240 lines
10 KiB
Python
240 lines
10 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 maxlines
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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, X, 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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CONFIGUPDATEINTERVAL = 1000 # millisec
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def get_spaces_firstword(codeline, c=re.compile(r"^(\s*)(\w*)")):
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"Extract the beginning whitespace and first word from codeline."
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return c.match(codeline).groups()
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def get_line_info(codeline):
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"""Return tuple of (line indent value, codeline, block start keyword).
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The indentation of empty lines (or comment lines) is INFINITY.
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If the line does not start a block, the keyword value is False.
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"""
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spaces, firstword = get_spaces_firstword(codeline)
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indent = len(spaces)
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if len(codeline) == indent or codeline[indent] == '#':
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indent = INFINITY
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opener = firstword in BLOCKOPENERS and firstword
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return indent, codeline, opener
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class CodeContext:
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"Display block context above the edit window."
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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.context 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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self.info[0] is initialized with 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.contextcolors = CodeContext.colors
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self.context = 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(CONFIGUPDATEINTERVAL, self.config_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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"maxlines", type="int", default=15)
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cls.colors = idleConf.GetHighlight(idleConf.CurrentTheme(), 'context')
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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.context 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.context:
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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 horizontal padding and border width.
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padx = 0
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border = 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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border += widget.tk.getint(widget.cget('border'))
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self.context = tkinter.Text(
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self.editwin.top, font=self.textfont,
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bg=self.contextcolors['background'],
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fg=self.contextcolors['foreground'],
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height=1,
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width=1, # Don't request more than we get.
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padx=padx, border=border, relief=SUNKEN, state='disabled')
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self.context.bind('<ButtonRelease-1>', self.jumptoline)
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# Pack the context 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.context.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.context.destroy()
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self.context = None
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return "break"
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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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codeline = self.text.get(f'{linenum}.0', f'{linenum}.end')
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indent, text, opener = get_line_info(codeline)
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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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# 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 context area will be updated with the code,
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up to the number of maxlines.
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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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# Last context_depth context lines.
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context_strings = [x[2] for x in self.info[-self.context_depth:]]
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showfirst = 0 if context_strings[0] else 1
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# Update widget.
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self.context['height'] = len(context_strings) - showfirst
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self.context['state'] = 'normal'
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self.context.delete('1.0', 'end')
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self.context.insert('end', '\n'.join(context_strings[showfirst:]))
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self.context['state'] = 'disabled'
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def jumptoline(self, event=None):
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"Show clicked context line at top of editor."
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lines = len(self.info)
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if lines == 1: # No context lines are showing.
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newtop = 1
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else:
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# Line number clicked.
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contextline = int(float(self.context.index('insert')))
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# Lines not displayed due to maxlines.
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offset = max(1, lines - self.context_depth) - 1
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newtop = self.info[offset + contextline][0]
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self.text.yview(f'{newtop}.0')
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self.update_code_context()
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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.context:
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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 config_timer_event(self):
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"Event on editor text widget triggered every CONFIGUPDATEINTERVAL ms."
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newtextfont = self.text["font"]
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if (self.context and (newtextfont != self.textfont or
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CodeContext.colors != self.contextcolors)):
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self.textfont = newtextfont
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self.contextcolors = CodeContext.colors
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self.context["font"] = self.textfont
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self.context['background'] = self.contextcolors['background']
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self.context['foreground'] = self.contextcolors['foreground']
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self.t2 = self.text.after(CONFIGUPDATEINTERVAL, self.config_timer_event)
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CodeContext.reload()
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if __name__ == "__main__":
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from unittest import main
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main('idlelib.idle_test.test_codecontext', verbosity=2, exit=False)
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# Add htest.
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