removed python compatibility (#7206)

* removed python compatibility

* add NEWS note

---------

Co-authored-by: Benjamin Schwendinger <benjaminschwe@gmail.com>

Author: badasahog

NEWS.md

@@ -8,6 +8,8 @@
 
 1. {data.table} now depends on R 3.5.0 (2018).
 
+2. pydatatable compatibility layer in `fread()` and `fwrite()` has been removed, [#7069](https://github.com/Rdatatable/data.table/issues/7069). Thanks @badasahog for the report and the PR.
+
 ### BUG FIXES
 
 1. `fread()` with `skip=0` and `(header=TRUE|FALSE)` no longer skips the first row when it has fewer fields than subsequent rows, [#7463](https://github.com/Rdatatable/data.table/issues/7463). Thanks @emayerhofer for the report and @ben-schwen for the fix.

src/fread.c

@@ -2502,10 +2502,8 @@ int freadMain(freadMainArgs _args)
         .threadn = me,
         .quoteRule = quoteRule,
         .stopTeam = &stopTeam,
-        #ifndef DTPY
         .nStringCols = nStringCols,
         .nNonStringCols = nNonStringCols
-        #endif
       };
       if ((rowSize8 && !ctx.buff8) || (rowSize4 && !ctx.buff4) || (rowSize1 && !ctx.buff1)) {
         stopTeam = true;

src/fread.h

@@ -5,16 +5,11 @@
 #include <stdlib.h>    // size_t
 #include <stdbool.h>   // bool
 #include "myomp.h"
-#ifdef DTPY
-  #include "py_fread.h"
-  #define ENC2NATIVE(s) (s)
-#else
-  #include "freadR.h"
-  extern cetype_t ienc;
-  // R's message functions only take C's char pointer not SEXP, where encoding info can't be stored
-  // so must convert the error message char to native encoding first in order to correctly display in R
-  #define ENC2NATIVE(s) translateChar(mkCharCE(s, ienc))
-#endif
+#include "freadR.h"
+extern cetype_t ienc;
+// R's message functions only take C's char pointer not SEXP, where encoding info can't be stored
+// so must convert the error message char to native encoding first in order to correctly display in R
+#define ENC2NATIVE(s) translateChar(mkCharCE(s, ienc))
 
 // Ordered hierarchy of types
 // Each of these corresponds to a parser; they must be ordered "preferentially", i.e., if the same
@@ -177,7 +172,7 @@ typedef struct freadMainArgs
   char _padding[1];
 
   // Any additional implementation-specific parameters.
-  FREAD_MAIN_ARGS_EXTRA_FIELDS
+  bool oldNoDateTime;
 
 } freadMainArgs;
 
@@ -223,8 +218,8 @@ typedef struct ThreadLocalFreadParsingContext
 
   int quoteRule;
 
-  // Any additional implementation-specific parameters.
-  FREAD_PUSH_BUFFERS_EXTRA_FIELDS
+  int nStringCols;
+  int nNonStringCols;
 
 } ThreadLocalFreadParsingContext;
 

src/freadR.h

@@ -7,13 +7,6 @@
 #include <Rinternals.h>
 #include "po.h"
 
-#define FREAD_MAIN_ARGS_EXTRA_FIELDS \
-  bool oldNoDateTime;
-
-#define FREAD_PUSH_BUFFERS_EXTRA_FIELDS \
-  int nStringCols; \
-  int nNonStringCols;
-
 // Before error() [or warning() with options(warn=2)] call freadCleanup() to close mmp and fix :
 //   http://stackoverflow.com/questions/18597123/fread-data-table-locks-files
 // However, msg has to be manually constructed first (rather than simply leaving construction to snprintf inside warning()

src/fwrite.h

@@ -1,17 +1,13 @@
-#ifdef DTPY
-  #include "py_fread.h"
-#else
-  #ifndef STRICT_R_HEADERS
-    #define STRICT_R_HEADERS
-  #endif
-  #include <R.h>
-  #include <Rinternals.h>  // for SEXP in writeList() prototype
-  #include "po.h"
-  #define STOP     error
-  #define DTPRINT  Rprintf
-  static char internal_error_buff[256] __attribute__((unused)); // todo: fix imports such that compiler warns correctly #6468
-  #define INTERNAL_STOP(...) do {snprintf(internal_error_buff, sizeof(internal_error_buff), __VA_ARGS__); error("%s %s: %s. %s", _("Internal error in"), __func__, internal_error_buff, _("Please report to the data.table issues tracker"));} while (0)
+#ifndef STRICT_R_HEADERS
+  #define STRICT_R_HEADERS
 #endif
+#include <R.h>
+#include <Rinternals.h>  // for SEXP in writeList() prototype
+#include "po.h"
+#define STOP     error
+#define DTPRINT  Rprintf
+static char internal_error_buff[256] __attribute__((unused)); // todo: fix imports such that compiler warns correctly #6468
+#define INTERNAL_STOP(...) do {snprintf(internal_error_buff, sizeof(internal_error_buff), __VA_ARGS__); error("%s %s: %s. %s", _("Internal error in"), __func__, internal_error_buff, _("Please report to the data.table issues tracker"));} while (0)
 
 typedef void writer_fun_t(const void *, int64_t, char **);