[LyX/master] Add != operator to FuncRequest and special value FuncRequest::prefix

[Jean-Marc Lasgouttes]

commit 46992201b71c3b20e9cdf640ce1b8d36ecaf48ac
Author: Jean-Marc Lasgouttes <lasgouttes at lyx.org>
Date:   Fri Dec 9 14:43:19 2022 +0100

    Add != operator to FuncRequest and special value FuncRequest::prefix
    
    Use this value (and `unknown' where relevant)
---
 src/FuncRequest.cpp           |    8 ++++++++
 src/FuncRequest.h             |    5 +++++
 src/KeyMap.cpp                |    3 +--
 src/frontends/qt/GuiPrefs.cpp |    3 ++-
 4 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/FuncRequest.cpp b/src/FuncRequest.cpp
index 25ea41a..1597027 100644
--- a/src/FuncRequest.cpp
+++ b/src/FuncRequest.cpp
@@ -28,6 +28,7 @@ namespace lyx {
 
 FuncRequest const FuncRequest::unknown(LFUN_UNKNOWN_ACTION);
 FuncRequest const FuncRequest::noaction(LFUN_NOACTION);
+FuncRequest const FuncRequest::prefix(LFUN_COMMAND_PREFIX);
 
 FuncRequest::FuncRequest(Origin o)
 	: origin_(o)
@@ -114,12 +115,19 @@ string FuncRequest::getLongArg(unsigned int i) const
 	return i < args.size() ? args[i] : string();
 }
 
+
 bool operator==(FuncRequest const & lhs, FuncRequest const & rhs)
 {
 	return lhs.action() == rhs.action() && lhs.argument() == rhs.argument();
 }
 
 
+bool operator!=(FuncRequest const & lhs, FuncRequest const & rhs)
+{
+	return !(lhs == rhs);
+}
+
+
 ostream & operator<<(ostream & os, FuncRequest const & cmd)
 {
 	return os
diff --git a/src/FuncRequest.h b/src/FuncRequest.h
index 52fb143..efbe425 100644
--- a/src/FuncRequest.h
+++ b/src/FuncRequest.h
@@ -99,6 +99,9 @@ public:
 	///
 	static FuncRequest const noaction;
 	///
+	static FuncRequest const prefix;
+
+	///
 	bool allowAsync() const { return allow_async_; }
 	///
 	void allowAsync(bool allow_async) { allow_async_ = allow_async; }
@@ -129,6 +132,8 @@ private:
 
 bool operator==(FuncRequest const & lhs, FuncRequest const & rhs);
 
+bool operator!=(FuncRequest const & lhs, FuncRequest const & rhs);
+
 std::ostream & operator<<(std::ostream &, FuncRequest const &);
 
 LyXErr & operator<<(LyXErr &, FuncRequest const &);
diff --git a/src/KeyMap.cpp b/src/KeyMap.cpp
index 1fb82c2..c530f5f 100644
--- a/src/KeyMap.cpp
+++ b/src/KeyMap.cpp
@@ -457,8 +457,7 @@ FuncRequest const & KeyMap::lookup(KeySymbol const &key,
 			if (cit->prefixes) {
 				// this is a prefix key - set new map
 				seq->curmap = cit->prefixes.get();
-				static const FuncRequest prefix(LFUN_COMMAND_PREFIX);
-				return prefix;
+				return FuncRequest::prefix;
 			} else {
 				// final key - reset map
 				seq->reset();
diff --git a/src/frontends/qt/GuiPrefs.cpp b/src/frontends/qt/GuiPrefs.cpp
index c72baee..46baffd 100644
--- a/src/frontends/qt/GuiPrefs.cpp
+++ b/src/frontends/qt/GuiPrefs.cpp
@@ -3359,9 +3359,10 @@ docstring makeCmdString(FuncRequest const & f)
 FuncRequest PrefShortcuts::currentBinding(KeySequence const & k)
 {
 	FuncRequest res = user_bind_.getBinding(k);
-	if (res.action() != LFUN_UNKNOWN_ACTION)
+	if (res != FuncRequest::unknown)
 		return res;
 	res = system_bind_.getBinding(k);
+
 	// Check if it is unbound. Note: user_unbind_ can only unbind one
 	// FuncRequest per key sequence.
 	if (user_unbind_.getBinding(k) == res)