From 9ad8e3cc8eaec92169d334039fe0fd00807a72af Mon Sep 17 00:00:00 2001
From: Tony Lian <1040424979@qq.com>
Date: Sun, 10 Mar 2019 14:27:30 -0700
Subject: [PATCH 01/22] Add writing support

---
 src/C_interface.jl | 28 +++++++++++++++++++++++
 src/ReadStat.jl    | 55 +++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 82 insertions(+), 1 deletion(-)

diff --git a/src/C_interface.jl b/src/C_interface.jl
index aee677e..926ffd8 100644
--- a/src/C_interface.jl
+++ b/src/C_interface.jl
@@ -69,4 +69,32 @@ end
 
 function readstat_parse(filename::String, type::Val{:sas7bdat}, parser::Ptr{Nothing}, ds::ReadStatDataFrame)
     return ccall((:readstat_parse_sas7bdat, libreadstat), Int, (Ptr{Nothing}, Cstring, Any), parser, string(filename), ds)
+end
+
+function readstat_begin_row(writer)
+    return ccall((:readstat_begin_row), Int, (Ptr{Nothing},), writer)
+end
+
+function readstat_end_row(writer)
+    return ccall((:readstat_end_row), Int, (Ptr{Nothing},), writer)
+end
+
+function readstat_begin_writing(writer, filetype::Val{:dta}, io, row_count)
+    return ccall((:readstat_begin_writing_dta, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, io, Cint(row_count))
+end
+
+function readstat_begin_writing(writer, filetype::Val{:sav}, io, row_count)
+    return ccall((:readstat_begin_writing_sav, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, io, Cint(row_count))
+end
+
+function readstat_begin_writing(writer, filetype::Val{:por}, io, row_count)
+    return ccall((:readstat_begin_writing_por, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, io, Cint(row_count))
+end
+
+function readstat_begin_writing(writer, filetype::Val{:sas7bdat}, io, row_count)
+    return ccall((:readstat_begin_writing_sas7bdat, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, io, Cint(row_count))
+end
+
+function readstat_insert_double_value(writer, variable, item)
+    return ccall((:readstat_insert_double_value, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Any), writer, variable, item)
 end
\ No newline at end of file
diff --git a/src/ReadStat.jl b/src/ReadStat.jl
index a56931f..250997f 100644
--- a/src/ReadStat.jl
+++ b/src/ReadStat.jl
@@ -248,7 +248,7 @@ function Parser()
     ccall((:readstat_set_value_handler, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}), parser, val_fxn)
     ccall((:readstat_set_value_label_handler, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}), parser, label_fxn)
     return parser
-end  
+end
 
 function parse_data_file!(ds::ReadStatDataFrame, parser::Ptr{Nothing}, filename::AbstractString, filetype::Val)
     retval = readstat_parse(filename, filetype, parser, ds)
@@ -256,9 +256,62 @@ function parse_data_file!(ds::ReadStatDataFrame, parser::Ptr{Nothing}, filename:
     retval == 0 ||  error("Error parsing $filename: $retval")
 end
 
+
+function handle_write!()
+
+end
+
+function Writer(source; file_label="File Label")
+    writer = ccall((:readstat_writer_init, libreadstat), Ptr{Nothing}, ())
+    write_bytes = @cfunction(handle_write!, Cint, (Cint, Cint, Ptr{ReadStatDataFrame}))
+    ccall((:readstat_set_data_writer, libreadstat), Int, (Ptr{Nothing}, ), parser, write_bytes)
+    ccall((:readstat_writer_set_file_label, libreadstat, Cvoid, (Ptr{Nothing}, Cstring), writer, file_label)
+    return writer
+end
+
+function write_data_file(filename::AbstractString, filetype::Val, io::IO, source)
+    writer = Writer(source)
+    fields = fieldnames(eltype(source))
+    variables_array = []
+
+    for field in fields:
+        variable = ccall((:readstat_add_variable, libreadstat), Ptr{Nothing}, (Ptr{Nothing}, Cstring, Cint, Cint), writer, String(field), READSTAT_TYPE_DOUBLE, 0); # TODO: know width
+        readstat_variable_set_label(variable, String(field))
+        variables_array.push!(variable)
+    
+    variables = NamedTuple{(fields...,)}((variables...,)) # generate a NamedTuple for variables
+
+    
+    if Base.IteratorSize(source) == Base.HasLength(): # TODO: what about HasShape
+        row_count = length(q)
+    else: #fallback
+        row_count = 0
+        for _ in source
+            row_count += 1
+        end
+
+    readstat_begin_writing(writer, filetype, io, row_count)
+
+    for row in source
+        readstat_begin_row(writer)
+        for field in fields
+            readstat_insert_double_value(writer, variables[field], row[field]) # TODO: more than double
+        end
+        readstat_end_row(writer);
+    end
+
+    ccall((:readstat_end_writing, libreadstat), Int, (Ptr{Nothing}), writer)
+    ccall((:readstat_writer_free, libreadstat), Cvoid, (Ptr{Nothing}), writer)
+end
+
 read_dta(filename::AbstractString) = read_data_file(filename, Val(:dta))
 read_sav(filename::AbstractString) = read_data_file(filename, Val(:sav))
 read_por(filename::AbstractString) = read_data_file(filename, Val(:por))
 read_sas7bdat(filename::AbstractString) = read_data_file(filename, Val(:sas7bdat))
 
+write_dta(filename::AbstractString, io::IO, source) = write_data_file(filename, Val(:dta), io, source)
+write_sav(filename::AbstractString, io::IO, source) = write_data_file(filename, Val(:sav), io, source)
+write_por(filename::AbstractString, io::IO, source) = write_data_file(filename, Val(:por), io, source)
+write_sas7bdat(filename::AbstractString, io::IO, source) = write_data_file(filename, Val(:sas7bdat), io, source)
+
 end #module ReadStat

From 1bbaef1f2ab8d7608a461dfa53714087ff542736 Mon Sep 17 00:00:00 2001
From: Tony Lian <1040424979@qq.com>
Date: Tue, 19 Mar 2019 23:00:30 -0700
Subject: [PATCH 02/22] Add libreadstat into readstat_begin_row and
 readstat_end_row, pass pointer into readstat_begin_writing

