unikernel/duniverse/dune_/example/with-configure-step.t/.gitignore

@@ -0,0 +1,2 @@
+config
+config.full

unikernel/duniverse/dune_/example/with-configure-step.t/README.md

@@ -0,0 +1,37 @@
+This project shows how to add a configure step to a project using Dune.
+
+In order to keep things composable, it offers several way to configure
+the project:
+
+1.  with the classic `./configure <args...>`. When doing this, the
+    configuration script are run immediately, and the resulting configuration
+    is frozen for the rest of the build.
+
+2.  by copying `config.defaults` to `config` and editing it. The configuration
+    scripts will be run as part of the build using what is written in `config`.
+    When `config` is edited, the configuration scripts will be automatically
+    rerun.
+
+3.  by doing nothing. The configuration scripts will be run as part of the
+    build using the default values provided in `config.defaults`.
+
+Technically this is how it works:
+
+`configure` is a simple OCaml script that:
+
+- parses the command line
+- generates a `config` file using what was given on the command line
+- calls `ocaml real_configure.ml`
+- `real_configure.ml` does some stuff and generates `config.full`
+
+`config.full` is what is used by the rest of the build.
+
+Now in order to support (2) and (3), we setup the following rules in the
+toplevel `dune` file:
+
+- a rule to produce `config` by copying `config.default`
+- a rule to produce `config.full` by running `real_configure.ml`
+
+This all works as described because if Dune knows how to build a file and this
+file is already present in the source tree, it will always prefer the file
+that's already there.

unikernel/duniverse/dune_/example/with-configure-step.t/config.defaults

@@ -0,0 +1,7 @@
+(* -*- tuareg -*- *)
+
+(* Default configuration, copy this file to "config" and edit it to change the build
+   configuration. Alternatively call ./configure *)
+
+(* Enable support for blah *)
+let enable_blah = Auto

unikernel/duniverse/dune_/example/with-configure-step.t/config_common.ml

@@ -0,0 +1,11 @@
+(* Various types used by configure and real_configure.ml *)
+
+type switch =
+  | Yes
+  | No
+  | Auto
+
+let string_of_switch = function
+  | Yes  -> "Yes"
+  | No   -> "No"
+  | Auto -> "Auto"

unikernel/duniverse/dune_/example/with-configure-step.t/configure

@@ -0,0 +1,27 @@
+#!/usr/bin/env ocaml
+(* -*- tuareg -*- *)
+
+#warnings "-40";;
+
+#use "config_common.ml"
+
+let () =
+  let enable_blah = ref Auto in
+  Arg.parse
+    (Arg.align
+       [ "--enable-blah", Unit (fun () -> enable_blah := Yes),
+         " Enable support for blah"
+       ; "--disable-blah", Unit (fun () -> enable_blah := No),
+         " Enable support for blah"
+       ])
+    (fun s -> raise (Arg.Bad (Printf.sprintf "don't know what to do with %S" s)))
+    "Usage: ./configure [OPTIONS]";
+  let oc = open_out_bin "config" in
+  Printf.fprintf oc {|
+let enable_blah = %s
+|}
+    (string_of_switch !enable_blah);
+  close_out oc
+;;
+
+#use "real_configure.ml"

unikernel/duniverse/dune_/example/with-configure-step.t/dune

@@ -0,0 +1,9 @@
+(rule
+ (mode fallback)
+ (targets config)
+ (action  (copy config.defaults %{targets})))
+
+(rule
+ (targets config.full)
+ (deps    config_common.ml config)
+ (action  (run ocaml %{dep:real_configure.ml})))

unikernel/duniverse/dune_/example/with-configure-step.t/dune-project

@@ -0,0 +1,2 @@
+(lang dune 1.1)
+(name myproject)

unikernel/duniverse/dune_/example/with-configure-step.t/myproject.opam

@@ -0,0 +1,11 @@
+opam-version: "2.0"
+version: "1.0"
+maintainer: "bob@sponge.com"
+authors: ["SpongeBob"]
+homepage: "https://github.com/SpongeBob/myproject"
+bug-reports: "https://github.com/SpongeCob/myproject/issues"
+dev-repo: "git+https://github.com/SpongeBob/myproject.git"
+license: "Apache-2.0"
+build: [
+  ["dune" "build" "-p" name "-j" jobs]
+]

unikernel/duniverse/dune_/example/with-configure-step.t/real_configure.ml

@@ -0,0 +1,24 @@
+#use "config_common.ml"
+#use "config"
+
+let with_blah =
+  match enable_blah with
+  | Yes  -> true
+  | No   -> false
+  | Auto -> true (* replace by some detection code *)
+
+let blah_path =
+  if with_blah then
+    (* replace by some relevant stuff *)
+    "/path/to/blah"
+  else
+    "<no support for blah>"
+
+let () =
+  let oc = open_out_bin "config.full" in
+  Printf.fprintf oc {|
+let with_blah = %B
+let blah_path = %S
+|}
+    with_blah blah_path
+

unikernel/duniverse/dune_/example/with-configure-step.t/run.t

@@ -0,0 +1,26 @@
+This example creates a configuration file using a fallback rule.
+See README.org for details
+
+By default, config is set:
+
+  $ dune exec ./src/plop.exe
+  Built with support for blah: true
+  Path to blah is:             "/path/to/blah"
+
+Print generated config:
+
+  $ cat _build/default/config.full
+  
+  let with_blah = true
+  let blah_path = "/path/to/blah"
+
+Now, we disable it, and re-run:
+
+  $ echo "let enable_blah = No" > config
+  $ dune exec ./src/plop.exe
+  Built with support for blah: false
+  Path to blah is:             "<no support for blah>"
+  $ cat _build/default/config.full
+  
+  let with_blah = false
+  let blah_path = "<no support for blah>"

unikernel/duniverse/dune_/example/with-configure-step.t/src/dune

@@ -0,0 +1,10 @@
+(executables
+ (names plop))
+
+(install
+ (section bin)
+ (files (plop.exe as plop)))
+
+(rule
+ (targets config.ml)
+ (action  (copy ../config.full %{targets})))

unikernel/duniverse/dune_/example/with-configure-step.t/src/plop.ml

@@ -0,0 +1,5 @@
+let () =
+  Printf.printf "Built with support for blah: %B\n\
+                 Path to blah is:             %S\n"
+    Config.with_blah
+    Config.blah_path