Merge pull request #465 from Hind-M/magics_help_message

Add custom `help` for magic commands
jupyter-xeus · Dec 5, 2022 · 79d2bb8 · 79d2bb8
2 parents 516aa7e + 71b7b3a
commit 79d2bb8
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Showing 5 changed files with 38 additions and 5 deletions.
diff --git a/include/xeus-cling/xmanager.hpp b/include/xeus-cling/xmanager.hpp
@@ -95,7 +95,8 @@ namespace xcpp
         {
             if (cell.empty())
             {
-                std::cerr << "UsageError: %%" << magic_name << " is a cell magic, but the cell body is empty.";
+                std::cerr << "UsageError: %%" << magic_name << " is a cell magic, but the cell body is empty." << std::endl;
+                std::cerr << "If you only intend to display %%" << magic_name << " help, please use a double line break to fill in the cell body.";
                 if (contains(magic_name, xmagic_type::line))
                 {
                     std::cerr << " Did you mean the line magic %" << magic_name << " (single %)?";

diff --git a/include/xeus-cling/xoptions.hpp b/include/xeus-cling/xoptions.hpp
@@ -14,6 +14,8 @@
 
 #include <argparse/argparse.hpp>
 
+#include "xeus-cling/xeus_cling_config.hpp"
+
 namespace xcpp
 {
     struct argparser : public argparse::ArgumentParser

diff --git a/src/xmagics/executable.cpp b/src/xmagics/executable.cpp
@@ -44,14 +44,24 @@ namespace xcpp
 {
     argparser executable::get_options()
     {
-        argparser argpars("executable");
+        argparser argpars("executable", XEUS_CLING_VERSION, argparse::default_arguments::none);
         argpars.add_description("write executable");
         argpars.add_argument("filename")
             .help("filename")
             .required();
         argpars.add_argument("options")
             .help("options")
             .default_value<std::vector<std::string>>({ "" });
+        // Add custom help (does not call `exit` avoiding to restart the kernel)
+        argpars.add_argument("-h", "--help")
+            .action([&](const std::string & /*unused*/)
+            {
+                std::cout << argpars.help().str();
+            })
+            .default_value(false)
+            .help("shows help message")
+            .implicit_value(true)
+            .nargs(0);
         return argpars;
     }
 

diff --git a/src/xmagics/execution.cpp b/src/xmagics/execution.cpp
@@ -35,7 +35,7 @@ namespace xcpp
 
     argparser timeit::get_options()
     {
-        argparser argpars("timeit");
+        argparser argpars("timeit", XEUS_CLING_VERSION, argparse::default_arguments::none);
         argpars.add_description("Time execution of a C++ statement or expression");
         argpars.add_argument("-n", "--number")
             .help("execute the given statement n times in a loop. If this value is not given, a fitting value is chosen")
@@ -52,6 +52,16 @@ namespace xcpp
         argpars.add_argument("expression")
             .help("expression to be evaluated")
             .remaining();
+        // Add custom help (does not call `exit` avoiding to restart the kernel)
+        argpars.add_argument("-h", "--help")
+            .action([&](const std::string & /*unused*/)
+            {
+                std::cout << argpars.help().str();
+            })
+            .default_value(false)
+            .help("shows help message")
+            .implicit_value(true)
+            .nargs(0);
         return argpars;
     }
 
@@ -112,7 +122,7 @@ namespace xcpp
         }
         catch (std::logic_error& e)
         {
-            if (trim(cell).empty())
+            if (trim(cell).empty() && (argpars["-h"] == false))
             {
                 std::cerr << "No expression given to evaluate" << std::endl;
             }

diff --git a/src/xmagics/os.cpp b/src/xmagics/os.cpp
@@ -22,7 +22,7 @@ namespace xcpp
 {
     argparser writefile::get_options()
     {
-        argparser argpars("file");
+        argparser argpars("file", XEUS_CLING_VERSION, argparse::default_arguments::none);
         argpars.add_description("write file");
         argpars.add_argument("-a", "--append")
             .help("append")
@@ -31,6 +31,16 @@ namespace xcpp
         argpars.add_argument("filename")
             .help("filename")
             .required();
+        // Add custom help (does not call `exit` avoiding to restart the kernel)
+        argpars.add_argument("-h", "--help")
+            .action([&](const std::string & /*unused*/)
+            {
+                std::cout << argpars.help().str();
+            })
+            .default_value(false)
+            .help("shows help message")
+            .implicit_value(true)
+            .nargs(0);
         return argpars;
     }