backporting tex2lyx: the support for \date{} in the preamble

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/branches/BRANCH_2_0_X@40054 a592a061-630c-0410-9148-cb99ea01b6c8

src/tex2lyx/TODO.txt

@@ -55,6 +55,7 @@ Format LaTeX feature                        LyX feature
 368    glue lengths                         InsetHSpace
 369    author id                            \author
 370    \date{}                              \suppress_date
+                                            (partly supported, see bug #7844)
 371    automatic mhchem loading             \use_mhchem
 375    \includeonly                         \{begin,end}_includeonly
 376    update .aux of unincluded children   \maintain_unincluded_children

src/tex2lyx/preamble.cpp

@@ -914,6 +914,14 @@ void parse_preamble(Parser & p, ostream & os,
 		else if (t.cs() == "pagestyle")
 			h_paperpagestyle = p.verbatim_item();
 
+		else if (t.cs() == "date") {
+			string argument = p.getArg('{', '}');
+			if (argument.empty())
+				h_suppress_date = "true";
+			else
+				h_preamble << t.asInput() << '{' << argument << '}';
+		}
+
 		else if (t.cs() == "color") {
 			string argument = p.getArg('{', '}');
 			// check the case that a standard color is used
@@ -1254,7 +1262,10 @@ void parse_preamble(Parser & p, ostream & os,
 			string const arg1 = p.verbatim_item();
 			string const arg2 = p.verbatim_item();
 			string const arg3 = p.verbatim_item();
-			if (!in_lyx_preamble) {
+			// test case \@ifundefined{date}{}{\date{}}
+			if (arg1 == "date" && arg2.empty() && arg3 == "\\date{}")
+				h_suppress_date = "true";
+			else if (!in_lyx_preamble) {
 				h_preamble << t.asInput()
 				           << '{' << arg1 << '}'
 				           << '{' << arg2 << '}'

status.20x

@@ -61,6 +61,8 @@ What's new
 
   * Rotated floats (sidewaysfigure, sidewaystable).
 
+  * Command \date{} in the preamble to suppress the date output.
+
 
 * USER INTERFACE