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Diffstat (limited to 'Lib/idlelib/codecontext.py')
| -rw-r--r-- | Lib/idlelib/codecontext.py | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/Lib/idlelib/codecontext.py b/Lib/idlelib/codecontext.py new file mode 100644 index 0000000000..f25e1b33a0 --- /dev/null +++ b/Lib/idlelib/codecontext.py @@ -0,0 +1,178 @@ +"""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 re +from sys import maxsize as INFINITY + +import tkinter +from tkinter.constants import TOP, LEFT, X, W, SUNKEN + +from idlelib.config import idleConf + +BLOCKOPENERS = {"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: + # Calculate the border width and horizontal padding required to + # align the context with the text in the main Text widget. + # + # All values are passed through getint(), since some + # values may be pixel objects, which can't simply be added to ints. + widgets = self.editwin.text, self.editwin.text_frame + # Calculate the required vertical padding + padx = 0 + for widget in widgets: + padx += widget.tk.getint(widget.pack_info()['padx']) + padx += widget.tk.getint(widget.cget('padx')) + # Calculate the required border width + border = 0 + for widget in widgets: + border += widget.tk.getint(widget.cget('border')) + self.label = tkinter.Label(self.editwin.top, + text="\n" * (self.context_depth - 1), + anchor=W, justify=LEFT, + font=self.textfont, + bg=self.bgcolor, fg=self.fgcolor, + width=1, #don't request more than we get + padx=padx, border=border, + relief=SUNKEN) + # Pack the label widget before and above the text_frame widget, + # thus ensuring that it will appear directly above text_frame + self.label.pack(side=TOP, fill=X, expand=False, + before=self.editwin.text_frame) + else: + self.label.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 range(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) |