| rev |
line source |
|
igor@402
|
1 \chapter{Customising the output of Mercurial}
|
|
igor@402
|
2 \label{chap:template}
|
|
igor@402
|
3
|
|
igor@402
|
4 Mercurial provides a powerful mechanism to let you control how it
|
|
igor@402
|
5 displays information. The mechanism is based on templates. You can
|
|
igor@402
|
6 use templates to generate specific output for a single command, or to
|
|
igor@402
|
7 customise the entire appearance of the built-in web interface.
|
|
igor@402
|
8
|
|
igor@402
|
9 \section{Using precanned output styles}
|
|
igor@402
|
10 \label{sec:style}
|
|
igor@402
|
11
|
|
igor@402
|
12 Packaged with Mercurial are some output styles that you can use
|
|
igor@402
|
13 immediately. A style is simply a precanned template that someone
|
|
igor@402
|
14 wrote and installed somewhere that Mercurial can find.
|
|
igor@402
|
15
|
|
igor@402
|
16 Before we take a look at Mercurial's bundled styles, let's review its
|
|
igor@402
|
17 normal output.
|
|
igor@402
|
18
|
|
igor@402
|
19 \interaction{template.simple.normal}
|
|
igor@402
|
20
|
|
igor@402
|
21 This is somewhat informative, but it takes up a lot of space---five
|
|
igor@402
|
22 lines of output per changeset. The \texttt{compact} style reduces
|
|
igor@402
|
23 this to three lines, presented in a sparse manner.
|
|
igor@402
|
24
|
|
igor@402
|
25 \interaction{template.simple.compact}
|
|
igor@402
|
26
|
|
igor@402
|
27 The \texttt{changelog} style hints at the expressive power of
|
|
igor@402
|
28 Mercurial's templating engine. This style attempts to follow the GNU
|
|
igor@402
|
29 Project's changelog guidelines\cite{web:changelog}.
|
|
igor@402
|
30
|
|
igor@402
|
31 \interaction{template.simple.changelog}
|
|
igor@402
|
32
|
|
igor@402
|
33 You will not be shocked to learn that Mercurial's default output style
|
|
igor@402
|
34 is named \texttt{default}.
|
|
igor@402
|
35
|
|
igor@402
|
36 \subsection{Setting a default style}
|
|
igor@402
|
37
|
|
igor@402
|
38 You can modify the output style that Mercurial will use for every
|
|
igor@402
|
39 command by editing your \hgrc\ file, naming the style you would
|
|
igor@402
|
40 prefer to use.
|
|
igor@402
|
41
|
|
igor@402
|
42 \begin{codesample2}
|
|
igor@402
|
43 [ui]
|
|
igor@402
|
44 style = compact
|
|
igor@402
|
45 \end{codesample2}
|
|
igor@402
|
46
|
|
igor@402
|
47 If you write a style of your own, you can use it by either providing
|
|
igor@402
|
48 the path to your style file, or copying your style file into a
|
|
igor@402
|
49 location where Mercurial can find it (typically the \texttt{templates}
|
|
igor@402
|
50 subdirectory of your Mercurial install directory).
|
|
igor@402
|
51
|
|
igor@402
|
52 \section{Commands that support styles and templates}
|
|
igor@402
|
53
|
|
igor@402
|
54 All of Mercurial's ``\texttt{log}-like'' commands let you use styles
|
|
igor@402
|
55 and templates: \hgcmd{incoming}, \hgcmd{log}, \hgcmd{outgoing}, and
|
|
igor@402
|
56 \hgcmd{tip}.
|
|
igor@402
|
57
|
|
igor@402
|
58 As I write this manual, these are so far the only commands that
|
|
igor@402
|
59 support styles and templates. Since these are the most important
|
|
igor@402
|
60 commands that need customisable output, there has been little pressure
|
|
igor@402
|
61 from the Mercurial user community to add style and template support to
|
|
igor@402
|
62 other commands.
|
|
igor@402
|
63
|
|
igor@402
|
64 \section{The basics of templating}
|
|
igor@402
|
65
|
|
igor@402
|
66 At its simplest, a Mercurial template is a piece of text. Some of the
|
|
igor@402
|
67 text never changes, while other parts are \emph{expanded}, or replaced
|
|
igor@402
|
68 with new text, when necessary.
