[Idle-dev] Patch: clearing breakpoints in IDLE

[Edward K. Ream]

Hi all:

This was originally posted to the main python mailing list.
Please email me if you have comments: I am not a member of idle-dev.


The following patch that lets the user of IDLE clear breakpoints in
exactly the same way that they are set, that is, by right-clicking a
source line containing a breakpoint.

(I've inserted backslashes so this doesn't get line-breaked to death.)

1. In PyShell.py, add the following two lines, indicated by # EKR:

    def __init__(self, *args):
        apply(EditorWindow.__init__, (self,) + args)
        self.text.bind("<<set-breakpoint-here>>",\
            self.set_breakpoint_here)
        self.text.bind("<<clear-this-breakpoint>>",\
            self.clear_this_breakpoint) # EKR
        self.text.bind("<<open-python-shell>>", self.flist.open_shell)

    rmenu_specs = [
        ("Set breakpoint here", "<<set-breakpoint-here>>"),
        ("Clear this breakpoint", "<<clear-this-breakpoint>>"), # EKR
    ]

2. In PyShell.py, add the following new method:

    def clear_this_breakpoint(self, event=None):
        if not self.flist.pyshell or \
            not self.flist.pyshell.interp.debugger:
            self.text.bell()
            return
        self.flist.pyshell.interp.debugger.clear_this_breakpoint(self)

3. In Debugger.py, add the following new method:

    def clear_this_breakpoint(self, edit):
        text = edit.text
        filename = edit.io.filename
        if not filename:
            text.bell()
            return
        lineno = int(float(text.index("insert")))
        msg = self.clear_break(filename, lineno)
        if msg:
            text.bell()
            return
        text.tag_remove("BREAK", "insert linestart", \
            "insert lineend+1char")

I believe that's all there is to it.

Aside 1: Unlike the set_breakpoint_here routine, the call to
self.clear_break in clear_this_breakpoint calls the method of the super
class, i.e., the Bcb class.  I don't understand why Debugger.py bothers
to create a set_break method.  Indeed this comment is strange:

# A literal copy of Bdb.set_break() without the print statement at the
end

There is no print statement in Bdb.set_break in v2.1.

Aside 2: In PyShell.py, it seems silly just to ring a bell in
set_breakpoint_here if the debugger hasn't been opened by the user.  How
about opening it for her?  Like this:

    def set_breakpoint_here(self, event=None):
        if not self.flist.pyshell or \
            not self.flist.pyshell.interp.debugger:
            if 1: # EKR: Try to open debugger automatically.
                self.flist.pyshell.toggle_debugger()
                if not self.flist.pyshell or \
                    not self.flist.pyshell.interp.debugger:
                    self.text.bell()
                    return
            else: # old way
                self.text.bell()
        self.flist.pyshell.interp.debugger.set_breakpoint_here(self)

This seems to work for me.

Edward
--------------------------------------------------------------------
Edward K. Ream   email:  edream@tds.net
Leo: Literate Editor with Outlines
Leo: http://personalpages.tds.net/~edream/front.html
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