gh-111201: A new Python REPL (GH-111567)

Co-authored-by: Łukasz Langa <lukasz@langa.pl>
Co-authored-by: Marta Gómez Macías <mgmacias@google.com>
Co-authored-by: Lysandros Nikolaou <lisandrosnik@gmail.com>
Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

1 files changed, 68 insertions, 0 deletions

diff --git a/Lib/_pyrepl/_minimal_curses.py b/Lib/_pyrepl/_minimal_curses.py
new file mode 100644
index 00000000000..0757fb2c664
--- /dev/null
+++ b/Lib/_pyrepl/_minimal_curses.py
@@ -0,0 +1,68 @@
+"""Minimal '_curses' module, the low-level interface for curses module
+which is not meant to be used directly.
+
+Based on ctypes.  It's too incomplete to be really called '_curses', so
+to use it, you have to import it and stick it in sys.modules['_curses']
+manually.
+
+Note that there is also a built-in module _minimal_curses which will
+hide this one if compiled in.
+"""
+
+import ctypes
+import ctypes.util
+
+
+class error(Exception):
+    pass
+
+
+def _find_clib():
+    trylibs = ["ncursesw", "ncurses", "curses"]
+
+    for lib in trylibs:
+        path = ctypes.util.find_library(lib)
+        if path:
+            return path
+    raise ModuleNotFoundError("curses library not found", name="_pyrepl._minimal_curses")
+
+
+_clibpath = _find_clib()
+clib = ctypes.cdll.LoadLibrary(_clibpath)
+
+clib.setupterm.argtypes = [ctypes.c_char_p, ctypes.c_int, ctypes.POINTER(ctypes.c_int)]
+clib.setupterm.restype = ctypes.c_int
+
+clib.tigetstr.argtypes = [ctypes.c_char_p]
+clib.tigetstr.restype = ctypes.POINTER(ctypes.c_char)
+
+clib.tparm.argtypes = [ctypes.c_char_p] + 9 * [ctypes.c_int]  # type: ignore[operator]
+clib.tparm.restype = ctypes.c_char_p
+
+OK = 0
+ERR = -1
+
+# ____________________________________________________________
+
+
+def setupterm(termstr, fd):
+    err = ctypes.c_int(0)
+    result = clib.setupterm(termstr, fd, ctypes.byref(err))
+    if result == ERR:
+        raise error("setupterm() failed (err=%d)" % err.value)
+
+
+def tigetstr(cap):
+    if not isinstance(cap, bytes):
+        cap = cap.encode("ascii")
+    result = clib.tigetstr(cap)
+    if ctypes.cast(result, ctypes.c_void_p).value == ERR:
+        return None
+    return ctypes.cast(result, ctypes.c_char_p).value
+
+
+def tparm(str, i1=0, i2=0, i3=0, i4=0, i5=0, i6=0, i7=0, i8=0, i9=0):
+    result = clib.tparm(str, i1, i2, i3, i4, i5, i6, i7, i8, i9)
+    if result is None:
+        raise error("tparm() returned NULL")
+    return result