[Python-checkins] python/dist/src/Doc/tut glossary.tex,,

rhettinger at users.sourceforge.net rhettinger at users.sourceforge.net
Tue Jan 11 17:14:58 CET 2005

Update of /cvsroot/python/python/dist/src/Doc/tut
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv32405

Modified Files:
      Tag: release24-maint
Log Message:
Add duck-typing to the glossary.

Index: glossary.tex
RCS file: /cvsroot/python/python/dist/src/Doc/tut/glossary.tex,v
retrieving revision
retrieving revision
diff -u -d -r1.9.4.1 -r1.9.4.2
--- glossary.tex	2 Dec 2004 08:57:19 -0000
+++ glossary.tex	11 Jan 2005 16:14:55 -0000
@@ -85,6 +85,17 @@
 can be any object with a \method{__hash__()} function, not just
 integers starting from zero.  Called a hash in Perl.
+Pythonic programming style that determines an object's type by inspection
+of its method or attribute signature rather than by explicit relationship
+to some type object ("If it looks like a duck and quacks like a duck, it
+must be a duck.")  By emphasizing interfaces rather than specific types,
+well-designed code improves its flexibility by allowing polymorphic
+substitution.  Duck-typing avoids tests using \function{type()} or
+\function{isinstance()}. Instead, it typically employs
+\function{hasattr()} tests or {}\emph{EAFP} programming.
 Easier to ask for forgiveness than permission.  This common Python

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