94 lines
3 KiB
Nix
94 lines
3 KiB
Nix
|
{ pkgs, depot, lib, ... }:
|
||
|
|
let
|
||
|
|
|
||
|
|
# import the dhall file as nix expression via dhall-nix.
|
||
|
|
# Converts the normalized dhall expression to a nix file,
|
||
|
|
# puts it in the store and imports it.
|
||
|
|
# Types are erased, functions are converted to nix functions,
|
||
|
|
# unions values are nix functions that take a record of match
|
||
|
|
# functions for their alternatives.
|
||
|
|
# TODO: document better
|
||
|
|
importDhall =
|
||
|
|
{
|
||
|
|
# Root path of the dhall file tree to import (will be filtered by files)
|
||
|
|
root
|
||
|
|
, # A list of files which should be taken from `root` (relative paths).
|
||
|
|
# This is for minimizing the amount of things that have to be copied to the store.
|
||
|
|
# TODO: can you have directory prefixes?
|
||
|
|
files
|
||
|
|
, # The path of the dhall file which should be evaluated, relative to `root`, has to be in `files`
|
||
|
|
main
|
||
|
|
, # List of dependencies (TODO: what is a dependency?)
|
||
|
|
deps
|
||
|
|
, # dhall type of `main`, or `null` if anything should be possible.
|
||
|
|
type ? null
|
||
|
|
}:
|
||
|
|
let
|
||
|
|
absRoot = path: toString root + "/" + path;
|
||
|
|
src =
|
||
|
|
depot.users.Profpatsch.exactSource
|
||
|
|
root
|
||
|
|
# exactSource wants nix paths, but I think relative paths
|
||
|
|
# as strings are more intuitive.
|
||
|
|
([ (absRoot main) ] ++ (map absRoot files));
|
||
|
|
|
||
|
|
cache = ".cache";
|
||
|
|
cacheDhall = "${cache}/dhall";
|
||
|
|
|
||
|
|
hadTypeAnnot = type != null;
|
||
|
|
typeAnnot = lib.optionalString hadTypeAnnot ": ${type}";
|
||
|
|
|
||
|
|
convert = pkgs.runCommandLocal "dhall-to-nix" { inherit deps; } ''
|
||
|
|
mkdir -p ${cacheDhall}
|
||
|
|
for dep in $deps; do
|
||
|
|
${pkgs.xorg.lndir}/bin/lndir -silent $dep/${cacheDhall} ${cacheDhall}
|
||
|
|
done
|
||
|
|
|
||
|
|
export XDG_CACHE_HOME=$(pwd)/${cache}
|
||
|
|
# go into the source directory, so that the type can import files.
|
||
|
|
# TODO: This is a bit of a hack hrm.
|
||
|
|
cd "${src}"
|
||
|
|
printf 'Generating dhall nix code. Run
|
||
|
|
%s --file %s
|
||
|
|
to reproduce
|
||
|
|
' \
|
||
|
|
${pkgs.dhall}/bin/dhall \
|
||
|
|
${absRoot main}
|
||
|
|
${if hadTypeAnnot then ''
|
||
|
|
printf '%s' ${lib.escapeShellArg "${src}/${main} ${typeAnnot}"} \
|
||
|
|
| ${pkgs.dhall-nix}/bin/dhall-to-nix \
|
||
|
|
> $out
|
||
|
|
''
|
||
|
|
else ''
|
||
|
|
printf 'No type annotation given, the dhall expression type was:\n'
|
||
|
|
${pkgs.dhall}/bin/dhall type --file "${src}/${main}"
|
||
|
|
printf '%s' ${lib.escapeShellArg "${src}/${main}"} \
|
||
|
|
| ${pkgs.dhall-nix}/bin/dhall-to-nix \
|
||
|
|
> $out
|
||
|
|
''}
|
||
|
|
|
||
|
|
'';
|
||
|
|
in
|
||
|
|
import convert;
|
||
|
|
|
||
|
|
|
||
|
|
# read dhall file in as JSON, then import as nix expression.
|
||
|
|
# The dhall file must not try to import from non-local URLs!
|
||
|
|
readDhallFileAsJson = dhallType: file:
|
||
|
|
let
|
||
|
|
convert = pkgs.runCommandLocal "dhall-to-json" { } ''
|
||
|
|
printf '%s' ${lib.escapeShellArg "${file} : ${dhallType}"} \
|
||
|
|
| ${pkgs.dhall-json}/bin/dhall-to-json \
|
||
|
|
> $out
|
||
|
|
'';
|
||
|
|
in
|
||
|
|
builtins.fromJSON (builtins.readFile convert);
|
||
|
|
|
||
|
|
in
|
||
|
|
{
|
||
|
|
inherit
|
||
|
|
importDhall
|
||
|
|
readDhallFileAsJson
|
||
|
|
;
|
||
|
|
}
|