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| author | Eelco Dolstra <eelco.dolstra@logicblox.com> | 2013-10-28 04:46:36 +0100 |
|---|---|---|
| committer | Eelco Dolstra <eelco.dolstra@logicblox.com> | 2013-10-28 22:45:55 +0100 |
| commit | 40913958a2c61e49348d2038ae6f2a1d32c126fe (patch) | |
| tree | 02929d83462f084b245bcc7ebb948fbafc9b4c50 /lib/lists.nix | |
| parent | cfab329437a24811104bc8daa2b83b80614f753c (diff) | |
Keep position information for option declarations and definitions
Also, when an option definition fails to type-check, print the file
name of the module in which the offending definition occurs, e.g.
error: user-thrown exception: The option value `boot.loader.grub.version' in `/etc/nixos/configuration.nix' is not a integer.
Diffstat (limited to 'lib/lists.nix')
| -rw-r--r-- | lib/lists.nix | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/lib/lists.nix b/lib/lists.nix index eb7e6baf5ed8..d0b09539bf69 100644 --- a/lib/lists.nix +++ b/lib/lists.nix @@ -118,6 +118,11 @@ in rec { all = pred: fold (x: y: if pred x then y else false) true; + # Count how many times function `pred' returns true for the elements + # of `list'. + count = pred: fold (x: c: if pred x then inc c else c) 0; + + # Return a singleton list or an empty list, depending on a boolean # value. Useful when building lists with optional elements # (e.g. `++ optional (system == "i686-linux") flashplayer'). |