---
 src/C_interface.jl | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/C_interface.jl b/src/C_interface.jl
index 926ffd8..c9bc705 100644
--- a/src/C_interface.jl
+++ b/src/C_interface.jl
@@ -72,27 +72,27 @@ function readstat_parse(filename::String, type::Val{:sas7bdat}, parser::Ptr{Noth
 end
 
 function readstat_begin_row(writer)
-    return ccall((:readstat_begin_row), Int, (Ptr{Nothing},), writer)
+    return ccall((:readstat_begin_row, libreadstat), Int, (Ptr{Nothing},), writer)
 end
 
 function readstat_end_row(writer)
-    return ccall((:readstat_end_row), Int, (Ptr{Nothing},), writer)
+    return ccall((:readstat_end_row, libreadstat), Int, (Ptr{Nothing},), writer)
 end
 
 function readstat_begin_writing(writer, filetype::Val{:dta}, io, row_count)
-    return ccall((:readstat_begin_writing_dta, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, io, Cint(row_count))
+    return ccall((:readstat_begin_writing_dta, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, pointer_from_objref(io), Cint(row_count))
 end
 
 function readstat_begin_writing(writer, filetype::Val{:sav}, io, row_count)
-    return ccall((:readstat_begin_writing_sav, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, io, Cint(row_count))
+    return ccall((:readstat_begin_writing_sav, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, pointer_from_objref(io), Cint(row_count))
 end
 
 function readstat_begin_writing(writer, filetype::Val{:por}, io, row_count)
-    return ccall((:readstat_begin_writing_por, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, io, Cint(row_count))
+    return ccall((:readstat_begin_writing_por, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, pointer_from_objref(io), Cint(row_count))
 end
 
 function readstat_begin_writing(writer, filetype::Val{:sas7bdat}, io, row_count)
-    return ccall((:readstat_begin_writing_sas7bdat, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, io, Cint(row_count))
+    return ccall((:readstat_begin_writing_sas7bdat, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, pointer_from_objref(io), Cint(row_count))
 end
 
 function readstat_insert_double_value(writer, variable, item)

From 150e1cde46e1a57b5cd0716d34e638f09b13d542 Mon Sep 17 00:00:00 2001
From: Tony Lian <1040424979@qq.com>
Date: Tue, 19 Mar 2019 23:00:51 -0700
Subject: [PATCH 03/22] Add handle_write and fix several syntax errors

---
 src/ReadStat.jl | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/src/ReadStat.jl b/src/ReadStat.jl
index 250997f..38aa5b7 100644
--- a/src/ReadStat.jl
+++ b/src/ReadStat.jl
@@ -256,16 +256,17 @@ function parse_data_file!(ds::ReadStatDataFrame, parser::Ptr{Nothing}, filename:
     retval == 0 ||  error("Error parsing $filename: $retval")
 end
 
-
-function handle_write!()
-
-end
+function handle_write!(data::Ptr, len::Int, ctx::Ptr)
+    io = unsafe_pointer_to_objref(ctx) # restore io
+    actual_data = unsafe_wrap(Array{Any}, data, len) # we may want to specify the type later
+    write(io, actual_data)
+ end
 
 function Writer(source; file_label="File Label")
     writer = ccall((:readstat_writer_init, libreadstat), Ptr{Nothing}, ())
     write_bytes = @cfunction(handle_write!, Cint, (Cint, Cint, Ptr{ReadStatDataFrame}))
-    ccall((:readstat_set_data_writer, libreadstat), Int, (Ptr{Nothing}, ), parser, write_bytes)
-    ccall((:readstat_writer_set_file_label, libreadstat, Cvoid, (Ptr{Nothing}, Cstring), writer, file_label)
+    ccall((:readstat_set_data_writer, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}), parser, write_bytes)
+    ccall((:readstat_writer_set_file_label, libreadstat), Cvoid, (Ptr{Nothing}, Cstring), writer, file_label)
     return writer
 end
 
@@ -274,21 +275,25 @@ function write_data_file(filename::AbstractString, filetype::Val, io::IO, source
     fields = fieldnames(eltype(source))
     variables_array = []
 
-    for field in fields:
-        variable = ccall((:readstat_add_variable, libreadstat), Ptr{Nothing}, (Ptr{Nothing}, Cstring, Cint, Cint), writer, String(field), READSTAT_TYPE_DOUBLE, 0); # TODO: know width
+    for field in fields
+        variable = ccall((:readstat_add_variable, libreadstat), 
+            Ptr{Nothing}, (Ptr{Nothing}, Cstring, Cint, Cint), 
+            writer, String(field), READSTAT_TYPE_DOUBLE, Cint(0)) # TODO: know width
         readstat_variable_set_label(variable, String(field))
         variables_array.push!(variable)
+    end
     
     variables = NamedTuple{(fields...,)}((variables...,)) # generate a NamedTuple for variables
 
     
-    if Base.IteratorSize(source) == Base.HasLength(): # TODO: what about HasShape
+    if Base.IteratorSize(source) == Base.HasLength() # TODO: what about HasShape
         row_count = length(q)
-    else: #fallback
+    else #fallback
         row_count = 0
         for _ in source
             row_count += 1
         end
+    end
 
     readstat_begin_writing(writer, filetype, io, row_count)
 
@@ -300,8 +305,8 @@ function write_data_file(filename::AbstractString, filetype::Val, io::IO, source
         readstat_end_row(writer);
     end
 
-    ccall((:readstat_end_writing, libreadstat), Int, (Ptr{Nothing}), writer)
-    ccall((:readstat_writer_free, libreadstat), Cvoid, (Ptr{Nothing}), writer)
+    ccall((:readstat_end_writing, libreadstat), Int, (Ptr{Nothing},), writer)
+    ccall((:readstat_writer_free, libreadstat), Cvoid, (Ptr{Nothing},), writer)
 end
 
 read_dta(filename::AbstractString) = read_data_file(filename, Val(:dta))

From fcfc6fe418cf3e0a9fc38214aee9d420191334c4 Mon Sep 17 00:00:00 2001
From: Tony Lian <1040424979@qq.com>
Date: Sat, 23 Mar 2019 20:49:43 -0700
Subject: [PATCH 04/22] Update writing

---
 src/ReadStat.jl | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/src/ReadStat.jl b/src/ReadStat.jl
index 38aa5b7..963e880 100644
--- a/src/ReadStat.jl
+++ b/src/ReadStat.jl
@@ -256,21 +256,29 @@ function parse_data_file!(ds::ReadStatDataFrame, parser::Ptr{Nothing}, filename:
     retval == 0 ||  error("Error parsing $filename: $retval")
 end
 
