Merge pull request RustPython#388 from veera83372/sys-doc

Added __doc__ for sys module

Author: windelbouwman

.gitignore

@@ -7,3 +7,4 @@ __pycache__
 .repl_history.txt
 .vscode
 wasm-pack.log
+.idea/

tests/snippets/sysmod_argv.py renamed to tests/snippets/sysmod.py

@@ -53,6 +53,75 @@ pub fn mk_module(ctx: &PyContext) -> PyObjectRef {
     let modules = ctx.new_dict();
 
     let sys_name = "sys";
+    let sys_doc = "This module provides access to some objects used or maintained by the
+interpreter and to functions that interact strongly with the interpreter.
+
+Dynamic objects:
+
+argv -- command line arguments; argv[0] is the script pathname if known
+path -- module search path; path[0] is the script directory, else ''
+modules -- dictionary of loaded modules
+
+displayhook -- called to show results in an interactive session
+excepthook -- called to handle any uncaught exception other than SystemExit
+  To customize printing in an interactive session or to install a custom
+  top-level exception handler, assign other functions to replace these.
+
+stdin -- standard input file object; used by input()
+stdout -- standard output file object; used by print()
+stderr -- standard error object; used for error messages
+  By assigning other file objects (or objects that behave like files)
+  to these, it is possible to redirect all of the interpreter's I/O.
+
+last_type -- type of last uncaught exception
+last_value -- value of last uncaught exception
+last_traceback -- traceback of last uncaught exception
+  These three are only available in an interactive session after a
+  traceback has been printed.
+
+Static objects:
+
+builtin_module_names -- tuple of module names built into this interpreter
+copyright -- copyright notice pertaining to this interpreter
+exec_prefix -- prefix used to find the machine-specific Python library
+executable -- absolute path of the executable binary of the Python interpreter
+float_info -- a struct sequence with information about the float implementation.
+float_repr_style -- string indicating the style of repr() output for floats
+hash_info -- a struct sequence with information about the hash algorithm.
+hexversion -- version information encoded as a single integer
+implementation -- Python implementation information.
+int_info -- a struct sequence with information about the int implementation.
+maxsize -- the largest supported length of containers.
+maxunicode -- the value of the largest Unicode code point
+platform -- platform identifier
+prefix -- prefix used to find the Python library
+thread_info -- a struct sequence with information about the thread implementation.
+version -- the version of this interpreter as a string
+version_info -- version information as a named tuple
+__stdin__ -- the original stdin; don't touch!
+__stdout__ -- the original stdout; don't touch!
+__stderr__ -- the original stderr; don't touch!
+__displayhook__ -- the original displayhook; don't touch!
+__excepthook__ -- the original excepthook; don't touch!
+
+Functions:
+
+displayhook() -- print an object to the screen, and save it in builtins._
+excepthook() -- print an exception and its traceback to sys.stderr
+exc_info() -- return thread-safe information about the current exception
+exit() -- exit the interpreter by raising SystemExit
+getdlopenflags() -- returns flags to be used for dlopen() calls
+getprofile() -- get the global profiling function
+getrefcount() -- return the reference count for an object (plus one :-)
+getrecursionlimit() -- return the max recursion depth for the interpreter
+getsizeof() -- return the size of an object in bytes
+gettrace() -- get the global debug tracing function
+setcheckinterval() -- control how often the interpreter checks for events
+setdlopenflags() -- set the flags to be used for dlopen() calls
+setprofile() -- set the global profiling function
+setrecursionlimit() -- set the max recursion depth for the interpreter
+settrace() -- set the global debug tracing function
+";
     let sys_mod = ctx.new_module(&sys_name, ctx.new_scope(None));
 
     ctx.set_item(&modules, sys_name, sys_mod.clone());
@@ -65,6 +134,7 @@ pub fn mk_module(ctx: &PyContext) -> PyObjectRef {
     ctx.set_item(&sys_mod, "path", path);
     ctx.set_item(&sys_mod, "ps1", ctx.new_str(">>>>> ".to_string()));
     ctx.set_item(&sys_mod, "ps2", ctx.new_str("..... ".to_string()));
+    ctx.set_item(&sys_mod, "__doc__", ctx.new_str(sys_doc.to_string()));
     ctx.set_item(&sys_mod, "_getframe", ctx.new_rustfunc(getframe));
 
     sys_mod