Rewrite Float commands in Latex3 and move them to new Floats package.

packages/Boxout.sty

@@ -62,25 +62,31 @@
 	}%
 }{}
 
+\ExplSyntaxOn
 \NewDocumentEnvironment{BigBoxout}{
 	% #1: Overhang, passed to BigFloat argument #1.
-	O{\bigfloatoverhang}
+	O{\c_BigFloat_overhang_dim}
 	% #2: Float placement, passed to BigFloat argument #2.
-	O{htpb}
+	O{h,t,p,b}
 	% #3: Offset ratio, passed to BigFloat argument #3.
-	O{\bigfloatoffsetratio}
+	O{\c_BigFloat_offset_fp}
 	% #4: Label, passed to Boxout argument #1.
 	>{\TrimSpaces}m
-	% #5: Tabularray colpec, passed to Boxout argument #2.
+	% #5: Tabularray colspec, passed to Boxout argument #2.
 	O{X[l,h]}
 	% #6: Caption, passed to Boxout argument #3.
 	m
 	% #7: [Ww] for warning box, if present passed to Boxout argument #4.
 	o
-	% #5: Body, passed to Boxout.
+	% #8: Body, passed to Boxout.
 	+b
 }{
-	\begin{BigFloat}[generic][#1][#2][#3]%
+	\begin{BigFloat}[
+		type		= generic,
+		overhang	= #1,
+		placement	= {#2},
+		offset		= #3,
+	]%
 		\IfNoValueTF{#7}{%
 			\begin{Boxout}{#4}[#5]{#6}%
 				#8%
@@ -92,6 +98,7 @@
 		}%
 	\end{BigFloat}%
 }{}
+\ExplSyntaxOff
 
 \NewDocumentEnvironment{WrapBoxout}{
 	% position [l,r,i,o]