nix eval: Add option to write a directory

This is useful for generating the nix manpages, but it may have other
applications (like generating configuration files without a Nix store).

1 files changed, 8 insertions, 0 deletions

diff --git a/tests/pure-eval.sh b/tests/pure-eval.sh
index 43a765997..561ca53fb 100644
--- a/tests/pure-eval.sh
+++ b/tests/pure-eval.sh
@@ -16,3 +16,11 @@ nix eval --expr 'assert 1 + 2 == 3; true'
 [[ $(nix eval --impure --expr "(import (builtins.fetchurl { url = file://$(pwd)/pure-eval.nix; })).x") == 123 ]]
 (! nix eval --expr "(import (builtins.fetchurl { url = file://$(pwd)/pure-eval.nix; })).x")
 nix eval --expr "(import (builtins.fetchurl { url = file://$(pwd)/pure-eval.nix; sha256 = \"$(nix hash-file pure-eval.nix --type sha256)\"; })).x"
+
+rm -rf $TEST_ROOT/eval-out
+nix eval --store dummy:// --write-to $TEST_ROOT/eval-out --expr '{ x = "foo" + "bar"; y = { z = "bla"; }; }'
+[[ $(cat $TEST_ROOT/eval-out/x) = foobar ]]
+[[ $(cat $TEST_ROOT/eval-out/y/z) = bla ]]
+
+rm -rf $TEST_ROOT/eval-out
+(! nix eval --store dummy:// --write-to $TEST_ROOT/eval-out --expr '{ "." = "bla"; }')