cpython/Lib/idlelib/searchengine.py

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'''Define SearchEngine for search dialogs.'''
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import re
from tkinter import StringVar, BooleanVar, TclError
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import tkinter.messagebox as tkMessageBox
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def get(root):
'''Return the singleton SearchEngine instance for the process.
The single SearchEngine saves settings between dialog instances.
If there is not a SearchEngine already, make one.
'''
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if not hasattr(root, "_searchengine"):
root._searchengine = SearchEngine(root)
# This creates a cycle that persists until root is deleted.
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return root._searchengine
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class SearchEngine:
"""Handles searching a text widget for Find, Replace, and Grep."""
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def __init__(self, root):
'''Initialize Variables that save search state.
The dialogs bind these to the UI elements present in the dialogs.
'''
self.root = root # need for report_error()
self.patvar = StringVar(root, '') # search pattern
self.revar = BooleanVar(root, False) # regular expression?
self.casevar = BooleanVar(root, False) # match case?
self.wordvar = BooleanVar(root, False) # match whole word?
self.wrapvar = BooleanVar(root, True) # wrap around buffer?
self.backvar = BooleanVar(root, False) # search backwards?
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# Access methods
def getpat(self):
return self.patvar.get()
def setpat(self, pat):
self.patvar.set(pat)
def isre(self):
return self.revar.get()
def iscase(self):
return self.casevar.get()
def isword(self):
return self.wordvar.get()
def iswrap(self):
return self.wrapvar.get()
def isback(self):
return self.backvar.get()
# Higher level access methods
def setcookedpat(self, pat):
"Set pattern after escaping if re."
# called only in search.py: 66
if self.isre():
pat = re.escape(pat)
self.setpat(pat)
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def getcookedpat(self):
pat = self.getpat()
if not self.isre(): # if True, see setcookedpat
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pat = re.escape(pat)
if self.isword():
pat = r"\b%s\b" % pat
return pat
def getprog(self):
"Return compiled cooked search pattern."
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pat = self.getpat()
if not pat:
self.report_error(pat, "Empty regular expression")
return None
pat = self.getcookedpat()
flags = 0
if not self.iscase():
flags = flags | re.IGNORECASE
try:
prog = re.compile(pat, flags)
except re.error as what:
args = what.args
msg = args[0]
col = args[1] if len(args) >= 2 else -1
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self.report_error(pat, msg, col)
return None
return prog
def report_error(self, pat, msg, col=-1):
# Derived class could override this with something fancier
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msg = "Error: " + str(msg)
if pat:
msg = msg + "\nPattern: " + str(pat)
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if col >= 0:
msg = msg + "\nOffset: " + str(col)
tkMessageBox.showerror("Regular expression error",
msg, master=self.root)
def search_text(self, text, prog=None, ok=0):
'''Return (lineno, matchobj) or None for forward/backward search.
This function calls the right function with the right arguments.
It directly return the result of that call.
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Text is a text widget. Prog is a precompiled pattern.
The ok parameter is a bit complicated as it has two effects.
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If there is a selection, the search begin at either end,
depending on the direction setting and ok, with ok meaning that
the search starts with the selection. Otherwise, search begins
at the insert mark.
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To aid progress, the search functions do not return an empty
match at the starting position unless ok is True.
'''
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if not prog:
prog = self.getprog()
if not prog:
return None # Compilation failed -- stop
wrap = self.wrapvar.get()
first, last = get_selection(text)
if self.isback():
if ok:
start = last
else:
start = first
line, col = get_line_col(start)
res = self.search_backward(text, prog, line, col, wrap, ok)
else:
if ok:
start = first
else:
start = last
line, col = get_line_col(start)
res = self.search_forward(text, prog, line, col, wrap, ok)
return res
def search_forward(self, text, prog, line, col, wrap, ok=0):
wrapped = 0
startline = line
chars = text.get("%d.0" % line, "%d.0" % (line+1))
while chars:
m = prog.search(chars[:-1], col)
if m:
if ok or m.end() > col:
return line, m
line = line + 1
if wrapped and line > startline:
break
col = 0
ok = 1
chars = text.get("%d.0" % line, "%d.0" % (line+1))
if not chars and wrap:
wrapped = 1
wrap = 0
line = 1
chars = text.get("1.0", "2.0")
return None
def search_backward(self, text, prog, line, col, wrap, ok=0):
wrapped = 0
startline = line
chars = text.get("%d.0" % line, "%d.0" % (line+1))
while 1:
m = search_reverse(prog, chars[:-1], col)
if m:
if ok or m.start() < col:
return line, m
line = line - 1
if wrapped and line < startline:
break
ok = 1
if line <= 0:
if not wrap:
break
wrapped = 1
wrap = 0
pos = text.index("end-1c")
line, col = map(int, pos.split("."))
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chars = text.get("%d.0" % line, "%d.0" % (line+1))
col = len(chars) - 1
return None
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def search_reverse(prog, chars, col):
'''Search backwards and return an re match object or None.
This is done by searching forwards until there is no match.
Prog: compiled re object with a search method returning a match.
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Chars: line of text, without \\n.
Col: stop index for the search; the limit for match.end().
'''
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m = prog.search(chars)
if not m:
return None
found = None
i, j = m.span() # m.start(), m.end() == match slice indexes
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while i < col and j <= col:
found = m
if i == j:
j = j+1
m = prog.search(chars, j)
if not m:
break
i, j = m.span()
return found
def get_selection(text):
'''Return tuple of 'line.col' indexes from selection or insert mark.
'''
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try:
first = text.index("sel.first")
last = text.index("sel.last")
except TclError:
first = last = None
if not first:
first = text.index("insert")
if not last:
last = first
return first, last
def get_line_col(index):
'''Return (line, col) tuple of ints from 'line.col' string.'''
line, col = map(int, index.split(".")) # Fails on invalid index
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return line, col
if __name__ == "__main__":
from unittest import main
main('idlelib.idle_test.test_searchengine', verbosity=2)