added cd_correction.py

thefuck/rules/cd_correction.py

@@ -0,0 +1,85 @@
+#!/usr/bin/env python
+__author__ = "mmussomele"
+
+"""Attempts to spellcheck and correct failed cd commands"""
+
+import os
+import cd_mkdir
+from thefuck.utils import sudo_support
+
+MAX_ALLOWED_STR_DIST = 5
+
+def _get_sub_dirs(parent):
+    """Returns a list of the child directories of the given parent directory"""
+    return [child for child in os.listdir(parent) if os.path.isdir(os.path.join(parent, child))]
+
+def _dam_lev_dist():
+    """Returns a Damerau-Levenshtein distance calculator."""
+    cache = {}
+    def _calculator(first, second):
+        """
+        Calculates the Damerau-Levenshtein distance of two strings.
+        See: http://en.wikipedia.org/wiki/Damerau-Levenshtein_distance#Algorithm
+        """
+        if (first, second) in cache:
+            return cache[(first, second)]
+        else:
+            l_first = len(first)
+            l_second = len(second)
+            distances = [[0 for _ in range(l_second + 1)] for _ in range(l_first + 1)]
+            for i in range(l_first + 1):
+                distances[i][0] = i
+            for j in range(1, l_second + 1):
+                distances[0][j] = j
+            for i in range(l_first):
+                for j in range(l_second):
+                    if first[i] == second[j]:
+                        cost = 0
+                    else:
+                        cost = 1
+                    distances[i+1][j+1] = min(distances[i][j+1] + 1, 
+                                              distances[i+1][j] + 1,
+                                              distances[i][j] + cost)
+                    if i and j and first[i] == second[j-1] and first[i-1] == second[j]:
+                        distances[i][j] = min(distances[i+1][j+1],
+                                              distances[i-1][j-1] + cost)
+            cache[(first, second)] = distances[l_first][l_second]
+            return distances[l_first][l_second]
+    return _calculator
+
+_dam_lev_dist = _dam_lev_dist()
+
+@sudo_support
+def match(command, settings):
+    """Match function copied from cd_mkdir.py"""
+    return (command.script.startswith('cd ')
+        and ('no such file or directory' in command.stderr.lower()
+            or 'cd: can\'t cd to' in command.stderr.lower()))
+
+@sudo_support
+def get_new_command(command, settings):
+    """
+    Attempt to rebuild the path string by spellchecking the directories.
+    If it fails (i.e. no directories are a close enough match), then it 
+    defaults to the rules of cd_mkdir. 
+    Change sensitivity to matching by changing MAX_ALLOWED_STR_DIST. 
+    Higher values allow for larger discrepancies in path names. 
+    """
+    dest = command.script.split()[1].split(os.sep)
+    if dest[-1] == '':
+        dest = dest[:-1]
+    cwd = os.getcwd()
+    for directory in dest:
+        if directory == ".":
+            continue
+        elif directory == "..":
+            cwd = os.path.split(cwd)[0]
+            continue
+        best_match = min(_get_sub_dirs(cwd), key=lambda x: _dam_lev_dist(directory, x))
+        if _dam_lev_dist(directory, best_match) > MAX_ALLOWED_STR_DIST:
+            return cd_mkdir.get_new_command(command, settings)
+        else:
+            cwd = os.path.join(cwd, best_match)
+    return "cd {0}".format(cwd) 
+
+enabled_by_default = True