bpo-40939: Rename PyPegen* functions to PyParser* (GH-21016)

Rename PyPegen* functions to PyParser*, so that we can remove the
old set of PyParser* functions that were using the old parser.

diff --git a/Include/Python.h b/Include/Python.h
index dcd0a57..57f71d4 100644
--- a/Include/Python.h
+++ b/Include/Python.h
@@ -141,6 +141,7 @@
 #include "modsupport.h"
 #include "compile.h"
 #include "pythonrun.h"
+#include "parser_interface.h"
 #include "pylifecycle.h"
 #include "ceval.h"
 #include "sysmodule.h"
diff --git a/Include/internal/pegen_interface.h b/Include/internal/pegen_interface.h
deleted file mode 100644
index ee4c77e..0000000
--- a/Include/internal/pegen_interface.h
+++ /dev/null
@@ -1,46 +0,0 @@
-#ifndef Py_PEGENINTERFACE
-#define Py_PEGENINTERFACE
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#ifndef Py_BUILD_CORE
-#  error "this header requires Py_BUILD_CORE define"
-#endif
-
-#include "Python.h"
-#include "Python-ast.h"
-
-PyAPI_FUNC(mod_ty) PyPegen_ASTFromString(
-    const char *str,
-    const char *filename,
-    int mode,
-    PyCompilerFlags *flags,
-    PyArena *arena);
-PyAPI_FUNC(mod_ty) PyPegen_ASTFromStringObject(
-    const char *str,
-    PyObject* filename,
-    int mode,
-    PyCompilerFlags *flags,
-    PyArena *arena);
-PyAPI_FUNC(mod_ty) PyPegen_ASTFromFileObject(
-    FILE *fp,
-    PyObject *filename_ob,
-    int mode,
-    const char *enc,
-    const char *ps1,
-    const char *ps2,
-    PyCompilerFlags *flags,
-    int *errcode,
-    PyArena *arena);
-PyAPI_FUNC(mod_ty) PyPegen_ASTFromFilename(
-    const char *filename,
-    int mode,
-    PyCompilerFlags *flags,
-    PyArena *arena);
-
-
-#ifdef __cplusplus
-}
-#endif
-#endif /* !Py_PEGENINTERFACE*/
diff --git a/Include/parser_interface.h b/Include/parser_interface.h
new file mode 100644
index 0000000..1c6576d
--- /dev/null
+++ b/Include/parser_interface.h
@@ -0,0 +1,52 @@
+#ifndef Py_PEGENINTERFACE
+#define Py_PEGENINTERFACE
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "Python.h"
+
+#ifndef Py_LIMITED_API
+PyAPI_FUNC(struct _mod *) PyParser_ASTFromString(
+    const char *str,
+    const char *filename,
+    int mode,
+    PyCompilerFlags *flags,
+    PyArena *arena);
+PyAPI_FUNC(struct _mod *) PyParser_ASTFromStringObject(
+    const char *str,
+    PyObject* filename,
+    int mode,
+    PyCompilerFlags *flags,
+    PyArena *arena);
+PyAPI_FUNC(struct _mod *) PyParser_ASTFromFile(
+    FILE *fp,
+    const char *filename,
+    const char* enc,
+    int mode,
+    const char *ps1,
+    const char *ps2,
+    PyCompilerFlags *flags,
+    int *errcode,
+    PyArena *arena);
+PyAPI_FUNC(struct _mod *) PyParser_ASTFromFileObject(
+    FILE *fp,
+    PyObject *filename_ob,
+    const char *enc,
+    int mode,
+    const char *ps1,
+    const char *ps2,
+    PyCompilerFlags *flags,
+    int *errcode,
+    PyArena *arena);
+PyAPI_FUNC(struct _mod *) PyParser_ASTFromFilename(
+    const char *filename,
+    int mode,
+    PyCompilerFlags *flags,
+    PyArena *arena);
+#endif /* !Py_LIMITED_API */
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !Py_PEGENINTERFACE */
diff --git a/Include/pythonrun.h b/Include/pythonrun.h
index 46091e0..d43734b 100644
--- a/Include/pythonrun.h
+++ b/Include/pythonrun.h
@@ -32,57 +32,7 @@
     const char *filename,       /* decoded from the filesystem encoding */
     PyCompilerFlags *flags);
 
