Support command-line options with optional value

rvs/include/rvscli.h

@@ -1,6 +1,6 @@
 /********************************************************************************
  *
- * Copyright (c) 2018-2022 Advanced Micro Devices, Inc. All rights reserved.
+ * Copyright (c) 2018-2024 Advanced Micro Devices, Inc. All rights reserved.
  *
  * MIT LICENSE:
  * Permission is hereby granted, free of charge, to any person obtaining a copy of
@@ -60,14 +60,15 @@ class cli {
  * @brief Possible continuation types
  *
  * Defines possible type for the next token:
- * |value    |meaning
- * |---------|-------------------------
- * |eof      |end of input
- * |value    |value expected (must be different then command strings defined throuth grammar)
- * |command  |command string as defined in grammar
+ * |value          |meaning
+ * |---------------|-------------------------
+ * |eof            |end of input
+ * |value          |value always expected (must be different then command strings defined through grammar)
+ * |optionalvalue  |value not always expected (must be different then command strings defined through grammar)
+ * |command        |command string as defined in grammar
  *
  */
-  typedef enum {eof, value, command} econtext;
+  typedef enum {eof, value, optionalvalue, command} econtext;
 
   /**
  * @class optbase
@@ -100,6 +101,7 @@ class cli {
   const char*  get_token();
   bool  try_command(const std::string& token);
   bool  try_value(const std::string& token);
+  bool  try_optionalvalue(const std::string& token);
   bool  emit_option(void);
   void  init_grammar(void);
   void  extract_path(void);

rvs/src/rvscli.cpp

@@ -151,7 +151,7 @@ void rvs::cli::init_grammar() {
   grammar.insert(gpair("-i", sp));
   grammar.insert(gpair("--indexes", sp));
 
-  sp = std::make_shared<optbase>("-j", command);
+  sp = std::make_shared<optbase>("-j", command, optionalvalue);
   grammar.insert(gpair("-j", sp));
   grammar.insert(gpair("--json", sp));
 
@@ -224,6 +224,10 @@ int rvs::cli::parse(int Argc, char** Argv) {
         }
         break;
 
+      case econtext::optionalvalue:
+        token_done = try_optionalvalue(token);
+        break;
+
       case econtext::eof:
         if (token == "") {
           emit_option();
@@ -344,3 +348,30 @@ bool rvs::cli::try_value(const std::string& token) {
   return true;
 }
 
+/**
+ * @brief Try interpreting given token as a value if present following previous command line option.
+ *
+ * If successful, stores current token in a buffer as value
+ *
+ * @param token token being processed
+ * @return true if successful, false otherwise
+ *
+ */
+bool rvs::cli::try_optionalvalue(const std::string& token) {
+
+  if (token == "")
+    return true;
+
+  //  should not be one of command line options
+  auto it = grammar.find(token);
+  if (it != grammar.end())
+    return false;
+
+  // token is value for previous command
+  current_value = token;
+
+  // emit previous option-value pair:
+  emit_option();
+
+  return true;
+}