd #f) (env #f))
+  (make-task name
+             #f
+             (lambda ()
+               (let-values (((exit-code output) (run cmd args #:stdin stdin #:cwd cwd #:env env #:combine-output #t)))
+                 (if (or fail-ok? (zero? exit-code))
+                     (values exit-code output)
+                     (error (format #f "Error running ~a (exit ~d): ~a" cmd exit-code output)))))))
diff --git a/ordo/util/run.scm b/ordo/util/run.scm
new file mode 100644
index 0000000..c394bc7
--- /dev/null
+++ b/ordo/util/run.scm
@@ -0,0 +1,30 @@
+(define-module (ordo util run)
+  #:use-module (ice-9 textual-ports)
+  #:export (run with-cwd))
+
+(define-syntax with-cwd
+  (syntax-rules ()
+    ((_ new-dir body ...)
+     (let ((original-dir (getcwd)))
+       (dynamic-wind
+         (lambda () (chdir new-dir))
+         (lambda () body ...)
+         (lambda () (chdir original-dir)))))))
+
+(define* (run cmd #:optional (args '()) #:key (combine-output #f) (env #f) (stdin #f) (cwd #f))
+  (if cwd
+      (with-cwd cwd (run cmd args #:combine-output combine-output #:env env #:stdin stdin))
+      (let* ((input-pipe (pipe))
+             (output-pipe (pipe))
+             (pid (spawn cmd (cons cmd args)
+                         #:input (car input-pipe)
+                         #:output (cdr output-pipe)
+                         #:error (if combine-output (cdr output-pipe) (current-error-port))
+                         #:environment (or env (environ)))))
+        (close-port (cdr output-pipe))
+        (close-port (car input-pipe))
+        (when stdin (put-string (cdr input-pipe) stdin))
+        (close-port (cdr input-pipe))
+        (let ((output (get-string-all (car output-pipe))))
+          (close-port (car output-pipe))
+          (values (cdr (waitpid pid)) output)))))