From 303a250fd057ce628ca179b87419b47fd93c6a27 Mon Sep 17 00:00:00 2001
From: David Anthoff <anthoff@berkeley.edu>
Date: Sun, 9 Jun 2019 20:44:13 -0700
Subject: [PATCH] Add lift macro

---
 src/DataValues.jl    |  3 ++-
 src/scalar/helper.jl | 14 ++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 src/scalar/helper.jl

diff --git a/src/DataValues.jl b/src/DataValues.jl
index 99a0198..5a99296 100644
--- a/src/DataValues.jl
+++ b/src/DataValues.jl
@@ -1,4 +1,3 @@
-__precompile__()
 module DataValues
 
 using Dates
@@ -9,6 +8,8 @@ export DataValueArray, DataValueVector, DataValueMatrix
 
 export isna, hasvalue, dropna, dropna!, padna!, padna
 
+include("scalar/helper.jl")
+
 include("scalar/core.jl")
 # TODO 0.7 migration, enable again
 # include("scalar/broadcast.jl")
diff --git a/src/scalar/helper.jl b/src/scalar/helper.jl
new file mode 100644
index 0000000..90a3558
--- /dev/null
+++ b/src/scalar/helper.jl
@@ -0,0 +1,14 @@
+macro lift(f_sign, ret_type)
+
+    func_name = f_sign.args[1].args[1]
+    arg_type_name = f_sign.args[1].args[2].args[2]
+    type_constraint = f_sign.args[2]
+
+    quote
+        function $(esc(func_name))(x::DataValue{$(esc(arg_type_name))}) where {$(esc(type_constraint))}
+            return isna(x) ? DataValue{$(esc(ret_type))}() : DataValue{$(esc(ret_type))}($(esc(func_name))(unsafe_get(x)))
+        end
+
+        $(esc(func_name))(::DataValue{Union{}}) = NA
+    end
+end