bash completion: Show values for implicit args

So eg. `tageditor get [tab][tab]` also suggests specifying
field names directly instead of only via --fields.

CMakeLists.txt

@@ -127,7 +127,7 @@ set(META_APP_URL "https://github.com/${META_APP_AUTHOR}/${META_PROJECT_NAME}")
 set(META_APP_DESCRIPTION "Common C++ classes and routines used by my applications such as argument parser, IO and conversion utilities")
 set(META_VERSION_MAJOR 4)
 set(META_VERSION_MINOR 9)
-set(META_VERSION_PATCH 1)
+set(META_VERSION_PATCH 2)
 
 # find required 3rd party libraries
 include(3rdParty)

application/argumentparser.cpp

@@ -858,23 +858,47 @@ void ArgumentParser::printBashCompletion(int argc, const char *const *argv, unsi
     bool nextArgumentOrValue;
     if (lastDetectedArg && lastDetectedArg->isPresent()) {
         if ((nextArgumentOrValue = (currentWordIndex > lastDetectedArgIndex))) {
-            // parameter values of the last arg are possible completions
+            // define function to add parameter values of argument as possible completions
+            const auto addValueCompletionsForArg = [&relevantPreDefinedValues, &completeFiles, &completeDirs](const Argument *arg) {
+                if (arg->valueCompletionBehaviour() & ValueCompletionBehavior::PreDefinedValues) {
+                    relevantPreDefinedValues.push_back(arg);
+                }
+                if (!(arg->valueCompletionBehaviour() & ValueCompletionBehavior::FileSystemIfNoPreDefinedValues)
+                    || !arg->preDefinedCompletionValues()) {
+                    completeFiles = completeFiles || arg->valueCompletionBehaviour() & ValueCompletionBehavior::Files;
+                    completeDirs = completeDirs || arg->valueCompletionBehaviour() & ValueCompletionBehavior::Directories;
+                }
+            };
+
+            // detect number of specified values
             auto currentValueCount = lastDetectedArg->values(lastDetectedArg->occurrences() - 1).size();
+            // ignore values which are specified after the current word
             if (currentValueCount) {
-                currentValueCount -= (currentWordIndex - lastDetectedArgIndex);
-            }
-            if (lastDetectedArg->requiredValueCount() == static_cast<size_t>(-1) || (currentValueCount < lastDetectedArg->requiredValueCount())) {
-                if (lastDetectedArg->valueCompletionBehaviour() & ValueCompletionBehavior::PreDefinedValues) {
-                    relevantPreDefinedValues.push_back(lastDetectedArg);
+                const auto currentWordIndexRelativeToLastDetectedArg = currentWordIndex - lastDetectedArgIndex;
+                if (currentValueCount > currentWordIndexRelativeToLastDetectedArg) {
+                    currentValueCount -= currentWordIndexRelativeToLastDetectedArg;
+                } else {
+                    currentValueCount = 0;
                 }
-                if (!(lastDetectedArg->valueCompletionBehaviour() & ValueCompletionBehavior::FileSystemIfNoPreDefinedValues)
-                    || !lastDetectedArg->preDefinedCompletionValues()) {
-                    completeFiles = completeFiles || lastDetectedArg->valueCompletionBehaviour() & ValueCompletionBehavior::Files;
-                    completeDirs = completeDirs || lastDetectedArg->valueCompletionBehaviour() & ValueCompletionBehavior::Directories;
+            }
+
+            // add value completions for implicit child if there are no value specified and there are no values required by the
+            // last detected argument itself
+            if (!currentValueCount && !lastDetectedArg->requiredValueCount()) {
+                for (const Argument *child : lastDetectedArg->subArguments()) {
+                    if (child->isImplicit() && child->requiredValueCount()) {
+                        addValueCompletionsForArg(child);
+                        break;
+                    }
                 }
             }
 
-            if (lastDetectedArg->requiredValueCount() == static_cast<size_t>(-1)
+            // add value completions for last argument if there are further values required
+            if (lastDetectedArg->requiredValueCount() == Argument::varValueCount || (currentValueCount < lastDetectedArg->requiredValueCount())) {
+                addValueCompletionsForArg(lastDetectedArg);
+            }
+
+            if (lastDetectedArg->requiredValueCount() == Argument::varValueCount
                 || lastDetectedArg->values(lastDetectedArg->occurrences() - 1).size() >= lastDetectedArg->requiredValueCount()) {
                 // sub arguments of the last arg are possible completions
                 for (const Argument *subArg : lastDetectedArg->subArguments()) {

tests/argumentparsertests.cpp

@@ -429,7 +429,7 @@ void ArgumentParserTests::testBashCompletion()
     Argument valuesArg("values", '\0', "specifies the fields");
     valuesArg.setRequiredValueCount(-1);
     valuesArg.setPreDefinedCompletionValues("title album artist trackpos");
-    valuesArg.setImplicit(true);
+    valuesArg.setImplicit(false);
     valuesArg.setValueCompletionBehavior(ValueCompletionBehavior::PreDefinedValues | ValueCompletionBehavior::AppendEquationSign);
     Argument getArg("get", 'g', "gets tag values");
     getArg.setSubArguments({ &fieldsArg, &filesArg });
@@ -519,6 +519,15 @@ void ArgumentParserTests::testBashCompletion()
         cout.rdbuf(regularCoutBuffer);
         CPPUNIT_ASSERT_EQUAL("COMPREPLY=('album=' 'artist='  ); compopt -o nospace\n"s, buffer.str());
 
+        // pre-defined values for implicit argument
+        buffer.str(string());
+        cout.rdbuf(buffer.rdbuf());
+        parser.resetArgs();
+        reader.reset(argv3, argv3 + 1).read();
+        parser.printBashCompletion(1, argv3, 2, reader);
+        cout.rdbuf(regularCoutBuffer);
+        CPPUNIT_ASSERT_EQUAL("COMPREPLY=('title' 'album' 'artist' 'trackpos' '--fields' '--files' )\n"s, buffer.str());
+
         // file names
         string iniFilePath = TestUtilities::testFilePath("test.ini");
         iniFilePath.resize(iniFilePath.size() - 4);