-PyAPI_FUNC(struct _mod *) PyParser_ASTFromString(
-    const char *s,
-    const char *filename,       /* decoded from the filesystem encoding */
-    int start,
-    PyCompilerFlags *flags,
-    PyArena *arena);
-PyAPI_FUNC(struct _mod *) PyParser_ASTFromStringObject(
-    const char *s,
-    PyObject *filename,
-    int start,
-    PyCompilerFlags *flags,
-    PyArena *arena);
-PyAPI_FUNC(struct _mod *) PyParser_ASTFromFile(
-    FILE *fp,
-    const char *filename,       /* decoded from the filesystem encoding */
-    const char* enc,
-    int start,
-    const char *ps1,
-    const char *ps2,
-    PyCompilerFlags *flags,
-    int *errcode,
-    PyArena *arena);
-PyAPI_FUNC(struct _mod *) PyParser_ASTFromFileObject(
-    FILE *fp,
-    PyObject *filename,
-    const char* enc,
-    int start,
-    const char *ps1,
-    const char *ps2,
-    PyCompilerFlags *flags,
-    int *errcode,
-    PyArena *arena);
-#endif
 
-#ifndef PyParser_SimpleParseString
-#define PyParser_SimpleParseString(S, B) \
-    PyParser_SimpleParseStringFlags(S, B, 0)
-#define PyParser_SimpleParseFile(FP, S, B) \
-    PyParser_SimpleParseFileFlags(FP, S, B, 0)
-#endif
-PyAPI_FUNC(struct _node *) PyParser_SimpleParseStringFlags(const char *, int,
-                                                           int);
-#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000
-PyAPI_FUNC(struct _node *) PyParser_SimpleParseStringFlagsFilename(const char *,
-                                                                   const char *,
-                                                                   int, int);
-#endif
-PyAPI_FUNC(struct _node *) PyParser_SimpleParseFileFlags(FILE *, const char *,
-                                                         int, int);
-
-#ifndef Py_LIMITED_API
 PyAPI_FUNC(PyObject *) PyRun_StringFlags(const char *, int, PyObject *,
                                          PyObject *, PyCompilerFlags *);
 
diff --git a/Makefile.pre.in b/Makefile.pre.in
index fc6dc43..24dddcf 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -307,7 +307,7 @@
 
 
 PEGEN_HEADERS= \
-		$(srcdir)/Include/internal/pegen_interface.h \
+		$(srcdir)/Include/parser_interface.h \
 		$(srcdir)/Parser/pegen.h \
 		$(srcdir)/Parser/string_parser.h
 
diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-06-20-19-27-47.bpo-40939.jxJ4yn.rst b/Misc/NEWS.d/next/Core and Builtins/2020-06-20-19-27-47.bpo-40939.jxJ4yn.rst
new file mode 100644
index 0000000..7024dfe
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2020-06-20-19-27-47.bpo-40939.jxJ4yn.rst
@@ -0,0 +1 @@
+Rename `PyPegen*` functions to `PyParser*`, so that we can remove the old set of `PyParser*` functions that were using the old parser, but keep everything backwards-compatible.
\ No newline at end of file
diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj
index 0f9110e..fc99d77 100644
--- a/PCbuild/pythoncore.vcxproj
+++ b/PCbuild/pythoncore.vcxproj
@@ -162,7 +162,6 @@
     <ClInclude Include="..\Include\funcobject.h" />
     <ClInclude Include="..\Include\genobject.h" />
     <ClInclude Include="..\Include\import.h" />
-    <ClInclude Include="..\Include\internal\pegen_interface.h" />
     <ClInclude Include="..\Include\internal\pycore_abstract.h" />
     <ClInclude Include="..\Include\internal\pycore_accu.h" />
     <ClInclude Include="..\Include\internal\pycore_atomic.h" />
@@ -213,6 +212,7 @@
     <ClInclude Include="..\Include\osdefs.h" />
     <ClInclude Include="..\Include\osmodule.h" />
     <ClInclude Include="..\Include\patchlevel.h" />
+    <ClInclude Include="..\Include\parser_interface.h" />
     <ClInclude Include="..\Include\picklebufobject.h" />
     <ClInclude Include="..\Include\py_curses.h" />
     <ClInclude Include="..\Include\pyarena.h" />
diff --git a/Parser/peg_api.c b/Parser/peg_api.c
index b947c78..8381d5e 100644
--- a/Parser/peg_api.c
+++ b/Parser/peg_api.c
@@ -1,23 +1,23 @@
-#include "pegen_interface.h"
+#include "parser_interface.h"
 
