1"""CallTips.py - An IDLE Extension to Jog Your Memory
2
3Call Tips are floating windows which display function, class, and method
4parameter and docstring information when you type an opening parenthesis, and
5which disappear when you type a closing parenthesis.
6
7"""
8import __main__
9import re
10import sys
11import textwrap
12import types
13
14from idlelib import CallTipWindow
15from idlelib.HyperParser import HyperParser
16
17
18class CallTips:
19
20    menudefs = [
21        ('edit', [
22            ("Show call tip", "<<force-open-calltip>>"),
23        ])
24    ]
25
26    def __init__(self, editwin=None):
27        if editwin is None:  # subprocess and test
28            self.editwin = None
29            return
30        self.editwin = editwin
31        self.text = editwin.text
32        self.calltip = None
33        self._make_calltip_window = self._make_tk_calltip_window
34
35    def close(self):
36        self._make_calltip_window = None
37
38    def _make_tk_calltip_window(self):
39        # See __init__ for usage
40        return CallTipWindow.CallTip(self.text)
41
42    def _remove_calltip_window(self, event=None):
43        if self.calltip:
44            self.calltip.hidetip()
45            self.calltip = None
46
47    def force_open_calltip_event(self, event):
48        """Happens when the user really wants to open a CallTip, even if a
49        function call is needed.
50        """
51        self.open_calltip(True)
52
53    def try_open_calltip_event(self, event):
54        """Happens when it would be nice to open a CallTip, but not really
55        necessary, for example after an opening bracket, so function calls
56        won't be made.
57        """
58        self.open_calltip(False)
59
60    def refresh_calltip_event(self, event):
61        """If there is already a calltip window, check if it is still needed,
62        and if so, reload it.
63        """
64        if self.calltip and self.calltip.is_active():
65            self.open_calltip(False)
66
67    def open_calltip(self, evalfuncs):
68        self._remove_calltip_window()
69
70        hp = HyperParser(self.editwin, "insert")
71        sur_paren = hp.get_surrounding_brackets('(')
72        if not sur_paren:
73            return
74        hp.set_index(sur_paren[0])
75        expression = hp.get_expression()
76        if not expression or (not evalfuncs and expression.find('(') != -1):
77            return
78        arg_text = self.fetch_tip(expression)
79        if not arg_text:
80            return
81        self.calltip = self._make_calltip_window()
82        self.calltip.showtip(arg_text, sur_paren[0], sur_paren[1])
83
84    def fetch_tip(self, expression):
85        """Return the argument list and docstring of a function or class
86
87        If there is a Python subprocess, get the calltip there.  Otherwise,
88        either fetch_tip() is running in the subprocess itself or it was called
89        in an IDLE EditorWindow before any script had been run.
90
91        The subprocess environment is that of the most recently run script.  If
92        two unrelated modules are being edited some calltips in the current
93        module may be inoperative if the module was not the last to run.
94
95        To find methods, fetch_tip must be fed a fully qualified name.
96
97        """
98        try:
99            rpcclt = self.editwin.flist.pyshell.interp.rpcclt
100        except AttributeError:
101            rpcclt = None
102        if rpcclt:
103            return rpcclt.remotecall("exec", "get_the_calltip",
104                                     (expression,), {})
105        else:
106            entity = self.get_entity(expression)
107            return get_arg_text(entity)
108
109    def get_entity(self, expression):
110        """Return the object corresponding to expression evaluated
111        in a namespace spanning sys.modules and __main.dict__.
112        """
113        if expression:
114            namespace = sys.modules.copy()
115            namespace.update(__main__.__dict__)
116            try:
117                return eval(expression, namespace)
118            except BaseException:
119                # An uncaught exception closes idle, and eval can raise any
120                # exception, especially if user classes are involved.
121                return None
122
123def _find_constructor(class_ob):
124    # Given a class object, return a function object used for the
125    # constructor (ie, __init__() ) or None if we can't find one.
126    try:
127        return class_ob.__init__.im_func
128    except AttributeError:
129        for base in class_ob.__bases__:
130            rc = _find_constructor(base)
131            if rc is not None: return rc
132    return None
133
134# The following are used in get_arg_text
135_MAX_COLS = 85
136_MAX_LINES = 5  # enough for bytes
137_INDENT = ' '*4  # for wrapped signatures
138
139def get_arg_text(ob):
140    '''Return a string describing the signature of a callable object, or ''.
141
142    For Python-coded functions and methods, the first line is introspected.
143    Delete 'self' parameter for classes (.__init__) and bound methods.
144    The next lines are the first lines of the doc string up to the first
145    empty line or _MAX_LINES.    For builtins, this typically includes
146    the arguments in addition to the return value.
147    '''
148    argspec = ""
149    try:
150        ob_call = ob.__call__
151    except BaseException:
152        if type(ob) is types.ClassType:  # old-style
153            ob_call = ob
154        else:
155            return argspec
156
157    arg_offset = 0
158    if type(ob) in (types.ClassType, types.TypeType):
159        # Look for the first __init__ in the class chain with .im_func.
160        # Slot wrappers (builtins, classes defined in funcs) do not.
161        fob = _find_constructor(ob)
162        if fob is None:
163            fob = lambda: None
164        else:
165            arg_offset = 1
166    elif type(ob) == types.MethodType:
167        # bit of a hack for methods - turn it into a function
168        # and drop the "self" param for bound methods
169        fob = ob.im_func
170        if ob.im_self is not None:
171            arg_offset = 1
172    elif type(ob_call) == types.MethodType:
173        # a callable class instance
174        fob = ob_call.im_func
175        arg_offset = 1
176    else:
177        fob = ob
178    # Try to build one for Python defined functions
179    if type(fob) in [types.FunctionType, types.LambdaType]:
180        argcount = fob.func_code.co_argcount
181        real_args = fob.func_code.co_varnames[arg_offset:argcount]
182        defaults = fob.func_defaults or []
183        defaults = list(map(lambda name: "=%s" % repr(name), defaults))
184        defaults = [""] * (len(real_args) - len(defaults)) + defaults
185        items = map(lambda arg, dflt: arg + dflt, real_args, defaults)
186        for flag, pre, name in ((0x4, '*', 'args'), (0x8, '**', 'kwargs')):
187            if fob.func_code.co_flags & flag:
188                pre_name = pre + name
189                if name not in real_args:
190                    items.append(pre_name)
191                else:
192                    i = 1
193                    while ((name+'%s') % i) in real_args:
194                        i += 1
195                    items.append((pre_name+'%s') % i)
196        argspec = ", ".join(items)
197        argspec = "(%s)" % re.sub("(?<!\d)\.\d+", "<tuple>", argspec)
198
199    lines = (textwrap.wrap(argspec, _MAX_COLS, subsequent_indent=_INDENT)
200            if len(argspec) > _MAX_COLS else [argspec] if argspec else [])
201
202    if isinstance(ob_call, types.MethodType):
203        doc = ob_call.__doc__
204    else:
205        doc = getattr(ob, "__doc__", "")
206    if doc:
207        for line in doc.split('\n', _MAX_LINES)[:_MAX_LINES]:
208            line = line.strip()
209            if not line:
210                break
211            if len(line) > _MAX_COLS:
212                line = line[: _MAX_COLS - 3] + '...'
213            lines.append(line)
214        argspec = '\n'.join(lines)
215    return argspec
216
217if __name__ == '__main__':
218    from unittest import main
219    main('idlelib.idle_test.test_calltips', verbosity=2)
220