|
|
igor@402
|
69
|
|
igor@402
|
70 Before we continue, let's look again at a simple example of
|
|
igor@402
|
71 Mercurial's normal output.
|
|
igor@402
|
72
|
|
igor@402
|
73 \interaction{template.simple.normal}
|
|
igor@402
|
74
|
|
igor@402
|
75 Now, let's run the same command, but using a template to change its
|
|
igor@402
|
76 output.
|
|
igor@402
|
77
|
|
igor@402
|
78 \interaction{template.simple.simplest}
|
|
igor@402
|
79
|
|
igor@402
|
80 The example above illustrates the simplest possible template; it's
|
|
igor@402
|
81 just a piece of static text, printed once for each changeset. The
|
|
igor@402
|
82 \hgopt{log}{--template} option to the \hgcmd{log} command tells
|
|
igor@402
|
83 Mercurial to use the given text as the template when printing each
|
|
igor@402
|
84 changeset.
|
|
igor@402
|
85
|
|
igor@402
|
86 Notice that the template string above ends with the text
|
|
igor@402
|
87 ``\Verb+\n+''. This is an \emph{escape sequence}, telling Mercurial
|
|
igor@402
|
88 to print a newline at the end of each template item. If you omit this
|
|
igor@402
|
89 newline, Mercurial will run each piece of output together. See
|
|
igor@402
|
90 section~\ref{sec:template:escape} for more details of escape sequences.
|
|
igor@402
|
91
|
|
igor@402
|
92 A template that prints a fixed string of text all the time isn't very
|
|
igor@402
|
93 useful; let's try something a bit more complex.
|
|
igor@402
|
94
|
|
igor@402
|
95 \interaction{template.simple.simplesub}
|
|
igor@402
|
96
|
|
igor@402
|
97 As you can see, the string ``\Verb+{desc}+'' in the template has been
|
|
igor@402
|
98 replaced in the output with the description of each changeset. Every
|
|
igor@402
|
99 time Mercurial finds text enclosed in curly braces (``\texttt{\{}''
|
|
igor@402
|
100 and ``\texttt{\}}''), it will try to replace the braces and text with
|
|
igor@402
|
101 the expansion of whatever is inside. To print a literal curly brace,
|
|
igor@402
|
102 you must escape it, as described in section~\ref{sec:template:escape}.
|
|
igor@402
|
103
|
|
igor@402
|
104 \section{Common template keywords}
|
|
igor@402
|
105 \label{sec:template:keyword}
|
|
igor@402
|
106
|
|
igor@402
|
107 You can start writing simple templates immediately using the keywords
|
|
igor@402
|
108 below.
|
|
igor@402
|
109
|
|
igor@402
|
110 \begin{itemize}
|
|
igor@402
|
111 \item[\tplkword{author}] String. The unmodified author of the changeset.
|
|
igor@402
|
112 \item[\tplkword{branches}] String. The name of the branch on which
|
|
igor@402
|
113 the changeset was committed. Will be empty if the branch name was
|
|
igor@402
|
114 \texttt{default}.
|
|
igor@402
|
115 \item[\tplkword{date}] Date information. The date when the changeset
|
|
igor@402
|
116 was committed. This is \emph{not} human-readable; you must pass it
|
|
igor@402
|
117 through a filter that will render it appropriately. See
|
|
igor@402
|
118 section~\ref{sec:template:filter} for more information on filters.
|
|
igor@402
|
119 The date is expressed as a pair of numbers. The first number is a
|
|
igor@402
|
120 Unix UTC timestamp (seconds since January 1, 1970); the second is
|
|
igor@402
|
121 the offset of the committer's timezone from UTC, in seconds.
|
|
igor@402
|
122 \item[\tplkword{desc}] String. The text of the changeset description.
|
|
igor@402
|
123 \item[\tplkword{files}] List of strings. All files modified, added, or
|
|
igor@402
|
124 removed by this changeset.
|
|
igor@402
|
125 \item[\tplkword{file\_adds}] List of strings. Files added by this
|
|
igor@402
|
126 changeset.
