add overloads and tests, and improve help generation in general

2 files changed, 56 insertions, 21 deletions

diff --git a/args.hxx b/args.hxx
index 4afb905..d5165f6 100644
--- a/args.hxx
+++ b/args.hxx
@@ -679,14 +679,31 @@ namespace args
         public:
             struct HelpParams
             {
+                /** The width of the help menu
+                 */
                 unsigned int width = 80;
+                /** The indent of the program line
+                 */
                 unsigned int progindent = 2;
-                unsigned int progtailindent = 2;
+                /** The indent of the program trailing lines for long parameters
+                 */
+                unsigned int progtailindent = 4;
+                /** The indent of the description and epilogs
+                 */
                 unsigned int descriptionindent = 4;
-                unsigned int flagindent = 4;
-                unsigned int eachgroupindent = 2;
+                /** The indent of the flags
+                 */
+                unsigned int flagindent = 6;
+                /** The indent of the flag descriptions
+                 */
                 unsigned int helpindent = 25;
-                unsigned int gutter = 25;
+                /** The additional indent each group adds
+                 */
+                unsigned int eachgroupindent = 2;
+
+                /** The minimum gutter between each flag and its help
+                 */
+                unsigned int gutter = 1;
             } helpParams;
             ArgumentParser(const std::string &description, const std::string &epilog = std::string()) :
                 Group("arguments", Group::Validators::AllChildGroups),
@@ -750,10 +767,6 @@ namespace args
              */
             void LongSeparator(const std::string &longseparator)
             {
-                if (longseparator.empty())
-                {
-                    throw ParseError("The long separator may not be empty");
-                }
                 this->longseparator = longseparator;
             }
 
@@ -766,24 +779,15 @@ namespace args
             void Terminator(const std::string &terminator)
             { this->terminator = terminator; }
 
-            /** Generate a help menu as a string.
-             *
-             * \param width the width of the terminal
-             * \param progindent the indent of the program name line
-             * \param descriptionindent the indent of the description and epilog lines
-             * \param flagindent the indent of the flags themselves
-             * \param helpindent the indent of the flag help texts
-             * \param gutter the required minimum spacing between the flag text and the flag help
-             * \return the help text as a single string
+            /** Pass the help menu into an ostream
              */
-            std::string Help() const
+            void Help(std::ostream &help) const
             {
                 bool hasoptions = false;
                 bool hasarguments = false;
 
                 const std::vector<std::string> description(Wrap(this->description, helpParams.width - helpParams.descriptionindent));
                 const std::vector<std::string> epilog(Wrap(this->epilog, helpParams.width - helpParams.descriptionindent));
-                std::ostringstream help;
                 std::ostringstream prognameline;
                 prognameline << prog;
                 if (HasFlag())
@@ -805,7 +809,7 @@ namespace args
                 }
                 for (; progit != std::end(proglines); ++progit)
                 {
-                    help << std::string(helpParams.progindent + 4, ' ') << *progit << '\n';
+                    help << std::string(helpParams.progtailindent, ' ') << *progit << '\n';
                 }
 
                 help << '\n';
@@ -849,6 +853,16 @@ namespace args
                 {
                     help << std::string(helpParams.descriptionindent, ' ') << line << "\n";
                 }
+            }
+
+            /** Generate a help menu as a string.
+             *
+             * \return the help text as a single string
+             */
+            std::string Help() const
+            {
+                std::ostringstream help;
+                Help(help);
                 return help.str();
             }
 
@@ -876,7 +890,7 @@ namespace args
                     {
                         const std::string argchunk(chunk.substr(longprefix.size()));
                         // Try to separate it, in case of a separator:
-                        const auto separator = argchunk.find(longseparator);
+                        const auto separator = longseparator.empty() ? argchunk.npos : argchunk.find(longseparator);
                         const std::string arg = (separator != argchunk.npos ?
                             std::string(argchunk, 0, separator)
                             : argchunk);
@@ -997,6 +1011,12 @@ namespace args
             }
     };
 
+    std::ostream &operator<<(std::ostream &os, ArgumentParser &parser)
+    {
+        parser.Help(os);
+        return os;
+    }
+
     /** Boolean argument matcher
      */
     class Flag : public FlagBase
diff --git a/test.cxx b/test.cxx
index c39e000..3ad5533 100644
--- a/test.cxx
+++ b/test.cxx
@@ -245,3 +245,18 @@ TEST_CASE("Custom parser prefixes (Some Windows styles)", "[args]")
     REQUIRE(input.value == "/dev/null");
     REQUIRE_FALSE(output);
 }
+
+TEST_CASE("Help menu can be grabbed as a string, passed into a stream, or by using the overloaded stream operator", "[args]")
+{
+    std::ostream null(nullptr);
+    args::ArgumentParser parser("This command likes to break your disks");
+    args::HelpFlag help(parser, "HELP", "Show this help menu.", args::Matcher({"help"}));
+    args::ArgFlag<long> bs(parser, "BYTES", "Block size", args::Matcher({"bs"}), 512);
+    args::ArgFlag<long> skip(parser, "BYTES", "Bytes to skip", args::Matcher({"skip"}), 0);
+    args::ArgFlag<std::string> input(parser, "BLOCK SIZE", "Block size", args::Matcher({"if"}));
+    args::ArgFlag<std::string> output(parser, "BLOCK SIZE", "Block size", args::Matcher({"of"}));
+    parser.ParseArgs(std::vector<std::string>{"--skip=8", "--if=/dev/null"});
+    null << parser.Help();
+    parser.Help(null);
+    null << parser;
+}