diff options
Diffstat (limited to 'Doc/lib/liboptparse.tex')
| -rw-r--r-- | Doc/lib/liboptparse.tex | 40 |
1 files changed, 20 insertions, 20 deletions
diff --git a/Doc/lib/liboptparse.tex b/Doc/lib/liboptparse.tex index 12af778..befc361 100644 --- a/Doc/lib/liboptparse.tex +++ b/Doc/lib/liboptparse.tex @@ -82,14 +82,14 @@ First, we need to establish some terminology. a chunk of text that a user enters on the command-line, and that the shell passes to \cfunction{execl()} or \cfunction{execv()}. In Python, arguments are elements of -\var{sys.argv[1:]}. (\var{sys.argv[0]} is the name of the program +\code{sys.argv[1:]}. (\code{sys.argv[0]} is the name of the program being executed; in the context of parsing arguments, it's not very important.) \UNIX{} shells also use the term ``word''. It is occasionally desirable to use an argument list other than -\var{sys.argv[1:]}, so you should read ``argument'' as ``an element of -\var{sys.argv[1:]}, or of some other list provided as a substitute for -\var{sys.argv[1:]}''. +\code{sys.argv[1:]}, so you should read ``argument'' as ``an element of +\code{sys.argv[1:]}, or of some other list provided as a substitute for +\code{sys.argv[1:]}''. \term{option} an argument used to supply extra information to guide or customize @@ -306,10 +306,10 @@ args = ["-f", "foo.txt"] \end{verbatim} (Note that if you don't pass an argument list to -\function{parse_args()}, it automatically uses \var{sys.argv[1:]}.) +\function{parse_args()}, it automatically uses \code{sys.argv[1:]}.) When \module{optparse} sees the \programopt{-f}, it consumes the next -argument---\code{foo.txt}---and stores it in the \var{filename} +argument---\code{foo.txt}---and stores it in the \member{filename} attribute of a special object. That object is the first return value from \function{parse_args()}, so: @@ -354,9 +354,9 @@ parser.add_option("-f", "--file", dest="filename") If you don't supply a destination, \module{optparse} figures out a sensible default from the option strings: if the first long option string is \longprogramopt{foo-bar}, then the default destination is -\var{foo_bar}. If there are no long option strings, +\member{foo_bar}. If there are no long option strings, \module{optparse} looks at the first short option: the default -destination for \programopt{-f} is \var{f}. +destination for \programopt{-f} is \member{f}. Adding types is fairly easy; please refer to section~\ref{optparse-adding-types}, ``Adding new types.'' @@ -380,8 +380,8 @@ perfectly OK. (It just means you have to be a bit careful when setting default values---see below.) When \module{optparse} sees \programopt{-v} on the command line, it sets -\var{options.verbose} to \code{True}; when it sees \programopt{-q}, it -sets \var{options.verbose} to \code{False}. +\code{options.verbose} to \code{True}; when it sees \programopt{-q}, it +sets \code{options.verbose} to \code{False}. \subsubsection{Setting default values\label{optparse-setting-default-values}} @@ -394,7 +394,7 @@ address that need, \module{optparse} lets you supply a default value for each destination, which is assigned before the command-line is parsed. First, consider the verbose/quiet example. If we want -\module{optparse} to set \var{verbose} to \code{True} unless +\module{optparse} to set \member{verbose} to \code{True} unless \programopt{-q} is seen, then we can do this: \begin{verbatim} @@ -411,7 +411,7 @@ parser.add_option("-q", action="store_false", dest="verbose", default=True) Those are equivalent because you're supplying a default value for the option's \emph{destination}, and these two options happen to have the same -destination (the \var{verbose} variable). +destination (the \member{verbose} variable). Consider this: @@ -420,7 +420,7 @@ parser.add_option("-v", action="store_true", dest="verbose", default=False) parser.add_option("-q", action="store_false", dest="verbose", default=True) \end{verbatim} -Again, the default value for \var{verbose} will be \code{True}: the last +Again, the default value for \member{verbose} will be \code{True}: the last default value supplied for any particular destination is the one that counts. @@ -428,7 +428,7 @@ counts. The last feature that you will use in every script is \module{optparse}'s ability to generate help messages. All you have -to do is supply a \var{help} value when you add an option. Let's +to do is supply a \var{help} argument when you add an option. Let's create a new parser and populate it with user-friendly (documented) options: @@ -738,7 +738,7 @@ parser.parse_args() \end{verbatim} one of the first things \module{optparse} does is create a -\var{values} object: +\code{values} object: \begin{verbatim} values = Values() @@ -786,7 +786,7 @@ value according to \var{type} and stored in \var{dest}. If \code{nargs > 1}, multiple arguments will be consumed from the command line; all will be converted according to \var{type} and stored to \var{dest} as a tuple. See section~\ref{optparse-option-types}, -``Option types'' below. +``Option types,'' below. If \var{choices} (a sequence of strings) is supplied, the type defaults to ``choice''. @@ -795,9 +795,9 @@ If \var{type} is not supplied, it defaults to ``string''. If \var{dest} is not supplied, \module{optparse} derives a destination from the first long option strings (e.g., -\longprogramopt{foo-bar} becomes \var{foo_bar}). If there are no long +\longprogramopt{foo-bar} becomes \member{foo_bar}). If there are no long option strings, \module{optparse} derives a destination from the first -short option string (e.g., \programopt{-f} becomes \var{f}). +short option string (e.g., \programopt{-f} becomes \member{f}). Example: @@ -1217,7 +1217,7 @@ is the \class{Option} instance that's calling the callback. \term{opt} is the option string seen on the command-line that's triggering the callback. (If an abbreviated long option was used, \var{opt} will be -the full, canonical option string---e.g. if the user puts +the full, canonical option string---for example, if the user puts \longprogramopt{foo} on the command-line as an abbreviation for \longprogramopt{foobar}, then \var{opt} will be \longprogramopt{foobar}.) @@ -1676,7 +1676,7 @@ You'll have to The second, much more complex, possibility is to override the command-line syntax implemented by \module{optparse}. In this case, you'd leave the whole machinery of option actions and types alone, but -rewrite the code that processes \var{sys.argv}. You'll need to +rewrite the code that processes \code{sys.argv}. You'll need to subclass \class{OptionParser} in any case; depending on how radical a rewrite you want, you'll probably need to override one or all of \method{parse_args()}, \method{_process_long_opt()}, and |