|
|
igor@402
|
127 \item[\tplkword{file\_dels}] List of strings. Files removed by this
|
|
igor@402
|
128 changeset.
|
|
igor@402
|
129 \item[\tplkword{node}] String. The changeset identification hash, as a
|
|
igor@402
|
130 40-character hexadecimal string.
|
|
igor@402
|
131 \item[\tplkword{parents}] List of strings. The parents of the
|
|
igor@402
|
132 changeset.
|
|
igor@402
|
133 \item[\tplkword{rev}] Integer. The repository-local changeset revision
|
|
igor@402
|
134 number.
|
|
igor@402
|
135 \item[\tplkword{tags}] List of strings. Any tags associated with the
|
|
igor@402
|
136 changeset.
|
|
igor@402
|
137 \end{itemize}
|
|
igor@402
|
138
|
|
igor@402
|
139 A few simple experiments will show us what to expect when we use these
|
|
igor@402
|
140 keywords; you can see the results in
|
|
igor@402
|
141 figure~\ref{fig:template:keywords}.
|
|
igor@402
|
142
|
|
igor@402
|
143 \begin{figure}
|
|
igor@402
|
144 \interaction{template.simple.keywords}
|
|
igor@402
|
145 \caption{Template keywords in use}
|
|
igor@402
|
146 \label{fig:template:keywords}
|
|
igor@402
|
147 \end{figure}
|
|
igor@402
|
148
|
|
igor@402
|
149 As we noted above, the date keyword does not produce human-readable
|
|
igor@402
|
150 output, so we must treat it specially. This involves using a
|
|
igor@402
|
151 \emph{filter}, about which more in section~\ref{sec:template:filter}.
|
|
igor@402
|
152
|
|
igor@402
|
153 \interaction{template.simple.datekeyword}
|
|
igor@402
|
154
|
|
igor@402
|
155 \section{Escape sequences}
|
|
igor@402
|
156 \label{sec:template:escape}
|
|
igor@402
|
157
|
|
igor@402
|
158 Mercurial's templating engine recognises the most commonly used escape
|
|
igor@402
|
159 sequences in strings. When it sees a backslash (``\Verb+\+'')
|
|
igor@402
|
160 character, it looks at the following character and substitutes the two
|
|
igor@402
|
161 characters with a single replacement, as described below.
|
|
igor@402
|
162
|
|
igor@402
|
163 \begin{itemize}
|
|
igor@402
|
164 \item[\Verb+\textbackslash\textbackslash+] Backslash, ``\Verb+\+'',
|
|
igor@402
|
165 ASCII~134.
|
|
igor@402
|
166 \item[\Verb+\textbackslash n+] Newline, ASCII~12.
|
|
igor@402
|
167 \item[\Verb+\textbackslash r+] Carriage return, ASCII~15.
|
|
igor@402
|
168 \item[\Verb+\textbackslash t+] Tab, ASCII~11.
|
|
igor@402
|
169 \item[\Verb+\textbackslash v+] Vertical tab, ASCII~13.
|
|
igor@402
|
170 \item[\Verb+\textbackslash \{+] Open curly brace, ``\Verb+{+'', ASCII~173.
|
|
igor@402
|
171 \item[\Verb+\textbackslash \}+] Close curly brace, ``\Verb+}+'', ASCII~175.
|
|
igor@402
|
172 \end{itemize}
|
|
igor@402
|
173
|
|
igor@402
|
174 As indicated above, if you want the expansion of a template to contain
|
|
igor@402
|
175 a literal ``\Verb+\+'', ``\Verb+{+'', or ``\Verb+{+'' character, you
|
|
igor@402
|
176 must escape it.
|
|
igor@402
|
177
|
|
igor@402
|
178 \section{Filtering keywords to change their results}
|
|
igor@402
|
179 \label{sec:template:filter}
|
|
igor@402
|
180
|
|
igor@402
|
181 Some of the results of template expansion are not immediately easy to
|
|
igor@402
|
182 use. Mercurial lets you specify an optional chain of \emph{filters}
|
|
igor@402
|
183 to modify the result of expanding a keyword. You have already seen a
|
|
igor@402
|
184 common filter, \tplkwfilt{date}{isodate}, in action above, to make a
|
|
igor@402
|
185 date readable.
