mirror of https://github.com/python/cpython
140 lines
6.0 KiB
Python
140 lines
6.0 KiB
Python
"""CodeContext - Display the block context of code at top of edit window
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Once code has scolled off the top of the screen, it can be difficult
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to determine which block you are in. This extension implements a pane
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at the top of each IDLE edit window which provides block structure
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hints. These hints are the lines which contain the block opening
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keywords, e.g. 'if', for the enclosing block. The number of hint lines
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is determined by the numlines variable in the CodeContext section of
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config-extensions.def. Lines which do not open blocks are not shown in
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the context hints pane.
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"""
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import Tkinter
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from configHandler import idleConf
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from PyShell import PyShell
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import re
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BLOCKOPENERS = dict([(x, None) for x in ("class", "def", "elif", "else",
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"except", "finally", "for", "if",
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"try", "while")])
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INFINITY = 1 << 30
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UPDATEINTERVAL = 100 # millisec
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FONTUPDATEINTERVAL = 1000 # millisec
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getspacesfirstword = lambda s, c=re.compile(r"^(\s*)(\w*)"): c.match(s).groups()
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class CodeContext:
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menudefs = [('options', [('!Code Conte_xt', '<<toggle-code-context>>')])]
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numlines = idleConf.GetOption("extensions", "CodeContext",
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"numlines", type="int", default=3)
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bgcolor = idleConf.GetOption("extensions", "CodeContext",
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"bgcolor", type="str", default="LightGray")
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fgcolor = idleConf.GetOption("extensions", "CodeContext",
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"fgcolor", type="str", default="Black")
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default_on = idleConf.GetOption("extensions", "CodeContext",
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"default_on", type="int", default=0)
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def __init__(self, editwin):
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if isinstance(editwin, PyShell):
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return
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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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# Dummy line, which starts the "block" of the whole document:
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self.info = list(self.interesting_lines(1))
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self.lastfirstline = 1
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if self.default_on:
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self.toggle_code_context_event()
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self.editwin.setvar('<<toggle-code-context>>', True)
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# Start two update cycles, one for context lines, one for font changes.
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self.text.after(UPDATEINTERVAL, self.timer_event)
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self.text.after(FONTUPDATEINTERVAL, self.font_timer_event)
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def toggle_code_context_event(self, event=None):
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if not self.label:
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self.label = Tkinter.Label(self.editwin.top,
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text="\n" * (self.numlines - 1),
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anchor="w", justify="left",
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font=self.textfont,
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bg=self.bgcolor, fg=self.fgcolor,
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relief="sunken",
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width=1, # Don't request more than we get
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)
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self.label.pack(side="top", fill="x", expand=0,
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after=self.editwin.status_bar)
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else:
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self.label.destroy()
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self.label = None
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def get_line_info(self, linenum):
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"""Get the line indent value, text, and any 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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There is a dummy block start, with indentation -1 and text "".
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Return the indent level, text (including leading whitespace),
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and the block opening keyword.
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"""
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if linenum == 0:
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return -1, "", True
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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 interesting_lines(self, firstline):
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"""Generator which yields context lines, starting at firstline."""
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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 line_index in xrange(firstline, -1, -1):
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indent, text, opener = self.get_line_info(line_index)
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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 line_index < firstline:
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yield line_index, text
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def update_label(self):
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firstline = int(self.text.index("@0,0").split('.')[0])
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if self.lastfirstline == firstline:
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return
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self.lastfirstline = firstline
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tmpstack = []
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for line_index, text in self.interesting_lines(firstline):
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# Remove irrelevant self.info items, and when we reach a relevant
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# item (which must happen because of the dummy element), break.
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while self.info[-1][0] > line_index:
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del self.info[-1]
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if self.info[-1][0] == line_index:
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break
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tmpstack.append((line_index, text))
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while tmpstack:
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self.info.append(tmpstack.pop())
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lines = [""] * max(0, self.numlines - len(self.info)) + \
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[x[1] for x in self.info[-self.numlines:]]
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self.label["text"] = '\n'.join(lines)
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def timer_event(self):
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if self.label:
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self.update_label()
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self.text.after(UPDATEINTERVAL, self.timer_event)
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def font_timer_event(self):
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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.text.after(FONTUPDATEINTERVAL, self.font_timer_event)
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