-function handle_write!(data::Ptr, len::Int, ctx::Ptr)
+function handle_write!(data::Ptr{UInt8}, len::Cint, ctx::Ptr)
     io = unsafe_pointer_to_objref(ctx) # restore io
-    actual_data = unsafe_wrap(Array{Any}, data, len) # we may want to specify the type later
+    actual_data = unsafe_wrap(Array{UInt8}, data, (len, )) # we may want to specify the type later
     write(io, actual_data)
+    return len
  end
 
 function Writer(source; file_label="File Label")
     writer = ccall((:readstat_writer_init, libreadstat), Ptr{Nothing}, ())
-    write_bytes = @cfunction(handle_write!, Cint, (Cint, Cint, Ptr{ReadStatDataFrame}))
-    ccall((:readstat_set_data_writer, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}), parser, write_bytes)
+    write_bytes = @cfunction(handle_write!, Cint, (Ptr{UInt8}, Cint, Ptr{Nothing}))
+    ccall((:readstat_set_data_writer, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}), writer, write_bytes)
     ccall((:readstat_writer_set_file_label, libreadstat), Cvoid, (Ptr{Nothing}, Cstring), writer, file_label)
     return writer
 end
 
-function write_data_file(filename::AbstractString, filetype::Val, io::IO, source)
+function write_data_file(filename::AbstractString, filetype::Val, source) 
+    io = open(filename, "w")
+    write_data_file(filetype::Val, io, source)
+    close(io)
+end
+
+
+function write_data_file(filetype::Val, io::IO, source)
     writer = Writer(source)
     fields = fieldnames(eltype(source))
     variables_array = []
@@ -279,15 +287,14 @@ function write_data_file(filename::AbstractString, filetype::Val, io::IO, source
         variable = ccall((:readstat_add_variable, libreadstat), 
             Ptr{Nothing}, (Ptr{Nothing}, Cstring, Cint, Cint), 
             writer, String(field), READSTAT_TYPE_DOUBLE, Cint(0)) # TODO: know width
-        readstat_variable_set_label(variable, String(field))
-        variables_array.push!(variable)
+        # readstat_variable_set_label(variable, String(field)) TODO: label for a variable
+        push!(variables_array, variable)
     end
     
-    variables = NamedTuple{(fields...,)}((variables...,)) # generate a NamedTuple for variables
+    variables = NamedTuple{(fields...,)}((variables_array...,)) # generate a NamedTuple for variables
 
-    
     if Base.IteratorSize(source) == Base.HasLength() # TODO: what about HasShape
-        row_count = length(q)
+        row_count = length(source)
     else #fallback
         row_count = 0
         for _ in source

From 9f5c76e65c26761cc6a352ad825552e1832787a8 Mon Sep 17 00:00:00 2001
From: Tony Lian <1040424979@qq.com>
Date: Sun, 24 Mar 2019 16:06:39 -0700
Subject: [PATCH 05/22] Change functions for writing and export write functions

---
 src/ReadStat.jl | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/ReadStat.jl b/src/ReadStat.jl
index 963e880..ff4d540 100644
--- a/src/ReadStat.jl
+++ b/src/ReadStat.jl
@@ -18,7 +18,7 @@ include(depsjl_path)
 using DataValues: DataValueVector
 using Dates
 
-export ReadStatDataFrame, read_dta, read_sav, read_por, read_sas7bdat
+export ReadStatDataFrame, read_dta, read_sav, read_por, read_sas7bdat, write_dta, write_sav, write_por, write_sas7bdat
 
 ##############################################################################
 ##
@@ -321,9 +321,9 @@ read_sav(filename::AbstractString) = read_data_file(filename, Val(:sav))
 read_por(filename::AbstractString) = read_data_file(filename, Val(:por))
 read_sas7bdat(filename::AbstractString) = read_data_file(filename, Val(:sas7bdat))
 
-write_dta(filename::AbstractString, io::IO, source) = write_data_file(filename, Val(:dta), io, source)
-write_sav(filename::AbstractString, io::IO, source) = write_data_file(filename, Val(:sav), io, source)
-write_por(filename::AbstractString, io::IO, source) = write_data_file(filename, Val(:por), io, source)
-write_sas7bdat(filename::AbstractString, io::IO, source) = write_data_file(filename, Val(:sas7bdat), io, source)
+write_dta(filename::AbstractString, source) = write_data_file(filename, Val(:dta), source)
+write_sav(filename::AbstractString, source) = write_data_file(filename, Val(:sav), source)
+write_por(filename::AbstractString, source) = write_data_file(filename, Val(:por), source)
+write_sas7bdat(filename::AbstractString, source) = write_data_file(filename, Val(:sas7bdat), source)
 
 end #module ReadStat

From dd9da3f08262ed2f314721d1c1f0239d03e602eb Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 09:30:40 +0200
Subject: [PATCH 06/22] remove merge artifact

---
 src/ReadStat.jl | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/src/ReadStat.jl b/src/ReadStat.jl
index 6f559a6..6337ee0 100644
--- a/src/ReadStat.jl
+++ b/src/ReadStat.jl
@@ -276,13 +276,10 @@ function Parser()
     ccall((:readstat_set_value_label_handler, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}), parser, label_fxn)
     return parser
 end
-<<<<<<< HEAD
-=======
 
 function error_message(retval::Integer)
     unsafe_string(ccall((:readstat_error_message, libreadstat), Ptr{Cchar}, (Cint,), retval))
 end
->>>>>>> master
 
 function error_message(retval::Integer)
     unsafe_string(ccall((:readstat_error_message, libreadstat), Ptr{Cchar}, (Cint,), retval))

From e952bdcfabdb77e5038acde1d331e6c9f36597f9 Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 09:42:25 +0200
Subject: [PATCH 07/22] add write_xport

