Enabling Code Completion in an embedded Python Interpreter

Question

I have got a PyQT widget interpreter working, the code picked up from here is as follows:

import os
import re
import sys
import code

from PyQt4.QtGui impo         


        

Answer 1

If you want to save yourself some time - take a look at spyderlib, it contains a widget that embeds an interactive Python interpreter with some interaction sugar such as code completion. The bits of specific interest are

• spyderlib/widgets/sourcecode/codeeditor.py
• spyderlib/shell.py
• spyderlib/editor.py
• spyderlib/widgets/externalshell/pythonshell.py
• spyderlib/utiils/module_completion.py
• spyderlib/plugins/externalconsole.py
• spyderlib/plugins/console.py
• spyderlib/plugins/editor.py

The only caveat I have with spyderlib is that you can't just use that doodad on it's own - somewhere I have a version I extracted that contains the bare minimum of support modules needed to run. If you run into the same problem I did regarding the bloat send me a msg and I'll check my stuff into github for you to grab.

I also seem to remember there's an Qt based interactive Python interpreter widget that is used in NumPy or SciPy - I think it originally came from the ipython project however. It's pretty nice because it actually splits the interpeter from the execution of code - so if your code crashes, your interpreter doesn't crash with it. But, in that case you can't modify the Pythonic contents of other threads.. The spyderlib version can work both ways.

Answer 2

I have an open-source PyQt based Python interpreter that you can find here: http://docs.projexsoftware.com/api/projexui/

The specific class is the XConsoleEdit found in projexui.widgets.xconsoleedit. It has auto-completion built-in.

Hope that helps!

Answer 3

I think you are referring to rlcompleter's Completer object.

You can used it like so:

from rlcompleter import Completer

line = str(...)

completer = Completer(self.interpreter.locals)
suggestion = completer.complete(line, 0)
self.insertPlainText(suggestion)

The numeric argument indicates the n-th suggestion, and you can iterate over it until it returns None.

For example, say we have

>>> my_data = '012345'

then

>>> completer.complete('my_', 0)
'my_data'
>>> completer.complete('my_data.s', 0)
'my_data.split('
>>> completer.complete('my_data.s', 1)
'my_data.splitlines('

---

Note that while the code above uses interpreter.locals, you can apply a wider search (but be sure to provide a dictionary).

Answer 4

I get auto complete from rlcompleter2, but there are two problems in the following code,

1. import xxx as yyy auto complete on yyy doesn't work
2. the locals() are not copied into the interactiveinterpreter, I tried to use this code in Autodesk Maya, eg, run x=3 in maya script editor, and then run x in the pyqt interpreter, it says NameError: name 'x' is not defined. if you do not use maya, this error can be reproduced from external python interpreter as well, first define some variable, then launch this ui, the variable is not copied into the interpreter in the ui.

import os
import re
import sys
import code

from PyQt4.QtGui import *
from PyQt4.QtCore import *


class MyInterpreter(QWidget):

    def __init__(self, parent):

        super(MyInterpreter, self).__init__(parent)
        hBox = QHBoxLayout()

        self.setLayout(hBox)
        self.textEdit = PyInterp(self)

        # this is how you pass in locals to the interpreter
        self.textEdit.initInterpreter(locals())

        self.resize(850, 400)
        # self.centerOnScreen()

        hBox.addWidget(self.textEdit)
        hBox.setMargin(0)
        hBox.setSpacing(0)

    def centerOnScreen(self):
        # center the widget on the screen
        resolution = QDesktopWidget().screenGeometry()
        self.move((resolution.width() / 2) - (self.frameSize().width() / 2),
                  (resolution.height() / 2) - (self.frameSize().height() / 2))


class PyInterp(QTextEdit):

    class InteractiveInterpreter(code.InteractiveInterpreter):

        def __init__(self, locals):
            code.InteractiveInterpreter.__init__(self, locals)

        def runIt(self, command):
            code.InteractiveInterpreter.runsource(self, command)

    def __init__(self,  parent):
        super(PyInterp,  self).__init__(parent)

        sys.stdout = self
        sys.stderr = self
        self.refreshMarker = False  # to change back to >>> from ...
        self.multiLine = False  # code spans more than one line
        self.command = ''    # command to be ran
        self.printBanner()              # print sys info
        self.marker()                   # make the >>> or ... marker
        self.history = []    # list of commands entered
        self.historyIndex = -1
        self.interpreterLocals = {}

