1 files changed, 71 insertions, 0 deletions
diff --git a/pkgs/profpatsch/execline/run-execline.nix b/pkgs/profpatsch/execline/run-execline.nix
new file mode 100644
index 00000000..2efe43d6
--- /dev/null
+++ b/pkgs/profpatsch/execline/run-execline.nix
@@ -0,0 +1,71 @@
+{ stdenv, bin, lib }:
+name:
+{
+# a string to pass as stdin to the execline script
+stdin ? ""
+# a program wrapping the acutal execline invocation;
+# should be in Bernstein-chaining style
+, builderWrapper ? bin.exec
+# additional arguments to pass to the derivation
+, derivationArgs ? {}
+}:
+# the execline script as a nested list of string,
+# representing the blocks;
+# see docs of `escapeExecline`.
+ execline:
+
+# those arguments can’t be overwritten
+assert !derivationArgs ? system;
+assert !derivationArgs ? name;
+assert !derivationArgs ? builder;
+assert !derivationArgs ? args;
+
+derivation (derivationArgs // {
+  # TODO: what about cross?
+  inherit (stdenv) system;
+  inherit name;
+
+  # okay, `builtins.toFile` does not accept strings
+  # that reference drv outputs. This means we need
+  # to pass the script and stdin as envvar;
+  # this might clash with another passed envar,
+  # so we give it a long & unique name
+  _runExeclineScript =
+    let
+      escape = (import ./escape.nix { inherit lib; });
+    in escape.escapeExecline execline;
+  _runExeclineStdin = stdin;
+  passAsFile = [
+    "_runExeclineScript"
+    "_runExeclineStdin"
+  ] ++ derivationArgs.passAsFile or [];
+
+  # the default, exec acts as identity executable
+  builder = builderWrapper;
+
+  args = [
+    bin.importas             # import script file as $script
+    "-ui"                    # drop the envvar afterwards
+    "script"                 # substitution name
+    "_runExeclineScriptPath" # passed script file
+
+    # TODO: can we scrap stdin via builderWrapper?
+    bin.importas             # do the same for $stdin
+    "-ui"
+    "stdin"
+    "_runExeclineStdinPath"
+
+    bin.redirfd              # now we
+    "-r"                     # read the file
+    "0"                      # into the stdin of execlineb
+    "$stdin"                 # that was given via stdin
+
+    bin.execlineb            # the actual invocation
+    # TODO: depending on the use-case, -S0 might not be enough
+    # in all use-cases, then a wrapper for execlineb arguments
+    # should be added (-P, -S, -s).
+    "-S0"                    # set $@ inside the execline script
+    "-W"                     # die on syntax error
+    "$script"                # substituted by importas
+  ];
+})