---
 src/ReadStat.jl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/ReadStat.jl b/src/ReadStat.jl
index 6337ee0..158f5bd 100644
--- a/src/ReadStat.jl
+++ b/src/ReadStat.jl
@@ -361,5 +361,6 @@ write_dta(filename::AbstractString, source) = write_data_file(filename, Val(:dta
 write_sav(filename::AbstractString, source) = write_data_file(filename, Val(:sav), source)
 write_por(filename::AbstractString, source) = write_data_file(filename, Val(:por), source)
 write_sas7bdat(filename::AbstractString, source) = write_data_file(filename, Val(:sas7bdat), source)
+write_xport(filename::AbstractString, source) = write_data_file(filename, Val(:xport), source)
 
 end #module ReadStat

From adca45e7decadf010bf64c7f04ef965fe9604ef0 Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 10:52:55 +0200
Subject: [PATCH 08/22] ignore write_tests

---
 .gitignore | 1 +
 1 file changed, 1 insertion(+)

diff --git a/.gitignore b/.gitignore
index 369ae03..9df679a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@ deps/build.log
 *.jl.mem
 Manifest.toml
 .vscode
+test/write_tests/
\ No newline at end of file

From bc9fd1f4b4d4076d8d9718c7785884ecbcfd3631 Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 10:53:09 +0200
Subject: [PATCH 09/22] add Tables as dependency

---
 Project.toml | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/Project.toml b/Project.toml
index 761d41d..6ac772b 100644
--- a/Project.toml
+++ b/Project.toml
@@ -3,17 +3,18 @@ uuid = "d71aba96-b539-5138-91ee-935c3ee1374c"
 version = "1.1.2-DEV"
 
 [deps]
-Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
 DataValues = "e7dc6d0d-1eca-5fa6-8ad6-5aecde8b7ea5"
+Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
 ReadStat_jll = "a4dc8951-f1cc-5499-9034-9ec1c3e64557"
-
-[extras]
-Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"
 
 [compat]
-julia = "1.3"
 DataValues = "0.4.13"
 ReadStat_jll = "1.1.1"
+julia = "1.3"
+
+[extras]
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
 test = ["Test"]

From b952f76792d666e9d80642d5a041d5afdc427cf1 Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 10:53:19 +0200
Subject: [PATCH 10/22] add xport write function

---
 src/C_interface.jl | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/C_interface.jl b/src/C_interface.jl
index 084a1a2..4b53d5a 100644
--- a/src/C_interface.jl
+++ b/src/C_interface.jl
@@ -104,6 +104,10 @@ function readstat_begin_writing(writer, filetype::Val{:sas7bdat}, io, row_count)
     return ccall((:readstat_begin_writing_sas7bdat, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, pointer_from_objref(io), Cint(row_count))
 end
 
+function readstat_begin_writing(writer, filetype::Val{:xport}, io, row_count)
+    return ccall((:readstat_begin_writing_xport, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, pointer_from_objref(io), Cint(row_count))
+end
+
 function readstat_insert_double_value(writer, variable, item)
     return ccall((:readstat_insert_double_value, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Any), writer, variable, item)
 end
\ No newline at end of file

From 9913a386429507296876235b5c03bf2572fc8614 Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 10:55:00 +0200
Subject: [PATCH 11/22] make writing doubles work again

---
 src/ReadStat.jl  | 35 ++++++++++++-----------------
 test/runtests.jl | 57 ++++++++++++++++++++++++++++++++++--------------
 2 files changed, 55 insertions(+), 37 deletions(-)

diff --git a/src/ReadStat.jl b/src/ReadStat.jl
index 158f5bd..fa38531 100644
--- a/src/ReadStat.jl
+++ b/src/ReadStat.jl
@@ -11,8 +11,9 @@ using ReadStat_jll
 using DataValues: DataValueVector
 import DataValues
 using Dates
+import Tables
 
-export ReadStatDataFrame, read_dta, read_sav, read_por, read_sas7bdat, read_xport, write_dta, write_sav, write_por, write_sas7bdat
+export ReadStatDataFrame, read_dta, read_sav, read_por, read_sas7bdat, read_xport, write_dta, write_sav, write_por, write_sas7bdat, write_xport
 
 ##############################################################################
 ##
@@ -315,34 +316,24 @@ end
 
 function write_data_file(filetype::Val, io::IO, source)
     writer = Writer(source)
-    fields = fieldnames(eltype(source))
+
+    rows = Tables.rows(source)
+    schema = Tables.schema(rows)
     variables_array = []
 
-    for field in fields
-        variable = ccall((:readstat_add_variable, libreadstat), 
+    variables_array = map(Tables.columnnames(source)) do column_name
+        return ccall((:readstat_add_variable, libreadstat), 
             Ptr{Nothing}, (Ptr{Nothing}, Cstring, Cint, Cint), 
-            writer, String(field), READSTAT_TYPE_DOUBLE, Cint(0)) # TODO: know width
+            writer, String(column_name), READSTAT_TYPE_DOUBLE, Cint(0)) # TODO: know width
         # readstat_variable_set_label(variable, String(field)) TODO: label for a variable
-        push!(variables_array, variable)
     end
     
-    variables = NamedTuple{(fields...,)}((variables_array...,)) # generate a NamedTuple for variables
-
-    if Base.IteratorSize(source) == Base.HasLength() # TODO: what about HasShape
-        row_count = length(source)
-    else #fallback
-        row_count = 0
-        for _ in source
-            row_count += 1
-        end
-    end
+    readstat_begin_writing(writer, filetype, io, length(rows))
 
-    readstat_begin_writing(writer, filetype, io, row_count)
-
-    for row in source
+    for row in rows
         readstat_begin_row(writer)
-        for field in fields
-            readstat_insert_double_value(writer, variables[field], row[field]) # TODO: more than double
+        Tables.eachcolumn(schema, row) do val, i, name
+            insert_value!(writer, variables_array[i], val)
         end
         readstat_end_row(writer);
     end
@@ -351,6 +342,8 @@ function write_data_file(filetype::Val, io::IO, source)
     ccall((:readstat_writer_free, libreadstat), Cvoid, (Ptr{Nothing},), writer)
 end
 
+insert_value!(writer, variable, value::Float64) = readstat_insert_double_value(writer, variable, value)
+
 read_dta(filename::AbstractString) = read_data_file(filename, Val(:dta))
 read_sav(filename::AbstractString) = read_data_file(filename, Val(:sav))
 read_por(filename::AbstractString) = read_data_file(filename, Val(:por))
diff --git a/test/runtests.jl b/test/runtests.jl
index dbc10b0..d37f754 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -2,22 +2,47 @@ using ReadStat
 using DataValues
 using Test
 