|
|
igor@402
|
186
|
|
igor@402
|
187 Below is a list of the most commonly used filters that Mercurial
|
|
igor@402
|
188 supports. While some filters can be applied to any text, others can
|
|
igor@402
|
189 only be used in specific circumstances. The name of each filter is
|
|
igor@402
|
190 followed first by an indication of where it can be used, then a
|
|
igor@402
|
191 description of its effect.
|
|
igor@402
|
192
|
|
igor@402
|
193 \begin{itemize}
|
|
igor@402
|
194 \item[\tplfilter{addbreaks}] Any text. Add an XHTML ``\Verb+<br/>+''
|
|
igor@402
|
195 tag before the end of every line except the last. For example,
|
|
igor@402
|
196 ``\Verb+foo\nbar+'' becomes ``\Verb+foo<br/>\nbar+''.
|
|
igor@402
|
197 \item[\tplkwfilt{date}{age}] \tplkword{date} keyword. Render the
|
|
igor@402
|
198 age of the date, relative to the current time. Yields a string like
|
|
igor@402
|
199 ``\Verb+10 minutes+''.
|
|
igor@402
|
200 \item[\tplfilter{basename}] Any text, but most useful for the
|
|
igor@402
|
201 \tplkword{files} keyword and its relatives. Treat the text as a
|
|
igor@402
|
202 path, and return the basename. For example, ``\Verb+foo/bar/baz+''
|
|
igor@402
|
203 becomes ``\Verb+baz+''.
|
|
igor@402
|
204 \item[\tplkwfilt{date}{date}] \tplkword{date} keyword. Render a date
|
|
igor@402
|
205 in a similar format to the Unix \tplkword{date} command, but with
|
|
igor@402
|
206 timezone included. Yields a string like
|
|
igor@402
|
207 ``\Verb+Mon Sep 04 15:13:13 2006 -0700+''.
|
|
igor@402
|
208 \item[\tplkwfilt{author}{domain}] Any text, but most useful for the
|
|
igor@402
|
209 \tplkword{author} keyword. Finds the first string that looks like
|
|
igor@402
|
210 an email address, and extract just the domain component. For
|
|
igor@402
|
211 example, ``\Verb+Bryan O'Sullivan <bos@serpentine.com>+'' becomes
|
|
igor@402
|
212 ``\Verb+serpentine.com+''.
|
|
igor@402
|
213 \item[\tplkwfilt{author}{email}] Any text, but most useful for the
|
|
igor@402
|
214 \tplkword{author} keyword. Extract the first string that looks like
|
|
igor@402
|
215 an email address. For example,
|
|
igor@402
|
216 ``\Verb+Bryan O'Sullivan <bos@serpentine.com>+'' becomes
|
|
igor@402
|
217 ``\Verb+bos@serpentine.com+''.
|
|
igor@402
|
218 \item[\tplfilter{escape}] Any text. Replace the special XML/XHTML
|
|
igor@402
|
219 characters ``\Verb+&+'', ``\Verb+<+'' and ``\Verb+>+'' with
|
|
igor@402
|
220 XML entities.
|
|
igor@402
|
221 \item[\tplfilter{fill68}] Any text. Wrap the text to fit in 68
|
|
igor@402
|
222 columns. This is useful before you pass text through the
|
|
igor@402
|
223 \tplfilter{tabindent} filter, and still want it to fit in an
|
|
igor@402
|
224 80-column fixed-font window.
|
|
igor@402
|
225 \item[\tplfilter{fill76}] Any text. Wrap the text to fit in 76
|
|
igor@402
|
226 columns.
|
|
igor@402
|
227 \item[\tplfilter{firstline}] Any text. Yield the first line of text,
|
|
igor@402
|
228 without any trailing newlines.
|
|
igor@402
|
229 \item[\tplkwfilt{date}{hgdate}] \tplkword{date} keyword. Render the
|
|
igor@402
|
230 date as a pair of readable numbers. Yields a string like
|
|
igor@402
|
231 ``\Verb+1157407993 25200+''.
