all: add support for document attribute "last-update-label"

By default the last-update-label value set to "Last updated" and the
value is the document modification time.

If the label is suppressed with "!", no "Last updated" will be print
on the footer.

1 files changed, 30 insertions, 28 deletions

diff --git a/parser.go b/parser.go
index bc7da9e..fe6e0ff 100644
--- a/parser.go
+++ b/parser.go
@@ -178,34 +178,36 @@ const (
 	MetaNameGenerator   = `generator`
 	MetaNameKeywords    = `keywords`
 
-	metaNameAuthorInitials = `authorinitials`
-	metaNameDocTitle       = `doctitle`
-	metaNameEmail          = attrValueEmail
-	metaNameFirstName      = `firstname`
-	metaNameIDPrefix       = `idprefix`
-	metaNameIDSeparator    = `idseparator`
-	metaNameLastName       = `lastname`
-	metaNameMiddleName     = `middlename`
-	metaNameNoFooter       = `nofooter`
-	metaNameNoHeader       = `noheader`
-	metaNameNoHeaderFooter = `no-header-footer`
-	metaNameNoTitle        = `notitle`
-	metaNameRevDate        = `revdate`
-	metaNameRevNumber      = `revnumber`
-	metaNameRevRemark      = `revremark`
-	metaNameSectAnchors    = `sectanchors`
-	metaNameSectIDs        = `sectids`
-	metaNameSectLinks      = `sectlinks`
-	metaNameSectNumLevel   = `sectnumlevels`
-	metaNameSectNums       = `sectnums`
-	metaNameShowTitle      = `showtitle`
-	metaNameTOC            = `toc`
-	metaNameTOCLevels      = `toclevels`
-	metaNameTOCTitle       = `toc-title`
-	metaNameTableCaption   = `table-caption`
-	metaNameTitle          = attrNameTitle
-	metaNameTitleSeparator = `title-separator`
-	metaNameVersionLabel   = `version-label`
+	metaNameAuthorInitials  = `authorinitials`
+	metaNameDocTitle        = `doctitle`
+	metaNameEmail           = attrValueEmail
+	metaNameFirstName       = `firstname`
+	metaNameIDPrefix        = `idprefix`
+	metaNameIDSeparator     = `idseparator`
+	metaNameLastName        = `lastname`
+	metaNameLastUpdateLabel = `last-update-label`
+	metaNameLastUpdateValue = `last-update-value`
+	metaNameMiddleName      = `middlename`
+	metaNameNoFooter        = `nofooter`
+	metaNameNoHeader        = `noheader`
+	metaNameNoHeaderFooter  = `no-header-footer`
+	metaNameNoTitle         = `notitle`
+	metaNameRevDate         = `revdate`
+	metaNameRevNumber       = `revnumber`
+	metaNameRevRemark       = `revremark`
+	metaNameSectAnchors     = `sectanchors`
+	metaNameSectIDs         = `sectids`
+	metaNameSectLinks       = `sectlinks`
+	metaNameSectNumLevel    = `sectnumlevels`
+	metaNameSectNums        = `sectnums`
+	metaNameShowTitle       = `showtitle`
+	metaNameTOC             = `toc`
+	metaNameTOCLevels       = `toclevels`
+	metaNameTOCTitle        = `toc-title`
+	metaNameTableCaption    = `table-caption`
+	metaNameTitle           = attrNameTitle
+	metaNameTitleSeparator  = `title-separator`
+	metaNameVersionLabel    = `version-label`
 )
 
 // List of possible metadata value.