[devscripts] Create utils and refactor

devscripts/utils.py

@@ -0,0 +1,35 @@
+import argparse
+import functools
+
+
+def read_file(fname):
+    with open(fname, encoding='utf-8') as f:
+        return f.read()
+
+
+def write_file(fname, content):
+    with open(fname, 'w', encoding='utf-8') as f:
+        return f.write(content)
+
+
+# Get the version without importing the package
+def read_version(fname='yt_dlp/version.py'):
+    exec(compile(read_file(fname), fname, 'exec'))
+    return locals()['__version__']
+
+
+def get_filename_args(has_infile=False, default_outfile=None):
+    parser = argparse.ArgumentParser()
+    if has_infile:
+        parser.add_argument('infile', help='Input file')
+    kwargs = {'nargs': '?', 'default': default_outfile} if default_outfile else {}
+    parser.add_argument('outfile', **kwargs, help='Output file')
+
+    opts = parser.parse_args()
+    if has_infile:
+        return opts.infile, opts.outfile
+    return opts.outfile
+
+
+def compose_functions(*functions):
+    return lambda x: functools.reduce(lambda y, f: f(y), functions, x)