|
|
igor@402
|
232 \item[\tplkwfilt{date}{isodate}] \tplkword{date} keyword. Render the
|
|
igor@402
|
233 date as a text string in ISO~8601 format. Yields a string like
|
|
igor@402
|
234 ``\Verb+2006-09-04 15:13:13 -0700+''.
|
|
igor@402
|
235 \item[\tplfilter{obfuscate}] Any text, but most useful for the
|
|
igor@402
|
236 \tplkword{author} keyword. Yield the input text rendered as a
|
|
igor@402
|
237 sequence of XML entities. This helps to defeat some particularly
|
|
igor@402
|
238 stupid screen-scraping email harvesting spambots.
|
|
igor@402
|
239 \item[\tplkwfilt{author}{person}] Any text, but most useful for the
|
|
igor@402
|
240 \tplkword{author} keyword. Yield the text before an email address.
|
|
igor@402
|
241 For example, ``\Verb+Bryan O'Sullivan <bos@serpentine.com>+''
|
|
igor@402
|
242 becomes ``\Verb+Bryan O'Sullivan+''.
|
|
igor@402
|
243 \item[\tplkwfilt{date}{rfc822date}] \tplkword{date} keyword. Render a
|
|
igor@402
|
244 date using the same format used in email headers. Yields a string
|
|
igor@402
|
245 like ``\Verb+Mon, 04 Sep 2006 15:13:13 -0700+''.
|
|
igor@402
|
246 \item[\tplkwfilt{node}{short}] Changeset hash. Yield the short form
|
|
igor@402
|
247 of a changeset hash, i.e.~a 12-byte hexadecimal string.
|
|
igor@402
|
248 \item[\tplkwfilt{date}{shortdate}] \tplkword{date} keyword. Render
|
|
igor@402
|
249 the year, month, and day of the date. Yields a string like
|
|
igor@402
|
250 ``\Verb+2006-09-04+''.
|
|
igor@402
|
251 \item[\tplfilter{strip}] Any text. Strip all leading and trailing
|
|
igor@402
|
252 whitespace from the string.
|
|
igor@402
|
253 \item[\tplfilter{tabindent}] Any text. Yield the text, with every line
|
|
igor@402
|
254 except the first starting with a tab character.
|
|
igor@402
|
255 \item[\tplfilter{urlescape}] Any text. Escape all characters that are
|
|
igor@402
|
256 considered ``special'' by URL parsers. For example, \Verb+foo bar+
|
|
igor@402
|
257 becomes \Verb+foo%20bar+.
|
|
igor@402
|
258 \item[\tplkwfilt{author}{user}] Any text, but most useful for the
|
|
igor@402
|
259 \tplkword{author} keyword. Return the ``user'' portion of an email
|
|
igor@402
|
260 address. For example,
|
|
igor@402
|
261 ``\Verb+Bryan O'Sullivan <bos@serpentine.com>+'' becomes
|
|
igor@402
|
262 ``\Verb+bos+''.
|
|
igor@402
|
263 \end{itemize}
|
|
igor@402
|
264
|
|
igor@402
|
265 \begin{figure}
|
|
igor@402
|
266 \interaction{template.simple.manyfilters}
|
|
igor@402
|
267 \caption{Template filters in action}
|
|
igor@402
|
268 \label{fig:template:filters}
|
|
igor@402
|
269 \end{figure}
|
|
igor@402
|
270
|
|
igor@402
|
271 \begin{note}
|
|
igor@402
|
272 If you try to apply a filter to a piece of data that it cannot
|
|
igor@402
|
273 process, Mercurial will fail and print a Python exception. For
|
|
igor@402
|
274 example, trying to run the output of the \tplkword{desc} keyword
|
|
igor@402
|
275 into the \tplkwfilt{date}{isodate} filter is not a good idea.
|
|
igor@402
|
276 \end{note}
|
|
igor@402
|
277
|
|
igor@402
|
278 \subsection{Combining filters}
|
|
igor@402
|
279
|
|
igor@402
|
280 It is easy to combine filters to yield output in the form you would
|
|
igor@402
|
281 like. The following chain of filters tidies up a description, then
|
|
igor@402
|
282 makes sure that it fits cleanly into 68 columns, then indents it by a
|
|
igor@402
|
283 further 8~characters (at least on Unix-like systems, where a tab is
|
|
igor@402
|
284 conventionally 8~characters wide).
