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222 lines
9.5 KiB
Python
222 lines
9.5 KiB
Python
"""codecontext - display the block context above the edit window
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Once code has scrolled off the top of a window, it can be difficult to
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determine which block you are in. This extension implements a pane at the top
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of each IDLE edit window which provides block structure hints. These hints are
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the lines which contain the block opening keywords, e.g. 'if', for the
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enclosing block. The number of hint lines is determined by the numlines
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variable in the codecontext section of config-extensions.def. Lines which do
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not open blocks are not shown in the context hints pane.
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"""
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import re
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from sys import maxsize as INFINITY
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import tkinter
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from tkinter.constants import TOP, LEFT, X, W, SUNKEN
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from idlelib.config import idleConf
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BLOCKOPENERS = {"class", "def", "elif", "else", "except", "finally", "for",
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"if", "try", "while", "with", "async"}
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UPDATEINTERVAL = 100 # millisec
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FONTUPDATEINTERVAL = 1000 # millisec
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def getspacesfirstword(s, c=re.compile(r"^(\s*)(\w*)")):
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"Extract the beginning whitespace and first word from s."
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return c.match(s).groups()
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class CodeContext:
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"Display block context above the edit window."
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bgcolor = "LightGray"
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fgcolor = "Black"
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def __init__(self, editwin):
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"""Initialize settings for context block.
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editwin is the Editor window for the context block.
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self.text is the editor window text widget.
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self.textfont is the editor window font.
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self.label displays the code context text above the editor text.
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Initially None it is toggled via <<toggle-code-context>>.
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self.topvisible is the number of the top text line displayed.
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self.info is a list of (line number, indent level, line text,
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block keyword) tuples for the block structure above topvisible.
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s self.info[0] is initialized a 'dummy' line which
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# starts the toplevel 'block' of the module.
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self.t1 and self.t2 are two timer events on the editor text widget to
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monitor for changes to the context text or editor font.
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"""
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self.editwin = editwin
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self.text = editwin.text
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self.textfont = self.text["font"]
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self.label = None
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self.topvisible = 1
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self.info = [(0, -1, "", False)]
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# Start two update cycles, one for context lines, one for font changes.
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self.t1 = self.text.after(UPDATEINTERVAL, self.timer_event)
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self.t2 = self.text.after(FONTUPDATEINTERVAL, self.font_timer_event)
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@classmethod
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def reload(cls):
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"Load class variables from config."
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cls.context_depth = idleConf.GetOption("extensions", "CodeContext",
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"numlines", type="int", default=3)
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## cls.bgcolor = idleConf.GetOption("extensions", "CodeContext",
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## "bgcolor", type="str", default="LightGray")
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## cls.fgcolor = idleConf.GetOption("extensions", "CodeContext",
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## "fgcolor", type="str", default="Black")
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def __del__(self):
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"Cancel scheduled events."
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try:
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self.text.after_cancel(self.t1)
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self.text.after_cancel(self.t2)
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except:
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pass
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def toggle_code_context_event(self, event=None):
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"""Toggle code context display.
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If self.label doesn't exist, create it to match the size of the editor
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window text (toggle on). If it does exist, destroy it (toggle off).
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Return 'break' to complete the processing of the binding.
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"""
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if not self.label:
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# Calculate the border width and horizontal padding required to
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# align the context with the text in the main Text widget.
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#
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# All values are passed through getint(), since some
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# values may be pixel objects, which can't simply be added to ints.
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widgets = self.editwin.text, self.editwin.text_frame
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# Calculate the required vertical padding
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padx = 0
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for widget in widgets:
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padx += widget.tk.getint(widget.pack_info()['padx'])
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padx += widget.tk.getint(widget.cget('padx'))
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# Calculate the required border width
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border = 0
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for widget in widgets:
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border += widget.tk.getint(widget.cget('border'))
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self.label = tkinter.Label(
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self.editwin.top, text="\n" * (self.context_depth - 1),
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anchor=W, justify=LEFT, font=self.textfont,
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bg=self.bgcolor, fg=self.fgcolor,
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width=1, #don't request more than we get
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padx=padx, border=border, relief=SUNKEN)
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# Pack the label widget before and above the text_frame widget,
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# thus ensuring that it will appear directly above text_frame
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self.label.pack(side=TOP, fill=X, expand=False,
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before=self.editwin.text_frame)
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else:
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self.label.destroy()
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self.label = None
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return "break"
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def get_line_info(self, linenum):
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"""Return tuple of (line indent value, text, and block start keyword).
