Add support for shell script parameters

Now %sh{ ... } can access positional parameters through
standard shell construct, allowing simple handling of variable
parameters.

def command accepts -shell-params flag to use this facility.

src/command_manager.cc

@@ -211,6 +211,7 @@ void CommandManager::execute_single_command(const CommandParameters& params,
 
 void CommandManager::execute(const String& command_line,
                              Context& context,
+                             const memoryview<String>& shell_params,
                              const EnvVarMap& env_vars)
 {
     TokenList tokens = parse(command_line);
@@ -223,7 +224,8 @@ void CommandManager::execute(const String& command_line,
         if (it->type() == Token::Type::ShellExpand)
         {
             String output = ShellManager::instance().eval(it->content(),
-                                                          context, env_vars);
+                                                          context, shell_params,
+                                                          env_vars);
             TokenList shell_tokens = parse(output);
             it = tokens.erase(it);
             for (auto& token : shell_tokens)

src/command_manager.hh

@@ -53,7 +53,8 @@ class CommandManager : public Singleton<CommandManager>
 {
 public:
     void execute(const String& command_line, Context& context,
-                 const EnvVarMap& env_vars = EnvVarMap());
+                 const memoryview<String>& shell_params = {},
+                 const EnvVarMap& env_vars = {});
 
     Completions complete(const Context& context,
                          const String& command_line, CharCount cursor_pos);

src/commands.cc

@@ -534,6 +534,7 @@ void define_command(const CommandParameters& params, Context& context)
 {
     ParametersParser parser(params,
                             { { "env-params", false },
+                              { "shell-params", false },
                               { "allow-override", false },
                               { "shell-completion", true } });
 
@@ -552,10 +553,16 @@ void define_command(const CommandParameters& params, Context& context)
     if (parser.has_option("env-params"))
     {
         cmd = [=](const CommandParameters& params, Context& context) {
-            CommandManager::instance().execute(commands, context,
+            CommandManager::instance().execute(commands, context, {},
                                                params_to_env_var_map(params));
         };
     }
+    if (parser.has_option("shell-params"))
+    {
+        cmd = [=](const CommandParameters& params, Context& context) {
+            CommandManager::instance().execute(commands, context, params, {});
+        };
+    }
     else
     {
          cmd = [=](const CommandParameters& params, Context& context) {
@@ -571,10 +578,11 @@ void define_command(const CommandParameters& params, Context& context)
         auto completer = [=](const Context& context, const CommandParameters& params,
                              size_t token_to_complete, CharCount pos_in_token)
         {
-           EnvVarMap vars = params_to_env_var_map(params);
-           vars["token_to_complete"] = int_to_str(token_to_complete);
-           vars["pos_in_token"]      = int_to_str((int)pos_in_token);
-           String output = ShellManager::instance().eval(shell_cmd, context, vars);
+           EnvVarMap vars = {
+               {"token_to_complete", int_to_str(token_to_complete) },
+               { "pos_in_token",     int_to_str((int)pos_in_token) }
+           };
+           String output = ShellManager::instance().eval(shell_cmd, context, params, vars);
            return split(output, '\n');
         };
         CommandManager::instance().register_command(cmd_name, cmd, completer);

src/main.cc

@@ -102,7 +102,7 @@ void do_pipe(Context& context)
             std::vector<String> strings;
             for (auto& sel : const_cast<const Editor&>(context.editor()).selections())
                 strings.push_back(ShellManager::instance().pipe(String(sel.begin(), sel.end()),
-                                                                cmdline, context, {}));
+                                                                cmdline, context, {}, {}));
             editor.replace(strings);
         });
 

src/shell_manager.cc

@@ -16,13 +16,15 @@ ShellManager::ShellManager()
 }
 
 String ShellManager::eval(const String& cmdline, const Context& context,
+                          const memoryview<String>& params,
                           const EnvVarMap& env_vars)
 {
-    return pipe("", cmdline, context, env_vars);
+    return pipe("", cmdline, context, params, env_vars);
 }
 
 String ShellManager::pipe(const String& input,
                           const String& cmdline, const Context& context,
+                          const memoryview<String>& params,
                           const EnvVarMap& env_vars)
 {
     int write_pipe[2]; // child stdin
@@ -114,8 +116,14 @@ String ShellManager::pipe(const String& input,
 
             ++it;
         }
+        std::vector<const char*> execparams = { "sh", "-c", cmdline.c_str() };
+        if (not params.empty())
+            execparams.push_back("sh");
+        for (auto& param : params)
+            execparams.push_back(param.c_str());
+        execparams.push_back(NULL);
 
-        execlp("sh", "sh", "-c", cmdline.c_str(), NULL);
+        execvp("sh", (char* const*)execparams.data());
         exit(-1);
     }
     catch (...) { exit(-1); }

src/shell_manager.hh

@@ -19,10 +19,12 @@ public:
     ShellManager();
 
     String eval(const String& cmdline, const Context& context,
+                const memoryview<String>& params,
                 const EnvVarMap& env_vars);
 
     String pipe(const String& input,
                 const String& cmdline, const Context& context,
+                const memoryview<String>& params,
                 const EnvVarMap& env_vars);
 
     void register_env_var(const String& regex, EnvVarRetriever retriever);