I... think it's done? That was suspiciously easy.

lib/flags.cc

@@ -49,10 +49,12 @@ void FlagGroup::parseFlags(int argc, const char* argv[])
 
         for (Flag* flag : group->_flags)
         {
-            const auto& name = flag->name();
-            if (flags_by_name.find(name) != flags_by_name.end())
-                Error() << "two flags use the name '" << name << "'";
-            flags_by_name[name] = flag;
+            for (const auto& name : flag->names())
+            {
+                if (flags_by_name.find(name) != flags_by_name.end())
+                    Error() << "two flags use the name '" << name << "'";
+                flags_by_name[name] = flag;
+            }
 
             all_flags.push_back(flag);
         }
@@ -60,6 +62,7 @@ void FlagGroup::parseFlags(int argc, const char* argv[])
         group->_initialised = true;
     };
     recurse(this);
+    recurse(&helpGroup);
 
     /* Now actually parse them. */
 

lib/fluxsource/fluxsource.h

@@ -1,6 +1,10 @@
 #ifndef FLUXSOURCE_H
 #define FLUXSOURCE_H
 
+#include "flags.h"
+
+extern FlagGroup hardwareFluxSourceFlags;
+
 class Fluxmap;
 class DataSpec;
 

lib/reader.cc

@@ -16,7 +16,7 @@
 #include "track.h"
 #include "fmt/format.h"
 
-FlagGroup readerFlags;
+FlagGroup readerFlags { &hardwareFluxSourceFlags, &fluxmapReaderFlags };
 
 static DataSpecFlag source(
     { "--source", "-s" },

lib/reader.h

@@ -1,11 +1,15 @@
 #ifndef READER_H
 #define READER_H
 
+#include "flags.h"
+
 class Fluxmap;
 class FluxSource;
 class AbstractDecoder;
 class Track;
 
+extern FlagGroup readerFlags;
+
 extern void setReaderDefaultSource(const std::string& source);
 extern void setReaderRevolutions(int revolutions);
 

lib/writer.cc

@@ -10,7 +10,7 @@
 #include "fluxsink.h"
 #include "fmt/format.h"
 
-FlagGroup writerFlags;
+FlagGroup writerFlags { &hardwareFluxSourceFlags };
 
 static DataSpecFlag dest(
     { "--dest", "-d" },

lib/writer.h

@@ -1,6 +1,10 @@
 #ifndef WRITER_H
 #define WRITER_H
 
+#include "flags.h"
+
+extern FlagGroup writerFlags;
+
 class Fluxmap;
 
 extern void setWriterDefaultDest(const std::string& dest);

src/fe-readadfs.cc

@@ -10,7 +10,7 @@
 #include "ibm.h"
 #include <fmt/format.h>
 
-FlagGroup flags;
+FlagGroup flags { &readerFlags };
 
 static StringFlag outputFilename(
     { "--output", "-o" },

src/fe-readaeslanier.cc

@@ -10,7 +10,7 @@
 #include "aeslanier.h"
 #include <fmt/format.h>
 
-FlagGroup flags;
+FlagGroup flags { &readerFlags };
 
 static StringFlag outputFilename(
     { "--output", "-o" },

src/fe-readamiga.cc

@@ -11,7 +11,7 @@
 #include <fmt/format.h>
 #include <fstream>
 
-FlagGroup flags;
+FlagGroup flags { &readerFlags };
 
 static StringFlag outputFilename(
     { "--output", "-o" },

src/fe-readampro.cc

@@ -10,7 +10,7 @@
 #include "ibm.h"
 #include <fmt/format.h>
 
-FlagGroup flags;
+FlagGroup flags { &readerFlags };
 
 static StringFlag outputFilename(
     { "--output", "-o" },

src/fe-readapple2.cc

@@ -11,7 +11,7 @@
 #include <fmt/format.h>
 #include <fstream>
 
-FlagGroup flags;
+FlagGroup flags { &readerFlags };
 
 static StringFlag outputFilename(
     { "--output", "-o" },

src/fe-readbrother.cc

@@ -11,7 +11,7 @@
 #include <fmt/format.h>
 #include <fstream>
 
-FlagGroup flags;
+FlagGroup flags { &readerFlags };
 
 static StringFlag outputFilename(
     { "--output", "-o" },

src/fe-readc64.cc

@@ -11,7 +11,7 @@
 #include <fmt/format.h>
 #include <fstream>
 
-FlagGroup flags;
+FlagGroup flags { &readerFlags };
 
 static StringFlag outputFilename(
     { "--output", "-o" },

src/fe-readdfs.cc

@@ -10,7 +10,7 @@
 #include "ibm.h"
 #include <fmt/format.h>
 
-FlagGroup flags;
+FlagGroup flags { &readerFlags };
 
 static StringFlag outputFilename(
     { "--output", "-o" },

src/fe-readf85.cc

@@ -11,7 +11,7 @@
 #include <fmt/format.h>
 #include <fstream>
 
-FlagGroup flags;
+FlagGroup flags { &readerFlags };
 
 static StringFlag outputFilename(
     { "--output", "-o" },

src/fe-readfb100.cc

@@ -10,7 +10,7 @@
 #include "fb100.h"
 #include <fmt/format.h>
 
-FlagGroup flags;
+FlagGroup flags { &readerFlags };
 
 static StringFlag outputFilename(
     { "--output", "-o" },

src/fe-readibm.cc

@@ -10,7 +10,7 @@
 #include "ibm.h"
 #include <fmt/format.h>
 
-FlagGroup flags;
+FlagGroup flags { &readerFlags };
 
 static StringFlag outputFilename(
     { "--output", "-o" },

src/fe-readmac.cc

@@ -11,7 +11,7 @@
 #include <fmt/format.h>
 #include <fstream>
 
-FlagGroup flags;
+FlagGroup flags { &readerFlags };
 
 static StringFlag outputFilename(
     { "--output", "-o" },

src/fe-readvictor9k.cc

@@ -11,7 +11,7 @@
 #include <fmt/format.h>
 #include <fstream>
 
-FlagGroup flags;
+FlagGroup flags { &readerFlags };
 
 static StringFlag outputFilename(
     { "--output", "-o" },

src/fe-readzilogmcz.cc

@@ -10,7 +10,7 @@
 #include "zilogmcz.h"
 #include <fmt/format.h>
 
-FlagGroup flags;
+FlagGroup flags { &readerFlags };
 
 static StringFlag outputFilename(
     { "--output", "-o" },

src/fe-writebrother.cc

@@ -11,7 +11,7 @@
 #include <fstream>
 #include <ctype.h>
 
-FlagGroup flags;
+FlagGroup flags { &writerFlags };
 
 static StringFlag inputFilename(
     { "--input", "-i" },

src/fe-writeflux.cc

@@ -10,7 +10,7 @@
 #include <fstream>
 #include <ctype.h>
 
-FlagGroup flags;
+FlagGroup flags { &writerFlags };
 
 int main(int argc, const char* argv[])
 {

src/fe-writetestpattern.cc

@@ -8,7 +8,7 @@
 #include <fstream>
 #include <ctype.h>
 
-FlagGroup flags;
+FlagGroup flags { &writerFlags };
 
 static DoubleFlag interval(
 	{ "--interval" },