-@testset "ReadStat: $ext files" for (reader, ext) in
-    ((read_dta, "dta"),
-     (read_sav, "sav"),
-     (read_sas7bdat, "sas7bdat"),
-     (read_xport, "xpt"))
+testdir = joinpath(@__DIR__, "write_tests")
+if isdir(testdir)
+    rm(testdir, recursive = true)
+end
+mkdir(testdir)
+
+@testset "ReadStat: $ext files" for (reader, writer, ext) in
+    ((read_dta, write_dta, "dta"),
+     (read_sav, write_sav, "sav"),
+     (read_sas7bdat, write_sas7bdat, "sas7bdat"),
+     (read_xport, write_xport, "xpt"))
+
+    @testset "Reading" begin
+        dtafile = joinpath(@__DIR__, "types.$ext")
+        rsdf = reader(dtafile)
+        data = rsdf.data
 
-    dtafile = joinpath(dirname(@__FILE__), "types.$ext")
-    rsdf = reader(dtafile)
-    data = rsdf.data
+        @test length(data) == 6
+        @test rsdf.headers == [:vfloat, :vdouble, :vlong, :vint, :vbyte, :vstring]
+        @test data[1] == DataValueArray{Float32}([3.14, 7., NA])
+        @test data[2] == DataValueArray{Float64}([3.14, 7., NA])
+        @test data[3] == DataValueArray{Int32}([2, 7, NA])
+        @test data[4] == DataValueArray{Int16}([2, 7, NA])
+        @test data[5] == DataValueArray{Int8}([2, 7., NA])
+        @test data[6] == DataValueArray{String}(["2", "7", ""])
+    end
 
-    @test length(data) == 6
-    @test rsdf.headers == [:vfloat, :vdouble, :vlong, :vint, :vbyte, :vstring]
-    @test data[1] == DataValueArray{Float32}([3.14, 7., NA])
-    @test data[2] == DataValueArray{Float64}([3.14, 7., NA])
-    @test data[3] == DataValueArray{Int32}([2, 7, NA])
-    @test data[4] == DataValueArray{Int16}([2, 7, NA])
-    @test data[5] == DataValueArray{Int8}([2, 7., NA])
-    @test data[6] == DataValueArray{String}(["2", "7", ""])
+    @testset "Writing" begin
+        data = (
+            vdouble = [3.14, 7.],
+            # vfloat = [3.14f0, 7.f0, missing],
+            # vlong = [2, 7, missing],
+            # vint = [Int16(2), Int16(7), missing],
+            # vbyte = [Int8(2), Int8(7), missing],
+            # vstring = ["2", "7", ""],
+        )
+        filepath = joinpath(testdir, "testwrite.$ext")
+        writer(filepath, data)
+        rsdf = reader(filepath)
+        data_read = rsdf.data
+        @test length(data_read) == length(data)
+        @test rsdf.headers == [:vdouble]
+    end
 end

From d40c96bceb71c54a145facb8a86b1b38164b289a Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 11:00:49 +0200
Subject: [PATCH 12/22] refactor double type

---
 src/C_interface.jl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/C_interface.jl b/src/C_interface.jl
index 4b53d5a..7896f8b 100644
--- a/src/C_interface.jl
+++ b/src/C_interface.jl
@@ -108,6 +108,6 @@ function readstat_begin_writing(writer, filetype::Val{:xport}, io, row_count)
     return ccall((:readstat_begin_writing_xport, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, pointer_from_objref(io), Cint(row_count))
 end
 
-function readstat_insert_double_value(writer, variable, item)
-    return ccall((:readstat_insert_double_value, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Any), writer, variable, item)
+function readstat_insert_double_value(writer, variable, value)
+    return ccall((:readstat_insert_double_value, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cdouble), writer, variable, value)
 end
\ No newline at end of file

From b77a19d095259539a80eccb1ef61dd38074c4b90 Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 11:05:08 +0200
Subject: [PATCH 13/22] add more insertion functions

---
 src/C_interface.jl | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/src/C_interface.jl b/src/C_interface.jl
index 7896f8b..f7fc357 100644
--- a/src/C_interface.jl
+++ b/src/C_interface.jl
@@ -110,4 +110,28 @@ end
 
 function readstat_insert_double_value(writer, variable, value)
     return ccall((:readstat_insert_double_value, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cdouble), writer, variable, value)
-end
\ No newline at end of file
+end
+
+function readstat_insert_float_value(writer, variable, value)
+    return ccall((:readstat_insert_float_value, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cfloat), writer, variable, value)
+end
+
+function readstat_insert_int32_value(writer, variable, value)
+    return ccall((:readstat_insert_int32_value, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cint), writer, variable, value)
+end
+
+function readstat_insert_int16_value(writer, variable, value)
+    return ccall((:readstat_insert_int16_value, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cshort), writer, variable, value)
+end
+
+function readstat_insert_int8_value(writer, variable, value)
+    return ccall((:readstat_insert_int8_value, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cchar), writer, variable, value)
+end
+
+function readstat_insert_string_value(writer, variable, value)
+    return ccall((:readstat_insert_string_value, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Ptr{Cstring}), writer, variable, value)
+end
+
+function readstat_insert_missing_value(writer, variable)
+    return ccall((:readstat_insert_missing_value, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}), writer, variable)
+end

From d122d22f1555ab9ddb8846728b74dcc333cc75aa Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 12:47:16 +0200
Subject: [PATCH 14/22] add variable insertion and string length logic

---
 src/C_interface.jl |  6 +++++-
 src/ReadStat.jl    | 35 +++++++++++++++++++++++++++++++----
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/src/C_interface.jl b/src/C_interface.jl
index f7fc357..c486ff9 100644
--- a/src/C_interface.jl
+++ b/src/C_interface.jl
@@ -129,9 +129,13 @@ function readstat_insert_int8_value(writer, variable, value)
 end
 
 function readstat_insert_string_value(writer, variable, value)
-    return ccall((:readstat_insert_string_value, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Ptr{Cstring}), writer, variable, value)
+    return ccall((:readstat_insert_string_value, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}, Cstring), writer, variable, value)
 end
 
 function readstat_insert_missing_value(writer, variable)
     return ccall((:readstat_insert_missing_value, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}), writer, variable)
 end
+
+function readstat_add_variable(writer, name, type, width)
+    return ccall((:readstat_add_variable, libreadstat), Ptr{Nothing}, (Ptr{Nothing}, Cstring, Cint, Cint), writer, name, type, width)
+end
\ No newline at end of file
diff --git a/src/ReadStat.jl b/src/ReadStat.jl
index fa38531..afaa925 100644
--- a/src/ReadStat.jl
+++ b/src/ReadStat.jl
@@ -321,12 +321,13 @@ function write_data_file(filetype::Val, io::IO, source)
     schema = Tables.schema(rows)
     variables_array = []
 