 #include "tokenizer.h"
 #include "pegen.h"
 
 mod_ty
-PyPegen_ASTFromString(const char *str, const char *filename, int mode,
+PyParser_ASTFromString(const char *str, const char *filename, int mode,
                       PyCompilerFlags *flags, PyArena *arena)
 {
     PyObject *filename_ob = PyUnicode_FromString(filename);
     if (filename_ob == NULL) {
         return NULL;
     }
-    mod_ty result = PyPegen_ASTFromStringObject(str, filename_ob, mode, flags, arena);
+    mod_ty result = PyParser_ASTFromStringObject(str, filename_ob, mode, flags, arena);
     Py_XDECREF(filename_ob);
     return result;
 }
 
 mod_ty
-PyPegen_ASTFromStringObject(const char *str, PyObject* filename, int mode,
+PyParser_ASTFromStringObject(const char *str, PyObject* filename, int mode,
                             PyCompilerFlags *flags, PyArena *arena)
 {
     if (PySys_Audit("compile", "yO", str, filename) < 0) {
@@ -29,7 +29,7 @@
 }
 
 mod_ty
-PyPegen_ASTFromFilename(const char *filename, int mode, PyCompilerFlags *flags, PyArena *arena)
+PyParser_ASTFromFilename(const char *filename, int mode, PyCompilerFlags *flags, PyArena *arena)
 {
     PyObject *filename_ob = PyUnicode_FromString(filename);
     if (filename_ob == NULL) {
@@ -42,8 +42,23 @@
 }
 
 mod_ty
-PyPegen_ASTFromFileObject(FILE *fp, PyObject *filename_ob, int mode,
-                          const char *enc, const char *ps1, const char* ps2,
+PyParser_ASTFromFile(FILE *fp, const char *filename, const char *enc,
+                    int mode, const char *ps1, const char* ps2,
+                    PyCompilerFlags *flags, int *errcode, PyArena *arena)
+{
+    PyObject *filename_ob = PyUnicode_FromString(filename);
+    if (filename_ob == NULL) {
+        return NULL;
+    }
+    mod_ty result = PyParser_ASTFromFileObject(fp, filename_ob, enc, mode,
+                                              ps1, ps2, flags, errcode, arena);
+    Py_XDECREF(filename_ob);
+    return result;
+}
+
+mod_ty
+PyParser_ASTFromFileObject(FILE *fp, PyObject *filename_ob, const char *enc,
+                          int mode, const char *ps1, const char* ps2,
                           PyCompilerFlags *flags, int *errcode, PyArena *arena)
 {
     if (PySys_Audit("compile", "OO", Py_None, filename_ob) < 0) {
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 04fad04..ff80103 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -26,7 +26,7 @@
 #include "symtable.h"             // PySymtable_BuildObject()
 #include "marshal.h"              // PyMarshal_ReadLongFromFile()
 
-#include "pegen_interface.h"      // PyPegen_ASTFrom*
+#include "parser_interface.h"      // PyParser_ASTFrom*
 
 #ifdef MS_WINDOWS
 #  include "malloc.h"             // alloca()
@@ -205,8 +205,8 @@
         return -1;
     }
 
-    mod = PyPegen_ASTFromFileObject(fp, filename, Py_single_input,
-                                    enc, ps1, ps2, flags, &errcode, arena);
+    mod = PyParser_ASTFromFileObject(fp, filename, enc, Py_single_input,
+                                     ps1, ps2, flags, &errcode, arena);
 
     Py_XDECREF(v);
     Py_XDECREF(w);
@@ -1026,7 +1026,7 @@
     if (arena == NULL)
         return NULL;
 
-    mod = PyPegen_ASTFromStringObject(str, filename, start, flags, arena);
+    mod = PyParser_ASTFromStringObject(str, filename, start, flags, arena);
 
     if (mod != NULL)
         ret = run_mod(mod, filename, globals, locals, flags, arena);
@@ -1051,8 +1051,8 @@
     if (arena == NULL)
         goto exit;
 
-    mod = PyPegen_ASTFromFileObject(fp, filename, start, NULL, NULL, NULL,
-                                        flags, NULL, arena);
+    mod = PyParser_ASTFromFileObject(fp, filename, NULL, start, NULL, NULL,
+                                     flags, NULL, arena);
 
     if (closeit)
         fclose(fp);
@@ -1200,7 +1200,7 @@
     if (arena == NULL)
         return NULL;
 
-    mod = PyPegen_ASTFromStringObject(str, filename, start, flags, arena);
+    mod = PyParser_ASTFromStringObject(str, filename, start, flags, arena);
     if (mod == NULL) {
         PyArena_Free(arena);
         return NULL;
@@ -1303,7 +1303,7 @@
     if (arena == NULL)
         return NULL;
 
-    mod = PyPegen_ASTFromStringObject(str, filename, start, flags, arena);
+    mod = PyParser_ASTFromStringObject(str, filename, start, flags, arena);
     if (mod == NULL) {
         PyArena_Free(arena);
         return NULL;