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If the line does not start a block, the keyword value is False.
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The indentation of empty lines (or comment lines) is INFINITY.
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"""
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text = self.text.get("%d.0" % linenum, "%d.end" % linenum)
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spaces, firstword = getspacesfirstword(text)
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opener = firstword in BLOCKOPENERS and firstword
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if len(text) == len(spaces) or text[len(spaces)] == '#':
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indent = INFINITY
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else:
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indent = len(spaces)
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return indent, text, opener
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def get_context(self, new_topvisible, stopline=1, stopindent=0):
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"""Return a list of block line tuples and the 'last' indent.
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The tuple fields are (linenum, indent, text, opener).
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The list represents header lines from new_topvisible back to
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stopline with successively shorter indents > stopindent.
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The list is returned ordered by line number.
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Last indent returned is the smallest indent observed.
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"""
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assert stopline > 0
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lines = []
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# The indentation level we are currently in:
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lastindent = INFINITY
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# For a line to be interesting, it must begin with a block opening
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# keyword, and have less indentation than lastindent.
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for linenum in range(new_topvisible, stopline-1, -1):
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indent, text, opener = self.get_line_info(linenum)
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if indent < lastindent:
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lastindent = indent
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if opener in ("else", "elif"):
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# We also show the if statement
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lastindent += 1
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if opener and linenum < new_topvisible and indent >= stopindent:
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lines.append((linenum, indent, text, opener))
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if lastindent <= stopindent:
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break
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lines.reverse()
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return lines, lastindent
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def update_code_context(self):
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"""Update context information and lines visible in the context pane.
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No update is done if the text hasn't been scrolled. If the text
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was scrolled, the lines that should be shown in the context will
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be retrieved and the label widget will be updated with the code,
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padded with blank lines so that the code appears on the bottom of
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the context label.
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"""
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new_topvisible = int(self.text.index("@0,0").split('.')[0])
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if self.topvisible == new_topvisible: # haven't scrolled
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return
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if self.topvisible < new_topvisible: # scroll down
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lines, lastindent = self.get_context(new_topvisible,
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self.topvisible)
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# retain only context info applicable to the region
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# between topvisible and new_topvisible:
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while self.info[-1][1] >= lastindent:
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del self.info[-1]
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else: # self.topvisible > new_topvisible: # scroll up
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stopindent = self.info[-1][1] + 1
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# retain only context info associated
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# with lines above new_topvisible:
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while self.info[-1][0] >= new_topvisible:
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stopindent = self.info[-1][1]
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del self.info[-1]
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lines, lastindent = self.get_context(new_topvisible,
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self.info[-1][0]+1,
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stopindent)
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self.info.extend(lines)
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self.topvisible = new_topvisible
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# empty lines in context pane:
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context_strings = [""] * max(0, self.context_depth - len(self.info))
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# followed by the context hint lines:
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context_strings += [x[2] for x in self.info[-self.context_depth:]]
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self.label["text"] = '\n'.join(context_strings)
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def timer_event(self):
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"Event on editor text widget triggered every UPDATEINTERVAL ms."
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if self.label:
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self.update_code_context()
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self.t1 = self.text.after(UPDATEINTERVAL, self.timer_event)
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def font_timer_event(self):
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"Event on editor text widget triggered every FONTUPDATEINTERVAL ms."
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newtextfont = self.text["font"]
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if self.label and newtextfont != self.textfont:
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self.textfont = newtextfont
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self.label["font"] = self.textfont
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self.t2 = self.text.after(FONTUPDATEINTERVAL, self.font_timer_event)
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CodeContext.reload()
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if __name__ == "__main__": # pragma: no cover
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import unittest
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unittest.main('idlelib.idle_test.test_codecontext', verbosity=2, exit=False)
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