-    variables_array = map(Tables.columnnames(source)) do column_name
-        return ccall((:readstat_add_variable, libreadstat), 
-            Ptr{Nothing}, (Ptr{Nothing}, Cstring, Cint, Cint), 
-            writer, String(column_name), READSTAT_TYPE_DOUBLE, Cint(0)) # TODO: know width
+    variables_array = map(schema.names, schema.types) do column_name, column_type
+        readstat_type, storage_width = readstat_column_type_and_width(source, column_name, nonmissingtype(column_type))
+        return add_variable!(writer, column_name, readstat_type, storage_width)
         # readstat_variable_set_label(variable, String(field)) TODO: label for a variable
     end
+
+
     
     readstat_begin_writing(writer, filetype, io, length(rows))
 
@@ -342,7 +343,33 @@ function write_data_file(filetype::Val, io::IO, source)
     ccall((:readstat_writer_free, libreadstat), Cvoid, (Ptr{Nothing},), writer)
 end
 
+readstat_column_type_and_width(_, _, other_type) = error("Cannot handle column with element type $other_type. Is this type supported by ReadStat?")
+readstat_column_type_and_width(_, _, ::Type{Float64}) = READSTAT_TYPE_DOUBLE, 0
+readstat_column_type_and_width(_, _, ::Type{Float32}) = READSTAT_TYPE_FLOAT, 0
+readstat_column_type_and_width(_, _, ::Type{Int32}) = READSTAT_TYPE_INT32, 0
+readstat_column_type_and_width(_, _, ::Type{Int16}) = READSTAT_TYPE_INT16, 0
+readstat_column_type_and_width(_, _, ::Type{Int8}) = READSTAT_TYPE_CHAR, 0
+function readstat_column_type_and_width(source, colname, ::Type{String})
+    col = Tables.getcolumn(source, colname)
+    maxlen = maximum(col) do str
+        str === missing ? 0 : ncodeunits(str)
+    end
+    if maxlen >= 2045 # maximum length of normal strings
+        return READSTAT_TYPE_LONG_STRING, 0
+    else
+        return READSTAT_TYPE_STRING, maxlen
+    end
+end
+
+add_variable!(writer, name, type, width = 0) = readstat_add_variable(writer, name, type, width)
+
 insert_value!(writer, variable, value::Float64) = readstat_insert_double_value(writer, variable, value)
+insert_value!(writer, variable, value::Float32) = readstat_insert_float_value(writer, variable, value)
+insert_value!(writer, variable, ::Missing) = readstat_insert_missing_value(writer, variable)
+insert_value!(writer, variable, value::Int8) = readstat_insert_int8_value(writer, variable, value)
+insert_value!(writer, variable, value::Int16) = readstat_insert_int16_value(writer, variable, value)
+insert_value!(writer, variable, value::Int32) = readstat_insert_int32_value(writer, variable, value)
+insert_value!(writer, variable, value::AbstractString) = readstat_insert_string_value(writer, variable, value)
 
 read_dta(filename::AbstractString) = read_data_file(filename, Val(:dta))
 read_sav(filename::AbstractString) = read_data_file(filename, Val(:sav))

From 39c475199f3206257bc599f29a23e7a7b2c5bd02 Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 12:47:25 +0200
Subject: [PATCH 15/22] more tests

---
 test/runtests.jl | 78 ++++++++++++++++++++++++++++--------------------
 1 file changed, 45 insertions(+), 33 deletions(-)

diff --git a/test/runtests.jl b/test/runtests.jl
index d37f754..75ae76e 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -8,41 +8,53 @@ if isdir(testdir)
 end
 mkdir(testdir)
 
-@testset "ReadStat: $ext files" for (reader, writer, ext) in
-    ((read_dta, write_dta, "dta"),
-     (read_sav, write_sav, "sav"),
-     (read_sas7bdat, write_sas7bdat, "sas7bdat"),
-     (read_xport, write_xport, "xpt"))
+@testset "ReadStat" begin
+    @testset "$ext files" for (reader, writer, ext) in
+        ((read_dta, write_dta, "dta"),
+        (read_sav, write_sav, "sav"),
+        (read_sas7bdat, write_sas7bdat, "sas7bdat"),
+        (read_xport, write_xport, "xpt"))
 
-    @testset "Reading" begin
-        dtafile = joinpath(@__DIR__, "types.$ext")
-        rsdf = reader(dtafile)
-        data = rsdf.data
+        @testset "Reading" begin
+            dtafile = joinpath(@__DIR__, "types.$ext")
+            rsdf = reader(dtafile)
+            data = rsdf.data
 
-        @test length(data) == 6
-        @test rsdf.headers == [:vfloat, :vdouble, :vlong, :vint, :vbyte, :vstring]
-        @test data[1] == DataValueArray{Float32}([3.14, 7., NA])
-        @test data[2] == DataValueArray{Float64}([3.14, 7., NA])
-        @test data[3] == DataValueArray{Int32}([2, 7, NA])
-        @test data[4] == DataValueArray{Int16}([2, 7, NA])
-        @test data[5] == DataValueArray{Int8}([2, 7., NA])
-        @test data[6] == DataValueArray{String}(["2", "7", ""])
-    end
+            @test length(data) == 6
+            @test rsdf.headers == [:vfloat, :vdouble, :vlong, :vint, :vbyte, :vstring]
+            @test data[1] == DataValueArray{Float32}([3.14, 7., NA])
+            @test data[2] == DataValueArray{Float64}([3.14, 7., NA])
+            @test data[3] == DataValueArray{Int32}([2, 7, NA])
+            @test data[4] == DataValueArray{Int16}([2, 7, NA])
+            @test data[5] == DataValueArray{Int8}([2, 7., NA])
+            @test data[6] == DataValueArray{String}(["2", "7", ""])
+
+            @test rsdf.types == [Float32, Float64, Int32, Int16, Int8, String]
+        end
+
+        @testset "Writing" begin
+            data = (
+                vdouble = [3.14, 7., missing],
+                vfloat = [3.14f0, 7.f0, missing],
+                vint32 = [Int32(2), Int32(7), missing],
+                vint16 = [Int16(2), Int16(7), missing],
+                vint8 = [Int8(2), Int8(7), missing],
+                vstring = ["2", "7", ""],
+            )
+            filepath = joinpath(testdir, "testwrite.$ext")
+            writer(filepath, data)
+            rsdf = reader(filepath)
+            data_read = rsdf.data
+            @test length(data_read) == length(data)
+            @test rsdf.headers == collect(keys(data))
+            @test rsdf.types == [Float64, Float32, Int32, Int16, Int8, String]
 
