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Tweak the wording. Improve examples. Make more brief.

This commit is contained in:
Raymond Hettinger 2004-09-14 06:32:20 +00:00
parent 29c6a79b7d
commit 879ddf30d0
1 changed files with 15 additions and 26 deletions
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Doc/tut/tut.tex
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@ -4841,26 +4841,26 @@ with group separators:
The \ulink{\module{string}}{../lib/module-string.html} module includes a
versatile \class{Template} class with a simplified syntax suitable for
editing by end-users. This allows users to customize their applications
without having to alter the Python program.
without having to alter the application.
The format uses \samp{\$} for placeholder names that are valid Python
The format uses placeholder names formed by \samp{\$} with valid Python
identifiers (alphanumeric characters and underscores). Surrounding the
placeholder with braces allows it to be followed by more alphanumeric letters
with no intervening spaces. \samp{\$\$} is the way to create a single escaped
with no intervening spaces. Writing \samp{\$\$} creates a single escaped
\samp{\$}:
\begin{verbatim}
>>> from string import Template
>>> t = Template('${village}folk send $$10 to $cause.')
>>> t.substitute(village='nottingham', cause='the ditch fund')
'nottinghamfolk send $10 to the ditch fund.'
>>> t.substitute(village='Nottingham', cause='the ditch fund')
'Nottinghamfolk send $10 to the ditch fund.'
\end{verbatim}
The \method{substitute} method raises a \exception{KeyError} when a
placeholder is not supplied in a dictionary or a keyword argument.
For mail-merge style applications, user supplied data may be incomplete
and the \method{safe_substitute} method may be more appropriate --- it
will leave placeholders unchanged if data is missing:
placeholder is not supplied in a dictionary or a keyword argument. For
mail-merge style applications, user supplied data may be incomplete and the
\method{safe_substitute} method may be more appropriate --- it will leave
placeholders unchanged if data is missing:
\begin{verbatim}
>>> t = Template('Return the $item to $owner.')
@ -4875,7 +4875,7 @@ KeyError: 'owner'
Template subclasses can specify a custom delimiter. For example, a batch
renaming utility for a photo browser may elect to use percent signs for
metadata such as the current date, image sequence number, or file format:
placeholders such as the current date, image sequence number, or file format:
\begin{verbatim}
>>> import time, os.path
@ -4885,11 +4885,11 @@ metadata such as the current date, image sequence number, or file format:
>>> fmt = raw_input('Enter rename style (%d-date %n-seqnum %f-format): ')
Enter rename style (%d-date %n-seqnum %f-format): Ashley_%n%f
>>> rename = BatchRename(fmt)
>>> t = BatchRename(fmt)
>>> date = time.strftime('%d%b%y')
>>> for i, filename in enumerate(photofiles):
... base, ext = os.path.splitext(filename)
... newname = rename.substitute(d=date, n=i, f=ext)
... newname = t.substitute(d=date, n=i, f=ext)
... print '%s --> %s' % (filename, newname)
img_1074.jpg --> Ashley_0.jpg
@ -4897,20 +4897,9 @@ img_1076.jpg --> Ashley_1.jpg
img_1077.jpg --> Ashley_2.jpg
\end{verbatim}
For internationalization applications, it may be appropriate to coerce all
templates to \class{unicode}. This can be done with subclassing and
overriding the \method{__init__} method:
\begin{verbatim}
>>> class UnicodeTemplate(unicode, Template):
... def __init__(self, template):
... self.template = unicode(template)
>>> t = UnicodeTemplate('Knights who say $what')
>>> t.substitute(what='Ni')
u'Knights who say Ni'
>>> t.capitalize()
u'Knights who say $what'
\end{verbatim}
Another application for templating is separating program logic from the
details of multiple output formats. The makes it possible to substitute
custom templates for XML files, plain text reports, and HMTL web reports.
\section{Working with Binary Data Record Layouts\label{binary-formats}}