|
|
igor@402
|
285
|
|
igor@402
|
286 \interaction{template.simple.combine}
|
|
igor@402
|
287
|
|
igor@402
|
288 Note the use of ``\Verb+\t+'' (a tab character) in the template to
|
|
igor@402
|
289 force the first line to be indented; this is necessary since
|
|
igor@402
|
290 \tplkword{tabindent} indents all lines \emph{except} the first.
|
|
igor@402
|
291
|
|
igor@402
|
292 Keep in mind that the order of filters in a chain is significant. The
|
|
igor@402
|
293 first filter is applied to the result of the keyword; the second to
|
|
igor@402
|
294 the result of the first filter; and so on. For example, using
|
|
igor@402
|
295 \Verb+fill68|tabindent+ gives very different results from
|
|
igor@402
|
296 \Verb+tabindent|fill68+.
|
|
igor@402
|
297
|
|
igor@402
|
298
|
|
igor@402
|
299 \section{From templates to styles}
|
|
igor@402
|
300
|
|
igor@402
|
301 A command line template provides a quick and simple way to format some
|
|
igor@402
|
302 output. Templates can become verbose, though, and it's useful to be
|
|
igor@402
|
303 able to give a template a name. A style file is a template with a
|
|
igor@402
|
304 name, stored in a file.
|
|
igor@402
|
305
|
|
igor@402
|
306 More than that, using a style file unlocks the power of Mercurial's
|
|
igor@402
|
307 templating engine in ways that are not possible using the command line
|
|
igor@402
|
308 \hgopt{log}{--template} option.
|
|
igor@402
|
309
|
|
igor@402
|
310 \subsection{The simplest of style files}
|
|
igor@402
|
311
|
|
igor@402
|
312 Our simple style file contains just one line:
|
|
igor@402
|
313
|
|
igor@402
|
314 \interaction{template.simple.rev}
|
|
igor@402
|
315
|
|
igor@402
|
316 This tells Mercurial, ``if you're printing a changeset, use the text
|
|
igor@402
|
317 on the right as the template''.
|
|
igor@402
|
318
|
|
igor@402
|
319 \subsection{Style file syntax}
|
|
igor@402
|
320
|
|
igor@402
|
321 The syntax rules for a style file are simple.
|
|
igor@402
|
322
|
|
igor@402
|
323 \begin{itemize}
|
|
igor@402
|
324 \item The file is processed one line at a time.
|
|
igor@402
|
325
|
|
igor@402
|
326 \item Leading and trailing white space are ignored.
|
|
igor@402
|
327
|
|
igor@402
|
328 \item Empty lines are skipped.
|
|
igor@402
|
329
|
|
igor@402
|
330 \item If a line starts with either of the characters ``\texttt{\#}'' or
|
|
igor@402
|
331 ``\texttt{;}'', the entire line is treated as a comment, and skipped
|
|
igor@402
|
332 as if empty.
|
|
igor@402
|
333
|
|
igor@402
|
334 \item A line starts with a keyword. This must start with an
|
|
igor@402
|
335 alphabetic character or underscore, and can subsequently contain any
|
|
igor@402
|
336 alphanumeric character or underscore. (In regexp notation, a
|
|
igor@402
|
337 keyword must match \Verb+[A-Za-z_][A-Za-z0-9_]*+.)
|
|
igor@402
|
338
|
|
igor@402
|
339 \item The next element must be an ``\texttt{=}'' character, which can
|
|
igor@402
|
340 be preceded or followed by an arbitrary amount of white space.
|
|
igor@402
|
341
|
|
igor@402
|
342 \item If the rest of the line starts and ends with matching quote
|
|
igor@402
|
343 characters (either single or double quote), it is treated as a
|
|
igor@402
|
344 template body.
|
|
igor@402
|
345
|
|
igor@402
|
346 \item If the rest of the line \emph{does not} start with a quote
|
|
igor@402
|
347 character, it is treated as the name of a file; the contents of this
|
|
igor@402
|
348 file will be read and used as a template body.
