- Make all packages Expl3.

- Replace ifthen dependency with wrappers for Latex3 conditionals.
- Debug CrossRef and WrapBoxout.

Manual.cls

@@ -4,77 +4,87 @@
 	published by Prime Controls.
 }
 
-\RequirePackage{ifthen}
-
 % Option 'electronic': single side printing.
-\newboolean{isElectronic}
-\setboolean{isElectronic}{false}
+\bool_new:N \g_electronic_bool
+\bool_gset_false:N \g_electronic_bool
 
 \DeclareOption{electronic}{
-	\setboolean{isElectronic}{true}
+	\bool_gset_true:N \g_electronic_bool
 }
 
+\NewExpandableDocumentCommand{\IsElectronic}{}{\g_electronic_bool}
+
 % Option 'admin': turn on admin manual sections.
-\newboolean{isAdminManual}
-\setboolean{isAdminManual}{false}
+\bool_new:N \g_admin_bool
+\bool_gset_false:N \g_admin_bool
 
 \DeclareOption{admin}{
-	\setboolean{isAdminManual}{true}
+	\bool_gset_true:N \g_admin_bool
 }
 
+\NewExpandableDocumentCommand{\IsAdminManual}{}{\g_admin_bool}
+
 % Option 'darkmode': render as light text on dark background.
-\newboolean{isDarkMode}
-\setboolean{isDarkMode}{false}
+\bool_new:N \g_dark_mode_bool
+\bool_gset_false:N \g_dark_mode_bool
 
 \DeclareOption{darkmode}{
-	\setboolean{isDarkMode}{true}
+	\bool_gset_true:N \g_dark_mode_bool
 }
 
+\NewExpandableDocumentCommand{\IsDarkMode}{}{\g_dark_mode_bool}
+
 % Option 'draft': same as base book class, but with bigger overfull boxes.
-\newboolean{isDraft}
-\setboolean{isDraft}{false}
+\bool_new:N \g_draft_bool
+\bool_gset_false:N \g_draft_bool
 
 \DeclareOption{draft}{
-	\setboolean{isDraft}{true}
+	\bool_gset_true:N \g_draft_bool
 	\overfullrule = 1in
 }
 
-% Option 'admin': turn on admin manual sections.
-\newboolean{doRomanNumerals}
-\setboolean{doRomanNumerals}{false}
+\NewExpandableDocumentCommand{\IsDraft}{}{\g_draft_bool}
+
+% Option 'roman': render Part numbers as Roman numerals.
+\bool_new:N \g_roman_bool
+\bool_gset_false:N \g_roman_bool
 
 \DeclareOption{roman}{
-	\setboolean{doRomanNumerals}{true}
+	\bool_gset_true:N \g_roman_bool
 }
 
+\NewExpandableDocumentCommand{\DoRomanNumerals}{}{\g_roman_bool}
+
+% Option 'labels': show Part and Chapter labels in the header.
+\bool_new:N \g_label_bool
+\bool_gset_false:N \g_label_bool
+
+\DeclareOption{labels}{
+	\bool_gset_true:N \g_label_bool
+}
+
+\NewExpandableDocumentCommand{\ShowLabels}{}{\g_label_bool}
+
 \DeclareOption*{\PassOptionsToClass{\CurrentOption}{book}}
 
 \ProcessOptions\relax
 
-\ifthenelse{\boolean{isElectronic}}{
-	\ifthenelse{\boolean{isDraft}}{
+\bool_if:NTF \g_electronic_bool {
+	\bool_if:NTF \g_draft_bool {
 		\LoadClass[draft,oneside]{book}
-	}{
+	} {
 		\LoadClass[oneside]{book}
 	}
-}{
-	\ifthenelse{\boolean{isDraft}}{
+} {
+	\bool_if:NTF \g_draft_bool {
 		\LoadClass[draft]{book}
-	}{
+	} {
 		\LoadClass{book}
 	}
 }
 
 \input{PrimeTeX/commonincludes.def}
 
-\NewDocumentCommand{\IfAdminManual}{+m +m}{
-	\ifthenelse{\boolean{isAdminManual}}{#1}{#2}
-}
-
-\NewDocumentCommand{\IfElectronic}{+m +m}{
-	\ifthenelse{\boolean{isElectronic}}{#1}{#2}
-}
-
 \NewDocumentCommand{\rem}{+m}{}
 
 \str_new:N \l_IncludeOnly_chapters_str