Added explanatory comments.
diff --git a/Lib/macpath.py b/Lib/macpath.py
index 30d2f27..99254ab 100644
--- a/Lib/macpath.py
+++ b/Lib/macpath.py
@@ -1,14 +1,24 @@
-# module 'macpath'
+# module 'macpath' -- pathname (or -related) operations for the Macintosh
import mac
-import string
-
from stat import *
+
+# Return true if a path is absolute.
+# On the Mac, relative paths begin with a colon,
+# but as a special case, paths with no colons at all are also relative.
+# Anything else is absolute (the string up to the first colon is the
+# volume name).
+
def isabs(s):
return ':' in s and s[0] <> ':'
+
+# Concatenate two pathnames.
+# The result is equivalent to what the second pathname would refer to
+# if the first pathname were the current directory.
+
def cat(s, t):
if (not s) or isabs(t): return t
if t[:1] = ':': t = t[1:]
@@ -18,9 +28,28 @@
s = s + ':'
return s + t
-norm_error = 'path cannot be normalized'
+
+# Split a pathname in two parts: the directory leading up to the final bit,
+# and the basename (the filename, without colons, in that directory).
+# The result (s, t) is such that cat(s, t) yields the original argument.
+
+def split(s):
+ if ':' not in s: return '', s
+ colon = 0
+ for i in range(len(s)):
+ if s[i] = ':': colon = i+1
+ return s[:colon], s[colon:]
+
+
+# Normalize a pathname: get rid of '::' sequences by backing up,
+# e.g., 'foo:bar::bletch' becomes 'foo:bletch'.
+# Raise the exception norm_error below if backing up is impossible,
+# e.g., for '::foo'.
+
+norm_error = 'macpath.norm_error: path cannot be normalized'
def norm(s):
+ import string
if ':' not in s:
return ':' + s
f = string.splitfields(s, ':')
@@ -37,10 +66,10 @@
if seg:
res.append(seg)
else:
- if not res: raise norm_error # starts with '::'
+ if not res: raise norm_error, 'path starts with ::'
del res[len(res)-1]
if not (pre or res):
- raise norm_error # starts with 'vol::'
+ raise norm_error, 'path starts with volume::'
if pre: res = pre + res
if post: res = res + post
s = res[0]
@@ -48,6 +77,9 @@
s = s + ':' + seg
return s
+
+# Return true if the pathname refers to an existing directory.
+
def isdir(s):
try:
st = mac.stat(s)
@@ -55,6 +87,9 @@
return 0
return S_ISDIR(st[ST_MODE])
+
+# Return true if the pathname refers to an existing regular file.
+
def isfile(s):
try:
st = mac.stat(s)
@@ -62,6 +97,9 @@
return 0
return S_ISREG(st[ST_MODE])
+
+# Return true if the pathname refers to an existing file or directory.
+
def exists(s):
try:
st = mac.stat(s)