add convenience function for printing a missing arguments error message

doc/src/Developer_utils.rst

@@ -211,6 +211,9 @@ Convenience functions
 .. doxygenfunction:: logmesg(LAMMPS *lmp, const std::string &mesg)
    :project: progguide
 
+.. doxygenfunction:: missing_cmd_args
+   :project: progguide
+
 .. doxygenfunction:: flush_buffers(LAMMPS *lmp)
    :project: progguide
 

src/utils.cpp

@@ -22,8 +22,8 @@
 #include "memory.h"
 #include "modify.h"
 #include "text_file_reader.h"
-#include "update.h"
 #include "universe.h"
+#include "update.h"
 
 #include <cctype>
 #include <cerrno>
@@ -120,6 +120,12 @@ std::string utils::strfind(const std::string &text, const std::string &pattern)
     return "";
 }
 
+void utils::missing_cmd_args(const std::string &file, int line, const std::string &cmd,
+                             Error *error)
+{
+  if (error) error->all(file, line, "Illegal {} command: missing argument(s)", cmd);
+}
+
 /* specialization for the case of just a single string argument */
 
 void utils::logmesg(LAMMPS *lmp, const std::string &mesg)
@@ -141,7 +147,7 @@ void utils::flush_buffers(LAMMPS *lmp)
 {
   if (lmp->screen) fflush(lmp->screen);
   if (lmp->logfile) fflush(lmp->logfile);
-  if (lmp->universe->uscreen)  fflush(lmp->universe->uscreen);
+  if (lmp->universe->uscreen) fflush(lmp->universe->uscreen);
   if (lmp->universe->ulogfile) fflush(lmp->universe->ulogfile);
 }
 
@@ -566,14 +572,14 @@ void utils::bounds(const char *file, int line, const std::string &str,
       error->all(file, line, fmt::format("Invalid range string: {}", str));
 
     if (nlo < nmin)
-      error->all(file, line, fmt::format("Numeric index {} is out of bounds "
-                             "({}-{})", nlo, nmin, nmax));
+      error->all(file, line, fmt::format("Numeric index {} is out of bounds ({}-{})",
+                                         nlo, nmin, nmax));
     else if (nhi > nmax)
-      error->all(file, line, fmt::format("Numeric index {} is out of bounds "
-                             "({}-{})", nhi, nmin, nmax));
+      error->all(file, line, fmt::format("Numeric index {} is out of bounds ({}-{})",
+                                         nhi, nmin, nmax));
     else if (nlo > nhi)
-      error->all(file, line, fmt::format("Numeric index {} is out of bounds "
-                             "({}-{})", nlo, nmin, nhi));
+      error->all(file, line, fmt::format("Numeric index {} is out of bounds ({}-{})",
+                                         nlo, nmin, nhi));
   }
 }
 
@@ -805,7 +811,7 @@ std::string utils::star_subst(const std::string &name, bigint step, int pad)
   auto star = name.find('*');
   if (star == std::string::npos) return name;
 
-  return fmt::format("{}{:0{}}{}",name.substr(0,star),step,pad,name.substr(star+1));
+  return fmt::format("{}{:0{}}{}", name.substr(0, star), step, pad, name.substr(star + 1));
 }
 
 /* ----------------------------------------------------------------------

src/utils.h

@@ -21,7 +21,7 @@
 
 #include <mpi.h>
 
-#include <vector> // IWYU pragma: export
+#include <vector>    // IWYU pragma: export
 
 namespace LAMMPS_NS {
 
@@ -47,6 +47,18 @@ namespace utils {
 
   std::string strfind(const std::string &text, const std::string &pattern);
 
+  /*! Print error message about missing arguments for command
+   *
+   * This function simplifies the repetitive reporting missing arguments to a command.
+   *
+   *  \param file     name of source file for error message
+   *  \param line     line number in source file for error message
+   *  \param cmd      name of the failing command
+   *  \param error    pointer to Error class instance (for abort) or nullptr */
+
+  [[noreturn]] void missing_cmd_args(const std::string &file, int line, const std::string &cmd,
+                                     Error *error);
+
   /* Internal function handling the argument list for logmesg(). */
 
   void fmtargs_logmesg(LAMMPS *lmp, fmt::string_view format, fmt::format_args args);