|
|
igor@402
|
349 \end{itemize}
|
|
igor@402
|
350
|
|
igor@402
|
351 \section{Style files by example}
|
|
igor@402
|
352
|
|
igor@402
|
353 To illustrate how to write a style file, we will construct a few by
|
|
igor@402
|
354 example. Rather than provide a complete style file and walk through
|
|
igor@402
|
355 it, we'll mirror the usual process of developing a style file by
|
|
igor@402
|
356 starting with something very simple, and walking through a series of
|
|
igor@402
|
357 successively more complete examples.
|
|
igor@402
|
358
|
|
igor@402
|
359 \subsection{Identifying mistakes in style files}
|
|
igor@402
|
360
|
|
igor@402
|
361 If Mercurial encounters a problem in a style file you are working on,
|
|
igor@402
|
362 it prints a terse error message that, once you figure out what it
|
|
igor@402
|
363 means, is actually quite useful.
|
|
igor@402
|
364
|
|
igor@402
|
365 \interaction{template.svnstyle.syntax.input}
|
|
igor@402
|
366
|
|
igor@402
|
367 Notice that \filename{broken.style} attempts to define a
|
|
igor@402
|
368 \texttt{changeset} keyword, but forgets to give any content for it.
|
|
igor@402
|
369 When instructed to use this style file, Mercurial promptly complains.
|
|
igor@402
|
370
|
|
igor@402
|
371 \interaction{template.svnstyle.syntax.error}
|
|
igor@402
|
372
|
|
igor@402
|
373 This error message looks intimidating, but it is not too hard to
|
|
igor@402
|
374 follow.
|
|
igor@402
|
375
|
|
igor@402
|
376 \begin{itemize}
|
|
igor@402
|
377 \item The first component is simply Mercurial's way of saying ``I am
|
|
igor@402
|
378 giving up''.
|
|
igor@402
|
379 \begin{codesample4}
|
|
igor@402
|
380 \textbf{abort:} broken.style:1: parse error
|
|
igor@402
|
381 \end{codesample4}
|
|
igor@402
|
382
|
|
igor@402
|
383 \item Next comes the name of the style file that contains the error.
|
|
igor@402
|
384 \begin{codesample4}
|
|
igor@402
|
385 abort: \textbf{broken.style}:1: parse error
|
|
igor@402
|
386 \end{codesample4}
|
|
igor@402
|
387
|
|
igor@402
|
388 \item Following the file name is the line number where the error was
|
|
igor@402
|
389 encountered.
|
|
igor@402
|
390 \begin{codesample4}
|
|
igor@402
|
391 abort: broken.style:\textbf{1}: parse error
|
|
igor@402
|
392 \end{codesample4}
|
|
igor@402
|
393
|
|
igor@402
|
394 \item Finally, a description of what went wrong.
|
|
igor@402
|
395 \begin{codesample4}
|
|
igor@402
|
396 abort: broken.style:1: \textbf{parse error}
|
|
igor@402
|
397 \end{codesample4}
|
|
igor@402
|
398 The description of the problem is not always clear (as in this
|
|
igor@402
|
399 case), but even when it is cryptic, it is almost always trivial to
|
|
igor@402
|
400 visually inspect the offending line in the style file and see what
|
|
igor@402
|
401 is wrong.
|
|
igor@402
|
402 \end{itemize}
|
|
igor@402
|
403
|
|
igor@402
|
404 \subsection{Uniquely identifying a repository}
|
|
igor@402
|
405
|
|
igor@402
|
406 If you would like to be able to identify a Mercurial repository
|
|
igor@402
|
407 ``fairly uniquely'' using a short string as an identifier, you can
|
|
igor@402
|
408 use the first revision in the repository.
|
|
igor@402
|
409 \interaction{template.svnstyle.id}
|
|
igor@402
|
410 This is not guaranteed to be unique, but it is nevertheless useful in
|
|
igor@402
|
411 many cases.
|
|
igor@402
|
412 \begin{itemize}
|
|
igor@402
|
413 \item It will not work in a completely empty repository, because such
|
|
igor@402
|
414 a repository does not have a revision~zero.