-    @testset "Writing" begin
-        data = (
-            vdouble = [3.14, 7.],
-            # vfloat = [3.14f0, 7.f0, missing],
-            # vlong = [2, 7, missing],
-            # vint = [Int16(2), Int16(7), missing],
-            # vbyte = [Int8(2), Int8(7), missing],
-            # vstring = ["2", "7", ""],
-        )
-        filepath = joinpath(testdir, "testwrite.$ext")
-        writer(filepath, data)
-        rsdf = reader(filepath)
-        data_read = rsdf.data
-        @test length(data_read) == length(data)
-        @test rsdf.headers == [:vdouble]
+            same_value(a::DataValue, b) = a.hasvalue ? get(a) === b : b === missing
+            same_value(a::DataValue{String}, b::String) = a.hasvalue && get(a) == b
+        
+            @test all(zip(data_read, values(data))) do (col_read, col)
+                all(Base.splat(same_value), zip(col_read, col))
+            end
+        end
     end
 end

From dc8998b790428567410abbd6985ef730637c7b40 Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 12:51:53 +0200
Subject: [PATCH 16/22] remove duplicated line

---
 src/ReadStat.jl | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/src/ReadStat.jl b/src/ReadStat.jl
index afaa925..f4b50e8 100644
--- a/src/ReadStat.jl
+++ b/src/ReadStat.jl
@@ -282,10 +282,6 @@ function error_message(retval::Integer)
     unsafe_string(ccall((:readstat_error_message, libreadstat), Ptr{Cchar}, (Cint,), retval))
 end
 
-function error_message(retval::Integer)
-    unsafe_string(ccall((:readstat_error_message, libreadstat), Ptr{Cchar}, (Cint,), retval))
-end
-
 function parse_data_file!(ds::ReadStatDataFrame, parser::Ptr{Nothing}, filename::AbstractString, filetype::Val)
     retval = readstat_parse(filename, filetype, parser, ds)
     readstat_parser_free(parser)

From 85e781c1728e9f8aadfee1813bf573b2a13d6ce1 Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 13:16:54 +0200
Subject: [PATCH 17/22] adjust tests to reflect type limitations in output
 formats

---
 test/runtests.jl | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/test/runtests.jl b/test/runtests.jl
index 75ae76e..52fe636 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -28,8 +28,6 @@ mkdir(testdir)
             @test data[4] == DataValueArray{Int16}([2, 7, NA])
             @test data[5] == DataValueArray{Int8}([2, 7., NA])
             @test data[6] == DataValueArray{String}(["2", "7", ""])
-
-            @test rsdf.types == [Float32, Float64, Int32, Int16, Int8, String]
         end
 
         @testset "Writing" begin
@@ -39,7 +37,7 @@ mkdir(testdir)
                 vint32 = [Int32(2), Int32(7), missing],
                 vint16 = [Int16(2), Int16(7), missing],
                 vint8 = [Int8(2), Int8(7), missing],
-                vstring = ["2", "7", ""],
+                vstring = ["2", "7", missing],
             )
             filepath = joinpath(testdir, "testwrite.$ext")
             writer(filepath, data)
@@ -47,10 +45,11 @@ mkdir(testdir)
             data_read = rsdf.data
             @test length(data_read) == length(data)
             @test rsdf.headers == collect(keys(data))
-            @test rsdf.types == [Float64, Float32, Int32, Int16, Int8, String]
 
-            same_value(a::DataValue, b) = a.hasvalue ? get(a) === b : b === missing
-            same_value(a::DataValue{String}, b::String) = a.hasvalue && get(a) == b
+            same_value(a::DataValue, b) = a.hasvalue && get(a) == b
+            same_value(a::DataValue, b::Missing) = !a.hasvalue
+            # missing String appears to be read back in as the empty string ""
+            same_value(a::DataValue{String}, b::Missing) = a.hasvalue && get(a) == ""
         
             @test all(zip(data_read, values(data))) do (col_read, col)
                 all(Base.splat(same_value), zip(col_read, col))

From 810aab61e23a852314e764f9a5d318eac58f38b6 Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 13:17:21 +0200
Subject: [PATCH 18/22] add comment

---
 test/runtests.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/runtests.jl b/test/runtests.jl
index 52fe636..70f1a0e 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -46,7 +46,7 @@ mkdir(testdir)
             @test length(data_read) == length(data)
             @test rsdf.headers == collect(keys(data))
 
-            same_value(a::DataValue, b) = a.hasvalue && get(a) == b
+            same_value(a::DataValue, b) = a.hasvalue && get(a) == b # SAS and SPSS only support Float64 and String, so we can't test ===
             same_value(a::DataValue, b::Missing) = !a.hasvalue
             # missing String appears to be read back in as the empty string ""
             same_value(a::DataValue{String}, b::Missing) = a.hasvalue && get(a) == ""

From 40e93f6916a34a2e73b1af56815f70f934e892cf Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 13:25:13 +0200
Subject: [PATCH 19/22] throw for uninferred table schema

---
 src/ReadStat.jl | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/ReadStat.jl b/src/ReadStat.jl
index f4b50e8..c26a333 100644
--- a/src/ReadStat.jl
+++ b/src/ReadStat.jl
@@ -315,6 +315,9 @@ function write_data_file(filetype::Val, io::IO, source)
 
     rows = Tables.rows(source)
     schema = Tables.schema(rows)
+    if schema === nothing
+        error("Could not determine table schema for data source.")
+    end
     variables_array = []
 
     variables_array = map(schema.names, schema.types) do column_name, column_type

From 117465eb38e689ab8777b4f4ad1445c850a96d66 Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 13:25:20 +0200
Subject: [PATCH 20/22] add broken long string test

