How to get text next to cursor in QTextEdit in PyQt4

Question

I am making a light IDE for bash scripts, and i want an option, when i press Ctrl + / >> one line, where my 'textCursor' is, will be commented, and i have managed to do that, but i also want to uncomment line with the same command. But i cannot get text next to 'textCursor'.

def commentShortcut(self):
    cursor = self.textCursor()
    Y = cursor.blockNumber()
    self.moveCursor(QtGui.QTextCursor.End)
    cursor = QtGui.QTextCursor(self.document().findBlockByLineNumber(Y))
    self.setTextCursor(cursor)
    self.insertPlainText("#")

This part of the code moves my textCursor to the start of that line where I insert '#' (comment sign) with self.insertPlainText() function.

note: class is inheriting QTextEdit and that's why i am using it only with self.

To sum up, i just need an method to check character next to textCursor and if that character is '#' i will remove it, and if it is not, then i will insert new '#' any help would be appretiated.

Answer 1

You must move to the beginning of the line, then skip the blank spaces, select the first character and compare it, then for the removal process you must remove the "#" and the blank spaces to the right, and for the insertion it is recommended to insert "# "

Ps: I could not try the Shortcut Ctrl + / for what I use: Ctrl + R

import sys
from PyQt4 import QtCore, QtGui

class TextEdit(QtGui.QTextEdit):
    def __init__(self, *args, **kwargs):
        QtGui.QWidget.__init__(self, *args, **kwargs)
        shortcut = QtGui.QShortcut(QtGui.QKeySequence("Ctrl+R"), self)
        shortcut.activated.connect(self.commentShortcut)

    def commentShortcut(self):
        pos = self.textCursor().position()
        self.moveCursor(QtGui.QTextCursor.StartOfLine)
        line_text = self.textCursor().block().text()
        if self.textCursor().block().text().startswith(" "):
            # skip the white space
            self.moveCursor(QtGui.QTextCursor.NextWord)
        self.moveCursor(QtGui.QTextCursor.NextCharacter,QtGui.QTextCursor.KeepAnchor)
        character = self.textCursor().selectedText()
        if character == "#":
            # delete #
            self.textCursor().deletePreviousChar()
            # delete white space 
            self.moveCursor(QtGui.QTextCursor.NextWord,QtGui.QTextCursor.KeepAnchor)
            self.textCursor().removeSelectedText()
        else:
            self.moveCursor(QtGui.QTextCursor.PreviousCharacter,QtGui.QTextCursor.KeepAnchor)
            self.textCursor().insertText("# ")
        cursor = QtGui.QTextCursor(self.textCursor())
        cursor.setPosition(pos)
        self.setTextCursor(cursor)


if __name__ == '__main__':
    app = QtGui.QApplication(sys.argv)
    w = TextEdit()
    w.append('''

#!/bin/bash
# Simple line count example, using bash
#
# Bash tutorial: http://linuxconfig.org/Bash_scripting_Tutorial#8-2-read-file-into-bash-array
# My scripting link: http://www.macs.hw.ac.uk/~hwloidl/docs/index.html#scripting
#
# Usage: ./line_count.sh file
# -----------------------------------------------------------------------------

# Link filedescriptor 10 with stdin
exec 10<&0
# stdin replaced with a file supplied as a first argument
exec < $1
# remember the name of the input file
in=$1

# init
file="current_line.txt"
let count=0

# this while loop iterates over all lines of the file
while read LINE
do
    # increase line counter 
    ((count++))
    # write current line to a tmp file with name $file (not needed for counting)
    echo $LINE > $file
    # this checks the return code of echo (not needed for writing; just for demo)
    if [ $? -ne 0 ] 
     then echo "Error in writing to file ${file}; check its permissions!"
    fi
done

echo "Number of lines: $count"
echo "The last line of the file is: `cat ${file}`"

# Note: You can achieve the same by just using the tool wc like this
echo "Expected number of lines: `wc -l $in`"

# restore stdin from filedescriptor 10
# and close filedescriptor 10
exec 0<&10 10<&-
        ''')
    w.show()
    sys.exit(app.exec_())