Test calltips in scintilla with Python

call_tip.py

# CallTips Python Scintilla

import sys

from PyQt4.QtGui import *
from PyQt4.Qsci import QsciScintilla, QsciLexerPython

CALLTIPS = True


class Lexer(QsciLexerPython):

    def __init__(self, p):
        super(Lexer, self).__init__(p)


class Editor(QsciScintilla):

    def __init__(self):
        super(Editor, self).__init__()
        self.setAutoIndent(True)
        lex = Lexer(self)
        self.setLexer(lex)
        self._calltip = False
        if CALLTIPS:
            self._calltip = CallTip(self)

    def keyPressEvent(self, event):
        super(Editor, self).keyPressEvent(event)
        if event.text() == '(' and self._calltip:
            self._calltip.showtip()
        elif event.text() == ')' and self._calltip:
            self._calltip.close()


class CallTip:

    def __init__(self, editor):
        self._editor = editor

    def close(self):
        self._editor.SendScintilla(QsciScintilla.SCI_CALLTIPCANCEL)

    def showtip(self):
        expression = self.__get_expression()
        if not expression:
            return

        if expression.find('(') != -1:
            return

        argspec = self.__get_argspec(expression)
        if not argspec:
            return
        pos = self._editor.SendScintilla(QsciScintilla.SCI_GETCURRENTPOS)
        self._editor.SendScintilla(QsciScintilla.SCI_CALLTIPSHOW,
                                   pos, argspec.encode())

    def __get_expression(self):
        line, index = self._editor.getCursorPosition()
        exp = self._editor.text(line)[:index].split()[-1][:-1]
        return exp

    def __get_argspec(self, exp):
        obj = self.__get_entity(exp)
        string_signature = ""
        try:
            obj.__call__
        except AttributeError:
            return string_signature

        doc = obj.__doc__
        if doc:
            lines = []
            for line in doc.splitlines():
                line = line.strip()
                if not line:
                    break
                lines.append(line)
            string_signature = '\n'.join(lines)
        return string_signature

    def __get_entity(self, exp):
        if exp:
            namespace = sys.modules.copy()
            try:
                return eval(exp, namespace)
            except Exception:
                return None

if __name__ == "__main__":

    app = QApplication([])
    w = Editor()
    w.show()
    w.resize(700, 500)
    sys.exit(app.exec_())