Update generated scripts to match pip installed scripts (#359)

* Update generated scripts to match pip installed scripts

* escape some backslashed

* Compute import name outside of parse_entry_point

* Fix docstring of parse_entry_point

Co-authored-by: Thomas Kluyver <takowl@gmail.com>

flit/install.py

@@ -172,12 +172,14 @@ def _auto_user(self, python):
     def install_scripts(self, script_defs, scripts_dir):
         for name, ep in script_defs.items():
             module, func = common.parse_entry_point(ep)
+            import_name = func.split('.')[0]
             script_file = pathlib.Path(scripts_dir) / name
             log.info('Writing script to %s', script_file)
             with script_file.open('w', encoding='utf-8') as f:
                 f.write(common.script_template.format(
                     interpreter=self.python,
                     module=module,
+                    import_name=import_name,
                     func=func
                 ))
             script_file.chmod(0o755)

flit_core/flit_core/common.py

@@ -209,9 +209,13 @@ def check_version(version):
 
 script_template = """\
 #!{interpreter}
-from {module} import {func}
+# -*- coding: utf-8 -*-
+import re
+import sys
+from {module} import {import_name}
 if __name__ == '__main__':
-    {func}()
+    sys.argv[0] = re.sub(r'(-script\\.pyw|\\.exe)?$', '', sys.argv[0])
+    sys.exit({func}())
 """
 
 def parse_entry_point(ep):
@@ -223,8 +227,9 @@ def parse_entry_point(ep):
         raise ValueError("Invalid entry point (no ':'): %r" % ep)
     mod, func = ep.split(':')
 
-    if not func.isidentifier():
-        raise ValueError("Invalid entry point: %r is not an identifier" % func)
+    for piece in func.split('.'):
+        if not piece.isidentifier():
+            raise ValueError("Invalid entry point: %r is not an identifier" % piece)
     for piece in mod.split('.'):
         if not piece.isidentifier():
             raise ValueError("Invalid entry point: %r is not a module path" % piece)