nixpkgs/pkgs/development/interpreters/dhall/build-dhall-package.nix
2021-11-07 20:18:45 +08:00

103 lines
3.0 KiB
Nix

{ dhall, dhall-docs, haskell, lib, lndir, runCommand, writeText }:
{ name
# Expressions to add to the cache before interpreting the code
, dependencies ? []
# A Dhall expression
#
# Carefully note that the following expression must be devoid of uncached HTTP
# imports. This is because the expression will be evaluated using an
# interpreter with HTTP support disabled, so all HTTP imports have to be
# protected by an integrity check that can be satisfied via cached
# dependencies.
#
# You can add a dependency to the cache using the preceding `dependencies`
# option
, code
# `buildDhallPackage` can include both a "source distribution" in
# `source.dhall` and a "binary distribution" in `binary.dhall`:
#
# * `source.dhall` is a dependency-free αβ-normalized Dhall expression
#
# * `binary.dhall` is an expression of the form: `missing sha256:${HASH}`
#
# This expression requires you to install the cache product located at
# `.cache/dhall/1220${HASH}` to successfully resolve
#
# By default, `buildDhallPackage` only includes "binary.dhall" to conserve
# space within the Nix store, but if you set the following `source` option to
# `true` then the package will also include `source.dhall`.
, source ? false
# Directory to generate documentation for (i.e. as the `--input` option to the
# `dhall-docs` command.)
#
# If `null`, then no documentation is generated.
, documentationRoot ? null
# Base URL prepended to paths copied to the clipboard
#
# This is used in conjunction with `documentationRoot`, and is unused if
# `documentationRoot` is `null`.
, baseImportUrl ? null
}:
let
# HTTP support is disabled in order to force that HTTP dependencies are built
# using Nix instead of using Dhall's support for HTTP imports.
dhallNoHTTP = haskell.lib.compose.appendConfigureFlag "-f-with-http" dhall;
file = writeText "${name}.dhall" code;
cache = ".cache";
data = ".local/share";
cacheDhall = "${cache}/dhall";
dataDhall = "${data}/dhall";
sourceFile = "source.dhall";
in
runCommand name { inherit dependencies; } ''
set -eu
mkdir -p ${cacheDhall}
for dependency in $dependencies; do
${lndir}/bin/lndir -silent $dependency/${cacheDhall} ${cacheDhall}
done
export XDG_CACHE_HOME=$PWD/${cache}
mkdir -p $out/${cacheDhall}
${dhallNoHTTP}/bin/dhall --alpha --file '${file}' > $out/${sourceFile}
SHA_HASH=$(${dhallNoHTTP}/bin/dhall hash <<< $out/${sourceFile})
HASH_FILE="''${SHA_HASH/sha256:/1220}"
${dhallNoHTTP}/bin/dhall encode --file $out/${sourceFile} > $out/${cacheDhall}/$HASH_FILE
echo "missing $SHA_HASH" > $out/binary.dhall
${lib.optionalString (!source) "rm $out/${sourceFile}"}
${lib.optionalString (documentationRoot != null) ''
mkdir -p $out/${dataDhall}
XDG_DATA_HOME=$out/${data} ${dhall-docs}/bin/dhall-docs --output-link $out/docs ${lib.cli.toGNUCommandLineShell { } {
base-import-url = baseImportUrl;
input = documentationRoot;
package-name = name;
}}
''}
''