From 22d3587f3b850e8fc34add4d8e62911c6598ad78 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <e.dolstra@tudelft.nl>
Date: Tue, 12 Jul 2005 16:06:25 +0000
Subject: [PATCH] * In nix-instantiate, at top-level, call functions that have
arguments with default values automatically. I.e., e -> e {}.
This feature makes convenience expressions such as
pkgs/system/i686-linux.nix in Nixpkgs obsolete, since we can just do
$ nix-instantiate ./pkgs/system/all-packages.nix
since all-packages.nix takes a single argument (system) that has a
default value (__thisSystem).
---
src/nix-instantiate/main.cc | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/src/nix-instantiate/main.cc b/src/nix-instantiate/main.cc
index 3e9fad4ae..3161d17f4 100644
--- a/src/nix-instantiate/main.cc
+++ b/src/nix-instantiate/main.cc
@@ -73,6 +73,23 @@ static void printDrvPaths(EvalState & state, Expr e)
return;
}
+ ATermList formals;
+ ATerm body, pos;
+ if (matchFunction(e, formals, body, pos)) {
+ for (ATermIterator i(formals); i; ++i) {
+ Expr name, def;
+ if (matchNoDefFormal(*i, name))
+ throw Error(format("expression evaluates to a function with no-default arguments (`%1%')")
+ % aterm2String(name));
+ else if (!matchDefFormal(*i, name, def))
+ abort(); /* can't happen */
+ }
+
+ printDrvPaths(state, evalExpr(state,
+ makeCall(e, makeAttrs(ATermMap()))));
+ return;
+ }
+
throw Error("expression does not evaluate to one or more derivations");
}
--
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