fixed date with missing

src/loadjdf.jl

@@ -9,9 +9,7 @@ version is used.
 load(indir; cols = Symbol[], verbose = false) = begin
     # starting from DataFrames.jl 0.21 the colnames are strings
     cols = string.(cols)
-    metadatas = open(joinpath(indir, "metadata.jls")) do io
-        deserialize(io)
-    end
+    metadatas = jdfmetadata(indir)
 
     # TODO simplify this this is duplicated in load_columns
     if length(cols) == 0
@@ -34,9 +32,7 @@ sload(jdf::JDFFile; args...) = sload(path(jdf); args...)
 # load the data from file with a schema
 function sload(indir; cols = Symbol[], verbose = false)
     cols = string.(cols)
-    metadatas = open(joinpath(indir, "metadata.jls")) do io
-        deserialize(io)
-    end
+    metadatas = jdfmetadata(indir)
 
     # TODO simplify this
     if length(cols) == 0

src/savejdf.jl

@@ -5,7 +5,7 @@ using Tables
 
 Some arbitrary element of type `T`
 """
-some_elm(::Type{T}) where {T} = begin
+function some_elm(::Type{T}) where {T}
     try
         return zero(T)
     catch
@@ -25,6 +25,8 @@ some_elm(::Type{T}) where {T} = begin
     end
 end
 
+some_elm(::Type{Date}) = Date(0)
+
 """
     JDF.save(outdir, table)
 

src/type-writer-loader/Missing.jl

@@ -4,7 +4,7 @@ some_elm(::Type{Missing}) = missing
 
 
 # the dispatch for Union{T, Missing}
-# 1. comporess the missing
+# 1. compress the missing
 # 2. and also load the missing
 compress_then_write(b::Vector{Union{T,Missing}}, io) where {T} = begin
     S = nonmissingtype(eltype(b))
@@ -24,7 +24,8 @@ compress_then_write(b::Vector{Union{T,Missing}}, io) where {T} = begin
 end
 
 # just write it out as missing
-compress_then_write(b::Vector{Missing}, io) =
+# notice how io is not needed since nothing need to be written
+compress_then_write(b::Vector{Missing}, _) =
     (len = 0, type = Missing, orig_len = length(b))
 
 column_loader!(buffer, ::Type{Union{Missing,T}}, io, metadata) where {T} = begin

test/test-date-w-missing.jl

@@ -0,0 +1,8 @@
+# Guard aginst github #62
+using JDF
+using Dates
+col = [Date(1999,1,1), missing]
+df = (d = col, a = [1, missing])
+JDF.save("plsdel-date-w-missing.jdf", df)
+DataFrame(JDF.load("plsdel-date-w-missing.jdf"))
+rm("plsdel-date-w-missing.jdf", recursive=true)