python-2.5.2/win32/Lib/idlelib/CodeContext.py
changeset 0 ae805ac0140d
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python-2.5.2/win32/Lib/idlelib/CodeContext.py	Fri Apr 03 17:19:34 2009 +0100
@@ -0,0 +1,167 @@
+"""CodeContext - Extension to display the block context above the edit window
+
+Once code has scrolled off the top of a window, it can be difficult to
+determine which block you are in.  This extension implements a pane at the top
+of each IDLE edit window which provides block structure hints.  These hints are
+the lines which contain the block opening keywords, e.g. 'if', for the
+enclosing block.  The number of hint lines is determined by the numlines
+variable in the CodeContext section of config-extensions.def. Lines which do
+not open blocks are not shown in the context hints pane.
+
+"""
+import Tkinter
+from configHandler import idleConf
+import re
+from sys import maxint as INFINITY
+
+BLOCKOPENERS = set(["class", "def", "elif", "else", "except", "finally", "for",
+                    "if", "try", "while", "with"])
+UPDATEINTERVAL = 100 # millisec
+FONTUPDATEINTERVAL = 1000 # millisec
+
+getspacesfirstword =\
+                   lambda s, c=re.compile(r"^(\s*)(\w*)"): c.match(s).groups()
+
+class CodeContext:
+    menudefs = [('options', [('!Code Conte_xt', '<<toggle-code-context>>')])]
+
+    context_depth = idleConf.GetOption("extensions", "CodeContext",
+                                       "numlines", type="int", default=3)
+    bgcolor = idleConf.GetOption("extensions", "CodeContext",
+                                 "bgcolor", type="str", default="LightGray")
+    fgcolor = idleConf.GetOption("extensions", "CodeContext",
+                                 "fgcolor", type="str", default="Black")
+    def __init__(self, editwin):
+        self.editwin = editwin
+        self.text = editwin.text
+        self.textfont = self.text["font"]
+        self.label = None
+        # self.info is a list of (line number, indent level, line text, block
+        # keyword) tuples providing the block structure associated with
+        # self.topvisible (the linenumber of the line displayed at the top of
+        # the edit window). self.info[0] is initialized as a 'dummy' line which
+        # starts the toplevel 'block' of the module.
+        self.info = [(0, -1, "", False)]
+        self.topvisible = 1
+        visible = idleConf.GetOption("extensions", "CodeContext",
+                                     "visible", type="bool", default=False)
+        if visible:
+            self.toggle_code_context_event()
+            self.editwin.setvar('<<toggle-code-context>>', True)
+        # Start two update cycles, one for context lines, one for font changes.
+        self.text.after(UPDATEINTERVAL, self.timer_event)
+        self.text.after(FONTUPDATEINTERVAL, self.font_timer_event)
+
+    def toggle_code_context_event(self, event=None):
+        if not self.label:
+            self.pad_frame = Tkinter.Frame(self.editwin.top,
+                                           bg=self.bgcolor, border=2,
+                                           relief="sunken")
+            self.label = Tkinter.Label(self.pad_frame,
+                                      text="\n" * (self.context_depth - 1),
+                                      anchor="w", justify="left",
+                                      font=self.textfont,
+                                      bg=self.bgcolor, fg=self.fgcolor,
+                                      border=0,
+                                      width=1, # Don't request more than we get
+                                      )
+            self.label.pack(side="top", fill="x", expand=True,
+                            padx=4, pady=0)
+            self.pad_frame.pack(side="top", fill="x", expand=False,
+                                padx=0, pady=0,
+                                after=self.editwin.status_bar)
+        else:
+            self.label.destroy()
+            self.pad_frame.destroy()
+            self.label = None
+        idleConf.SetOption("extensions", "CodeContext", "visible",
+                           str(self.label is not None))
+        idleConf.SaveUserCfgFiles()
+
+    def get_line_info(self, linenum):
+        """Get the line indent value, text, and any block start keyword
+
+        If the line does not start a block, the keyword value is False.
+        The indentation of empty lines (or comment lines) is INFINITY.
+
+        """
+        text = self.text.get("%d.0" % linenum, "%d.end" % linenum)
+        spaces, firstword = getspacesfirstword(text)
+        opener = firstword in BLOCKOPENERS and firstword
+        if len(text) == len(spaces) or text[len(spaces)] == '#':
+            indent = INFINITY
+        else:
+            indent = len(spaces)
+        return indent, text, opener
+
+    def get_context(self, new_topvisible, stopline=1, stopindent=0):
+        """Get context lines, starting at new_topvisible and working backwards.
+
+        Stop when stopline or stopindent is reached. Return a tuple of context
+        data and the indent level at the top of the region inspected.
+
+        """
+        assert stopline > 0
+        lines = []
+        # The indentation level we are currently in:
+        lastindent = INFINITY
+        # For a line to be interesting, it must begin with a block opening
+        # keyword, and have less indentation than lastindent.
+        for linenum in xrange(new_topvisible, stopline-1, -1):
+            indent, text, opener = self.get_line_info(linenum)
+            if indent < lastindent:
+                lastindent = indent
+                if opener in ("else", "elif"):
+                    # We also show the if statement
+                    lastindent += 1
+                if opener and linenum < new_topvisible and indent >= stopindent:
+                    lines.append((linenum, indent, text, opener))
+                if lastindent <= stopindent:
+                    break
+        lines.reverse()
+        return lines, lastindent
+
+    def update_code_context(self):
+        """Update context information and lines visible in the context pane.
+
+        """
+        new_topvisible = int(self.text.index("@0,0").split('.')[0])
+        if self.topvisible == new_topvisible:      # haven't scrolled
+            return
+        if self.topvisible < new_topvisible:       # scroll down
+            lines, lastindent = self.get_context(new_topvisible,
+                                                 self.topvisible)
+            # retain only context info applicable to the region
+            # between topvisible and new_topvisible:
+            while self.info[-1][1] >= lastindent:
+                del self.info[-1]
+        elif self.topvisible > new_topvisible:     # scroll up
+            stopindent = self.info[-1][1] + 1
+            # retain only context info associated
+            # with lines above new_topvisible:
+            while self.info[-1][0] >= new_topvisible:
+                stopindent = self.info[-1][1]
+                del self.info[-1]
+            lines, lastindent = self.get_context(new_topvisible,
+                                                 self.info[-1][0]+1,
+                                                 stopindent)
+        self.info.extend(lines)
+        self.topvisible = new_topvisible
+
+        # empty lines in context pane:
+        context_strings = [""] * max(0, self.context_depth - len(self.info))
+        # followed by the context hint lines:
+        context_strings += [x[2] for x in self.info[-self.context_depth:]]
+        self.label["text"] = '\n'.join(context_strings)
+
+    def timer_event(self):
+        if self.label:
+            self.update_code_context()
+        self.text.after(UPDATEINTERVAL, self.timer_event)
+
+    def font_timer_event(self):
+        newtextfont = self.text["font"]
+        if self.label and newtextfont != self.textfont:
+            self.textfont = newtextfont
+            self.label["font"] = self.textfont
+        self.text.after(FONTUPDATEINTERVAL, self.font_timer_event)