New upstream version 2019.09.01

[youtubedl] / youtube-dl.1

diff --git a/youtube-dl.1 b/youtube-dl.1
index 119ecd2ee67b1b0d97c45da23004fed633035da8..fa17c311357571462837bc8e49309826d48251c2 100644 (file)
--- a/youtube-dl.1
+++ b/youtube-dl.1
@@ -2423,6 +2423,86 @@ Incorrect:
 \[aq]PLMYEtVRpaqY00V9W81Cwmzp6N6vZqfUKD4\[aq]
 \f[]
 .fi
 \[aq]PLMYEtVRpaqY00V9W81Cwmzp6N6vZqfUKD4\[aq]
 \f[]
 .fi

+.SS Inline values
+.PP
+Extracting variables is acceptable for reducing code duplication and
+improving readability of complex expressions.
+However, you should avoid extracting variables used only once and moving
+them to opposite parts of the extractor file, which makes reading the
+linear flow difficult.
+.SS Example
+.PP
+Correct:
+.IP
+.nf
+\f[C]
+title\ =\ self._html_search_regex(r\[aq]<title>([^<]+)</title>\[aq],\ webpage,\ \[aq]title\[aq])
+\f[]
+.fi
+.PP
+Incorrect:
+.IP
+.nf
+\f[C]
+TITLE_RE\ =\ r\[aq]<title>([^<]+)</title>\[aq]
+#\ ...some\ lines\ of\ code...
+title\ =\ self._html_search_regex(TITLE_RE,\ webpage,\ \[aq]title\[aq])
+\f[]
+.fi
+.SS Collapse fallbacks
+.PP
+Multiple fallback values can quickly become unwieldy.
+Collapse multiple fallback values into a single expression via a list of
+patterns.
+.SS Example
+.PP
+Good:
+.IP
+.nf
+\f[C]
+description\ =\ self._html_search_meta(
+\ \ \ \ [\[aq]og:description\[aq],\ \[aq]description\[aq],\ \[aq]twitter:description\[aq]],
+\ \ \ \ webpage,\ \[aq]description\[aq],\ default=None)
+\f[]
+.fi
+.PP
+Unwieldy:
+.IP
+.nf
+\f[C]
+description\ =\ (
+\ \ \ \ self._og_search_description(webpage,\ default=None)
+\ \ \ \ or\ self._html_search_meta(\[aq]description\[aq],\ webpage,\ default=None)
+\ \ \ \ or\ self._html_search_meta(\[aq]twitter:description\[aq],\ webpage,\ default=None))
+\f[]
+.fi
+.PP
+Methods supporting list of patterns are: \f[C]_search_regex\f[],
+\f[C]_html_search_regex\f[], \f[C]_og_search_property\f[],
+\f[C]_html_search_meta\f[].
+.SS Trailing parentheses
+.PP
+Always move trailing parentheses after the last argument.
+.SS Example
+.PP
+Correct:
+.IP
+.nf
+\f[C]
+\ \ \ \ lambda\ x:\ x[\[aq]ResultSet\[aq]][\[aq]Result\[aq]][0][\[aq]VideoUrlSet\[aq]][\[aq]VideoUrl\[aq]],
+\ \ \ \ list)
+\f[]
+.fi
+.PP
+Incorrect:
+.IP
+.nf
+\f[C]
+\ \ \ \ lambda\ x:\ x[\[aq]ResultSet\[aq]][\[aq]Result\[aq]][0][\[aq]VideoUrlSet\[aq]][\[aq]VideoUrl\[aq]],
+\ \ \ \ list,
+)
+\f[]
+.fi

 .SS Use convenience conversion and parsing functions
 .PP
 Wrap all extracted numeric data into safe functions from
 .SS Use convenience conversion and parsing functions
 .PP
 Wrap all extracted numeric data into safe functions from