[cli] Improve error messages.

src/CLI/CLI.cs

@@ -94,7 +94,7 @@ namespace CppSharp
             if (Directory.Exists(dir))
                 options.IncludeDirs.Add(dir);
             else
-                messages.Add(string.Format("Directory {0} doesn't exist. Not adding as include directory.", dir));
+                messages.Add(string.Format("Directory '{0}' doesn't exist. Ignoring as include directory.", dir));
         }
 
         static void HandleOutputArg(string arg, List<string> messages)
@@ -138,12 +138,12 @@ namespace CppSharp
                     options.HeaderFiles.Add(args);
                 else
                 {
-                    messages.Add(string.Format("File {0} doesn't exist. Not adding to the list of files to generate bindings from.", args));
+                    messages.Add(string.Format("File '{0}' could not be found.", args));
                 }
             }
-            catch(Exception)
+            catch(Exception ex)
             {
-                messages.Add(string.Format("Error while looking for files inside path {0}. Ignoring.", args));
+                messages.Add(string.Format("Error while looking for files inside path '{0}'. Ignoring.", args));
             }
         }
 
@@ -182,7 +182,7 @@ namespace CppSharp
             }
             catch (Exception)
             {
-                messages.Add(string.Format("Error while looking for files inside path {0}. Ignoring.", path));
+                messages.Add(string.Format("Error while looking for files inside path '{0}'. Ignoring.", path));
             }
         }
 

src/CLI/Generator.cs

@@ -43,61 +43,62 @@ namespace CppSharp
         {
             if (!options.Platform.HasValue)
                 options.Platform = GetCurrentPlatform();
+
             if (Platform.IsWindows && options.Platform != TargetPlatform.Windows)
             {
-                messages.Add("Cannot create bindings for a platform other that Windows from a Windows running machine");
+                messages.Add("Cannot create bindings for a platform other that Windows from a Windows host.");
                 return false;
             }
             else if (Platform.IsMacOS && options.Platform != TargetPlatform.MacOS)
             {
-                messages.Add("Cannot create bindings for a platform other that MacOS from a MacOS running machine");
+                messages.Add("Cannot create bindings for a platform other that macOS from a macOS host.");
                 return false;
             }
             else if (Platform.IsLinux && options.Platform != TargetPlatform.Linux)
             {
-                messages.Add("Cannot create bindings for a platform other that Linux from a Linux running machine");
+                messages.Add("Cannot create bindings for a platform other that Linux from a Linux host.");
                 return false;
             }
 
             if (options.Platform != TargetPlatform.Windows && options.Kind != GeneratorKind.CSharp)
             {
-                messages.Add("Cannot create bindings for languages other than C# from a non Windows machine");
+                messages.Add("Cannot create bindings for languages other than C# from a non-Windows host.");
                 return false;
             }
 
             if (options.Platform == TargetPlatform.Linux && options.Architecture != TargetArchitecture.x64)
             {
-                messages.Add("Cannot create bindings for architectures other than x64 for Linux machines");
+                messages.Add("Cannot create bindings for architectures other than x64 for Linux targets.");
                 return false;
             }
 
             if (options.HeaderFiles.Count == 0)
             {
-                messages.Add("No source header file has been given to generate bindings from");
+                messages.Add("No source header file has been given to generate bindings from.");
                 return false;
             }
 
             if (string.IsNullOrEmpty(options.OutputNamespace))
             {
-                messages.Add("Output namespace is empty");
+                messages.Add("Output namespace not specified (see --output-namespace option).");
                 return false;
             }
 
             if (string.IsNullOrEmpty(options.OutputFileName))
             {
-                messages.Add("Output not specified");
+                messages.Add("Output directory not specified (see --output option).");
                 return false;
             }
 
             if (string.IsNullOrEmpty(options.InputLibraryName) && !options.CheckSymbols)
             {
-                messages.Add("Input library name not specified and check symbols not enabled. Either set the input library name or the check symbols flag");
+                messages.Add("Input library name not specified and check symbols option not enabled.\nEither set the input library name (see  or the check symbols flag.");
                 return false;
             }
 
             if (string.IsNullOrEmpty(options.InputLibraryName) && options.CheckSymbols && options.Libraries.Count == 0)
             {
-                messages.Add("Input library name not specified and check symbols is enabled but no libraries were given. Either set the input library name or add at least one library");
+                messages.Add("Input library name not specified and check symbols is enabled but no libraries were given.\nEither set the input library name or add at least one library.");
                 return false;
             }