Simplified filename date fallback configuration.

Removed useFilenameDateAsFallback option and instead check to see if filenameDateFallbackPattern is set. As a result, filenameDateFallbackPattern now defaults to Nil.

Added a reference example to the docs to ease copy/paste configuration for a popular YYYY-MM-DD filename format.

docs/content/content/front-matter.md

@@ -1,7 +1,7 @@
 ---
 aliases:
 - /doc/front-matter/
-lastmod: 2017-04-09
+lastmod: 2017-06-29
 date: 2013-07-01
 menu:
   main:
@@ -118,4 +118,11 @@ It's possible to set some options for Markdown rendering in the page's front mat
 See [Configuration]({{< ref "overview/configuration.md#configure-blackfriday-rendering" >}}) for more.
 
 ## Fallback date variable from filenames
-If you're migrating content to Hugo, you may have content with dates in the filename. For example `2017-01-31-myblog.md`.  You can optionally enable the `useFilenameDateAsFallback` configuration option. This will attempt to parse the datestamp in the filename and use it as a fallback to providing a date variable in the frontmatter.
+If you're migrating content to Hugo, you may have content with dates in the filename. For example `2017-01-31-myblog.md`.  You can optionally enable the `filenameDateFallbackPattern` and `filenameDateFallbackFormat` configuration options. These will allow you to fallback on datestamps provided in the filename in place of a date value in the front matter.
+
+As an example, for posts following a YYY-MM-DD-posttitle.md naming convention, you can use:
+
+```
+filenameDateFallbackPattern: "(?P<year>\\d{4})\\-(?P<month>\\d{2})\\-(?P<day>\\d{2})"
+filenameDateFallbackFormat: "2006-01-02"
+```

docs/content/overview/configuration.md

@@ -139,9 +139,9 @@ along with their current, default values:
     enableEmoji:				false
     # Show a placeholder instead of the default value or an empty string if a translation is missing
     enableMissingTranslationPlaceholders: false
-    # Regex to use for dates in filenames. Only used with `useFilenameDateAsFallback`
+    # Regex to use for dates in filenames.
     filenameDateFallbackPattern: "(?P<year>\\d{4})\\-(?P<month>\\d{2})\\-(?P<day>\\d{2})"
-    # Time format for custom dates in filenames. Only used with `useFilenameDateAsFallback` and must match `filenameDateFallbackPattern`
+    # Time format for custom dates in filenames. Must match `filenameDateFallbackPattern`
     filenameDateFallbackFormat: "2006-01-02"
     footnoteAnchorPrefix:       ""
     footnoteReturnLinkContents: ""
@@ -191,8 +191,6 @@ along with their current, default values:
     title:                      ""
     # if true, use /filename.html instead of /filename/
     uglyURLs:                   false
-    #if true, use dates in filenames e.g. 2017-01-31-mypostname.md
-    useFilenameDateAsFallback:  false
     # Do not make the url/path to lowercase
     disablePathToLower:         false
     # if true, auto-detect Chinese/Japanese/Korean Languages in the content. (.Summary and .WordCount can work properly in CJKLanguage)

hugolib/config.go

@@ -108,8 +108,7 @@ func loadDefaultSettingsFor(v *viper.Viper) {
 	v.SetDefault("enableEmoji", false)
 	v.SetDefault("pygmentsCodeFencesGuessSyntax", false)
 	v.SetDefault("useModTimeAsFallback", false)
-	v.SetDefault("useFilenameDateAsFallback", false)
-	v.SetDefault("filenameDateFallbackPattern", "(?P<year>\\d{4})\\-(?P<month>\\d{2})\\-(?P<day>\\d{2})")
+	v.SetDefault("filenameDateFallbackPattern", nil)
 	v.SetDefault("filenameDateFallbackFormat", "2006-01-02")
 	v.SetDefault("defaultContentLanguage", "en")
 	v.SetDefault("defaultContentLanguageInSubdir", false)

hugolib/page.go

@@ -1021,7 +1021,7 @@ func (p *Page) update(f interface{}) error {
 			p.Date = fi.ModTime()
 			p.Params["date"] = p.Date
 		}
-	} else if p.Date.IsZero() && p.s.Cfg.GetBool("useFilenameDateAsFallback") {
+	} else if p.Date.IsZero() && p.s.Cfg.GetString("filenameDateFallbackPattern") != "" {
 		dateExp := regexp.MustCompile(p.s.Cfg.GetString("filenameDateFallbackPattern"))
 		dateString := dateExp.FindString(p.File.Path())
 		filenameDate, err := time.Parse(p.s.Cfg.GetString("filenameDateFallbackFormat"), dateString)