|
|
igor@402
|
415 \item Neither will it work in the (extremely rare) case where a
|
|
igor@402
|
416 repository is a merge of two or more formerly independent
|
|
igor@402
|
417 repositories, and you still have those repositories around.
|
|
igor@402
|
418 \end{itemize}
|
|
igor@402
|
419 Here are some uses to which you could put this identifier:
|
|
igor@402
|
420 \begin{itemize}
|
|
igor@402
|
421 \item As a key into a table for a database that manages repositories
|
|
igor@402
|
422 on a server.
|
|
igor@402
|
423 \item As half of a \{\emph{repository~ID}, \emph{revision~ID}\} tuple.
|
|
igor@402
|
424 Save this information away when you run an automated build or other
|
|
igor@402
|
425 activity, so that you can ``replay'' the build later if necessary.
|
|
igor@402
|
426 \end{itemize}
|
|
igor@402
|
427
|
|
igor@402
|
428 \subsection{Mimicking Subversion's output}
|
|
igor@402
|
429
|
|
igor@402
|
430 Let's try to emulate the default output format used by another
|
|
igor@402
|
431 revision control tool, Subversion.
|
|
igor@402
|
432 \interaction{template.svnstyle.short}
|
|
igor@402
|
433
|
|
igor@402
|
434 Since Subversion's output style is fairly simple, it is easy to
|
|
igor@402
|
435 copy-and-paste a hunk of its output into a file, and replace the text
|
|
igor@402
|
436 produced above by Subversion with the template values we'd like to see
|
|
igor@402
|
437 expanded.
|
|
igor@402
|
438 \interaction{template.svnstyle.template}
|
|
igor@402
|
439
|
|
igor@402
|
440 There are a few small ways in which this template deviates from the
|
|
igor@402
|
441 output produced by Subversion.
|
|
igor@402
|
442 \begin{itemize}
|
|
igor@402
|
443 \item Subversion prints a ``readable'' date (the ``\texttt{Wed, 27 Sep
|
|
igor@402
|
444 2006}'' in the example output above) in parentheses. Mercurial's
|
|
igor@402
|
445 templating engine does not provide a way to display a date in this
|
|
igor@402
|
446 format without also printing the time and time zone.
|
|
igor@402
|
447 \item We emulate Subversion's printing of ``separator'' lines full of
|
|
igor@402
|
448 ``\texttt{-}'' characters by ending the template with such a line.
|
|
igor@402
|
449 We use the templating engine's \tplkword{header} keyword to print a
|
|
igor@402
|
450 separator line as the first line of output (see below), thus
|
|
igor@402
|
451 achieving similar output to Subversion.
|
|
igor@402
|
452 \item Subversion's output includes a count in the header of the number
|
|
igor@402
|
453 of lines in the commit message. We cannot replicate this in
|
|
igor@402
|
454 Mercurial; the templating engine does not currently provide a filter
|
|
igor@402
|
455 that counts the number of items it is passed.
|
|
igor@402
|
456 \end{itemize}
|
|
igor@402
|
457 It took me no more than a minute or two of work to replace literal
|
|
igor@402
|
458 text from an example of Subversion's output with some keywords and
|
|
igor@402
|
459 filters to give the template above. The style file simply refers to
|
|
igor@402
|
460 the template.
|
|
igor@402
|
461 \interaction{template.svnstyle.style}
|
|
igor@402
|
462
|
|
igor@402
|
463 We could have included the text of the template file directly in the
|
|
igor@402
|
464 style file by enclosing it in quotes and replacing the newlines with
|
|
igor@402
|
465 ``\verb!\n!'' sequences, but it would have made the style file too
|
|
igor@402
|
466 difficult to read. Readability is a good guide when you're trying to
|
|
igor@402
|
467 decide whether some text belongs in a style file, or in a template
|
|
igor@402
|
468 file that the style file points to. If the style file will look too
|
|
igor@402
|
469 big or cluttered if you insert a literal piece of text, drop it into a
|
|
igor@402
|
470 template instead.
|
|
igor@402
|
471
|
|
igor@402
|
472 %%% Local Variables:
|
|
igor@402
|
473 %%% mode: latex
|
|
igor@402
|
474 %%% TeX-master: "00book"
|
|
igor@402
|
475 %%% End:
|