        # setting the color for bg and text
        # palette = QPalette()
        # palette.setColor(QPalette.Base, QColor(0, 0, 0))
        # palette.setColor(QPalette.Text, QColor(0, 255, 0))
        # self.setPalette(palette)
        self.setFont(QFont('Courier', 10))

        # initilize interpreter with self locals
        self.initInterpreter(locals())

        from rlcompleter2 import Completer
        self.completer = Completer()

    def printBanner(self):
        self.write(sys.version)
        self.write(' on ' + sys.platform + '\n')
        self.write('PyQt4 ' + PYQT_VERSION_STR + '\n')
        # msg = 'Type !hist for a history view and !hist(n) history index recall'
        # self.write(msg + '\n')

    def marker(self):
        if self.multiLine:
            self.insertPlainText('... ')
        else:
            self.insertPlainText('>>> ')

    def initInterpreter(self, interpreterLocals=None):
        if interpreterLocals:
            # when we pass in locals, we don't want it to be named "self"
            # so we rename it with the name of the class that did the passing
            # and reinsert the locals back into the interpreter dictionary
            selfName = interpreterLocals['self'].__class__.__name__
            interpreterLocalVars = interpreterLocals.pop('self')
            self.interpreterLocals[selfName] = interpreterLocalVars
        else:
            self.interpreterLocals = interpreterLocals
        self.interpreter = self.InteractiveInterpreter(self.interpreterLocals)

    def updateInterpreterLocals(self, newLocals):
        className = newLocals.__class__.__name__
        self.interpreterLocals[className] = newLocals

    def write(self, line):
        self.insertPlainText(line)
        self.ensureCursorVisible()

    def clearCurrentBlock(self):
        # block being current row
        length = len(self.document().lastBlock().text()[4:])
        if length == 0:
            return None
        else:
            # should have a better way of doing this but I can't find it
            [self.textCursor().deletePreviousChar() for x in xrange(length)]
        return True

    def recallHistory(self):
        # used when using the arrow keys to scroll through history
        self.clearCurrentBlock()
        if self.historyIndex <> -1:
            self.insertPlainText(self.history[self.historyIndex])
        return True

    def customCommands(self, command):

        if command == '!hist':  # display history
            self.append('')  # move down one line
            # vars that are in the command are prefixed with ____CC and deleted
            # once the command is done so they don't show up in dir()
            backup = self.interpreterLocals.copy()
            history = self.history[:]
            history.reverse()
            for i, x in enumerate(history):
                iSize = len(str(i))
                delta = len(str(len(history))) - iSize
                line = line = ' ' * delta + '%i: %s' % (i, x) + '\n'
                self.write(line)
            self.updateInterpreterLocals(backup)
            self.marker()
            return True

        if re.match('!hist\(\d+\)', command):  # recall command from history
            backup = self.interpreterLocals.copy()
            history = self.history[:]
            history.reverse()
            index = int(command[6:-1])
            self.clearCurrentBlock()
            command = history[index]
            if command[-1] == ':':
                self.multiLine = True
            self.write(command)
            self.updateInterpreterLocals(backup)
            return True

        return False

    def keyPressEvent(self, event):

        if event.key() == Qt.Key_Tab:
            line = str(self.document().lastBlock().text())[4:]
            self.completer.construct(line)

            if len(self.completer.rl_matches) == 1:
                self.clearCurrentBlock()
                self.insertPlainText(self.completer.rl_matches[0])
            else:
                print 'repeat:', self.completer.repeated

                mod = self.completer.repeated % len(self.completer.completions)
                if mod == 0:
                    # print '\n'.join(self.completer.rl_matches)
                    col_print(self.completer.rl_matches)
                else:

                    print ' '
                    print '\n'.join(self.completer.rl_matches)
                    # print self.completer.rl_matches
                self.marker()
                self.insertPlainText(line)