---
 test/runtests.jl | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/test/runtests.jl b/test/runtests.jl
index 70f1a0e..5bdd7a0 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -55,5 +55,14 @@ mkdir(testdir)
                 all(Base.splat(same_value), zip(col_read, col))
             end
         end
+
+        @testset "Long string" begin
+            data = (x = ["a" ^ 2046, missing],)
+            filepath = joinpath(testdir, "testwrite_longstring.$ext")
+            writer(filepath, data)
+            rsdf = reader(filepath)
+            data_read = rsdf.data
+            @test_broken get(data_read[1][1]) == "a" ^ 2046
+        end
     end
 end

From 26dfb360773294cc7a981eba003644eb6db11ed9 Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 13:31:51 +0200
Subject: [PATCH 21/22] pass file label via kwargs

---
 src/ReadStat.jl | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/src/ReadStat.jl b/src/ReadStat.jl
index c26a333..598aac1 100644
--- a/src/ReadStat.jl
+++ b/src/ReadStat.jl
@@ -295,7 +295,7 @@ function handle_write!(data::Ptr{UInt8}, len::Cint, ctx::Ptr)
     return len
  end
 
-function Writer(source; file_label="File Label")
+function Writer(; file_label)
     writer = ccall((:readstat_writer_init, libreadstat), Ptr{Nothing}, ())
     write_bytes = @cfunction(handle_write!, Cint, (Ptr{UInt8}, Cint, Ptr{Nothing}))
     ccall((:readstat_set_data_writer, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}), writer, write_bytes)
@@ -303,15 +303,15 @@ function Writer(source; file_label="File Label")
     return writer
 end
 
-function write_data_file(filename::AbstractString, filetype::Val, source) 
+function write_data_file(filename::AbstractString, filetype::Val, source; kwargs...) 
     io = open(filename, "w")
-    write_data_file(filetype::Val, io, source)
+    write_data_file(filetype::Val, io, source; kwargs...)
     close(io)
 end
 
 
-function write_data_file(filetype::Val, io::IO, source)
-    writer = Writer(source)
+function write_data_file(filetype::Val, io::IO, source; file_label = "")
+    writer = Writer(; file_label = file_label)
 
     rows = Tables.rows(source)
     schema = Tables.schema(rows)
@@ -326,8 +326,6 @@ function write_data_file(filetype::Val, io::IO, source)
         # readstat_variable_set_label(variable, String(field)) TODO: label for a variable
     end
 
-
-    
     readstat_begin_writing(writer, filetype, io, length(rows))
 
     for row in rows
@@ -376,10 +374,10 @@ read_por(filename::AbstractString) = read_data_file(filename, Val(:por))
 read_sas7bdat(filename::AbstractString) = read_data_file(filename, Val(:sas7bdat))
 read_xport(filename::AbstractString) = read_data_file(filename, Val(:xport))
 
-write_dta(filename::AbstractString, source) = write_data_file(filename, Val(:dta), source)
-write_sav(filename::AbstractString, source) = write_data_file(filename, Val(:sav), source)
-write_por(filename::AbstractString, source) = write_data_file(filename, Val(:por), source)
-write_sas7bdat(filename::AbstractString, source) = write_data_file(filename, Val(:sas7bdat), source)
-write_xport(filename::AbstractString, source) = write_data_file(filename, Val(:xport), source)
+write_dta(filename::AbstractString, source; kwargs...) = write_data_file(filename, Val(:dta), source; kwargs...)
+write_sav(filename::AbstractString, source; kwargs...) = write_data_file(filename, Val(:sav), source; kwargs...)
+write_por(filename::AbstractString, source; kwargs...) = write_data_file(filename, Val(:por), source; kwargs...)
+write_sas7bdat(filename::AbstractString, source; kwargs...) = write_data_file(filename, Val(:sas7bdat), source; kwargs...)
+write_xport(filename::AbstractString, source; kwargs...) = write_data_file(filename, Val(:xport), source; kwargs...)
 
 end #module ReadStat

From b2c48c4c65be6f5ffbf9b480781d2759ae022559 Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Mon, 1 Aug 2022 13:35:25 +0200
Subject: [PATCH 22/22] add filelabel test

---
 src/ReadStat.jl  | 8 ++++----
 test/runtests.jl | 8 ++++++++
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/ReadStat.jl b/src/ReadStat.jl
index 598aac1..5de462a 100644
--- a/src/ReadStat.jl
+++ b/src/ReadStat.jl
@@ -295,11 +295,11 @@ function handle_write!(data::Ptr{UInt8}, len::Cint, ctx::Ptr)
     return len
  end
 
-function Writer(; file_label)
+function Writer(; filelabel)
     writer = ccall((:readstat_writer_init, libreadstat), Ptr{Nothing}, ())
     write_bytes = @cfunction(handle_write!, Cint, (Ptr{UInt8}, Cint, Ptr{Nothing}))
     ccall((:readstat_set_data_writer, libreadstat), Int, (Ptr{Nothing}, Ptr{Nothing}), writer, write_bytes)
-    ccall((:readstat_writer_set_file_label, libreadstat), Cvoid, (Ptr{Nothing}, Cstring), writer, file_label)
+    ccall((:readstat_writer_set_file_label, libreadstat), Cvoid, (Ptr{Nothing}, Cstring), writer, filelabel)
     return writer
 end
 
@@ -310,8 +310,8 @@ function write_data_file(filename::AbstractString, filetype::Val, source; kwargs
 end
 
 
-function write_data_file(filetype::Val, io::IO, source; file_label = "")
-    writer = Writer(; file_label = file_label)
+function write_data_file(filetype::Val, io::IO, source; filelabel = "")
+    writer = Writer(; filelabel = filelabel)
 
     rows = Tables.rows(source)
     schema = Tables.schema(rows)
diff --git a/test/runtests.jl b/test/runtests.jl
index 5bdd7a0..09344fa 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -64,5 +64,13 @@ mkdir(testdir)
             data_read = rsdf.data
             @test_broken get(data_read[1][1]) == "a" ^ 2046
         end
+
+        @testset "File metadata" begin
+            data = (a = Int32[1, 2, 3],)
+            filepath = joinpath(testdir, "testwrite_file_metadata.$ext")
+            writer(filepath, data; filelabel = "Test label")
+            rsdf = reader(filepath)
+            @test rsdf.filelabel == "Test label"
+        end
     end
 end