            return

        if event.key() == Qt.Key_Escape:
            # proper exit
            self.interpreter.runIt('exit()')

        if event.key() == Qt.Key_Down:
            if self.historyIndex == len(self.history):
                self.historyIndex -= 1
            try:
                if self.historyIndex > -1:
                    self.historyIndex -= 1
                    self.recallHistory()
                else:
                    self.clearCurrentBlock()
            except:
                pass
            return None

        if event.key() == Qt.Key_Up:
            try:
                if len(self.history) - 1 > self.historyIndex:
                    self.historyIndex += 1
                    self.recallHistory()
                else:
                    self.historyIndex = len(self.history)
            except:
                pass
            return None

        if event.key() == Qt.Key_Home:
            # set cursor to position 4 in current block. 4 because that's where
            # the marker stops
            blockLength = len(self.document().lastBlock().text()[4:])
            lineLength = len(self.document().toPlainText())
            position = lineLength - blockLength
            textCursor = self.textCursor()
            textCursor.setPosition(position)
            self.setTextCursor(textCursor)
            return None

        if event.key() in [Qt.Key_Left, Qt.Key_Backspace]:
            # don't allow deletion of marker
            # if qt version < 4.7, have to use position() - block().position()
            if self.textCursor().positionInBlock() == 4:
                return None

        if event.key() in [Qt.Key_Return, Qt.Key_Enter]:
            # set cursor to end of line to avoid line splitting
            textCursor = self.textCursor()
            position = len(self.document().toPlainText())
            textCursor.setPosition(position)
            self.setTextCursor(textCursor)

            line = str(self.document().lastBlock().text())[4:]  # remove marker
            line.rstrip()
            self.historyIndex = -1

            if self.customCommands(line):
                return None
            else:
                try:
                    line[-1]
                    self.haveLine = True
                    if line[-1] == ':':
                        self.multiLine = True
                    self.history.insert(0, line)
                except:
                    self.haveLine = False

                if self.haveLine and self.multiLine:  # multi line command
                    self.command += line + '\n'  # + command and line
                    self.append('')  # move down one line
                    self.marker()  # handle marker style
                    return None

                if self.haveLine and not self.multiLine:  # one line command
                    self.command = line  # line is the command
                    self.append('')  # move down one line
                    self.interpreter.runIt(self.command)
                    self.command = ''  # clear command
                    self.marker()  # handle marker style
                    return None

                if self.multiLine and not self.haveLine:  # multi line done
                    self.append('')  # move down one line
                    self.interpreter.runIt(self.command)
                    self.command = ''  # clear command
                    self.multiLine = False  # back to single line
                    self.marker()  # handle marker style
                    return None

                if not self.haveLine and not self.multiLine:  # just enter
                    self.append('')
                    self.marker()
                    return None
                return None

        # allow all other key events
        super(PyInterp, self).keyPressEvent(event)

# http://stackoverflow.com/a/30861871/2052889


def col_print(lines, term_width=90, indent=0, pad=2):
    n_lines = len(lines)
    if n_lines == 0:
        return

    col_width = max(len(line) for line in lines)
    n_cols = int((term_width + pad - indent)/(col_width + pad))
    n_cols = min(n_lines, max(1, n_cols))

    col_len = int(n_lines/n_cols) + (0 if n_lines % n_cols == 0 else 1)
    if (n_cols - 1) * col_len >= n_lines:
        n_cols -= 1

    cols = [lines[i*col_len: i*col_len + col_len] for i in range(n_cols)]

    rows = list(zip(*cols))
    rows_missed = zip(*[col[len(rows):] for col in cols[:-1]])
    rows.extend(rows_missed)

    for row in rows:
        print(" "*indent + (" "*pad).join(line.ljust(col_width)
                                          for line in row))


def main():
    app = QApplication(sys.argv)
    win = MyInterpreter(None)
    win.show()
    sys.exit(app.exec_())


if __name__ == "__main__":
    main()

desired effect: https://gfycat.com/DistantScrawnyCivet

current effect: https://gfycat.com/DeafeningHeavyBoto