system-cmd-fork added

debug.lsp

@@ -1,18 +1 @@
-
+(system-cmd-fork "ml"  "-c" "(print 123) (sleep 1) (print \"aaa\")")
-(def #sql_srv_address "stocksriddle.one")
-(def #sql_srv_port 5388)
-
-(defn exec-sql (sql)
-(do
-	(def r (tcp-client #sql_srv_address #sql_srv_port sql))
-	(print r)
-	(first (eval (parse r)))
-))
-
-(def sql "select distinct to_string(datetime, '%d.%m.%Y'),symbol,time,title from history_earnings_dates where datetime>=to_date('2022-03-02', '%Y-%m-%d') and datetime<=to_date('2022-03-19', '%Y-%m-%d')")
-(print "*" sql "*")
-(def row (exec-sql sql))
-(print row)
-
-(exit 1)
-

doc/Doc.md

@@ -88,7 +88,8 @@
 |`(read-file-lines filename lambda)`|Reads file and for each line call lambda with passing the line as a parameter|`(read-file-lines "/tmp/f.txt" (lambda (ln) (print ln))`|IO|
 |`(write-file filename content-str)`|Write a string to a file|`>>> (write-file "/tmp/a.txt" "test") => #t`|IO|
 |`(read-url url [headers] [body] [method])`|Reads URL. Returns list (status-code content)||IO|
-|`(system-cmd command_str)`|Execute system command|`>>> (system-cmd "date") => (0 "Fri Feb 25 12:35:28 CET 2022\n")`|System|
+|`(system-cmd command_str)`|Execute system command|`>>> (system-cmd-fork "ml"  "-c" "(print 123) (sleep 1) (print \"aaa\")") => (0 "") >>> 123\n aaa`|System|
+|`(system-cmd-fork cmd [par ..])`|Execute system command as an independent process|`>>> (system-cmd "date") => (0 "Fri Feb 25 12:35:28 CET 2022\n")`|System|
 |`(ls-dir dir)`|List a dir|List of directory entries|`>>> (ls-dir "/tmp") => ("." ".." "vscode-ipc-cccbe1dd-8c71-4028-a863-df975ad5887b.sock" "vscode-ipc-1163bb52-d088-41dc-80a5-81b6a7c7fa36.sock"  "vscode-ipc-630f21df-26b5-43d4-8b2e-5175d53ce317.sock")`|IO|
 |`(is-file? filename)`|Returns true if passed filename is a file|`>>> (is-file? "/tmp") => nil`|IO|
 |`(is-dir? filename)`|Returns true if passed filename is a directory|`>>> (is-dir? "/tmp") => #t`|IO|

ml.cpp

@@ -1331,6 +1331,22 @@ MlValue system_cmd(std::vector<MlValue> args, MlEnvironment &env) {
 	return exec_system_cmd(args[0].as_string());
 }
 
+// Execute system command as forked process so its independent from its parrent
+MlValue system_cmd_fork(std::vector<MlValue> args, MlEnvironment &env) {
+	eval_args(args, env);
+
+	// TODO add support for more params constructing options as one string
+	if (args.size() < 1)
+		throw MlError(MlValue("system-cmd-fork", system_cmd_fork), env, TOO_FEW_ARGS);
+
+	std::vector<std::string> exec_args;
+	exec_args.reserve(args.size());
+	for (auto const& a : args)
+			exec_args.emplace_back(a.as_string());
+
+	return exec_system_cmd_fork(exec_args);
+}
+
 
 // list directory
 MlValue ls_dir(std::vector<MlValue> args, MlEnvironment &env) {
@@ -2241,6 +2257,7 @@ std::map<const std::string, Builtin> builtin_funcs
 	std::make_pair("write-file", builtin::write_file),
 	std::make_pair("read-url", builtin::read_url),
 	std::make_pair("system-cmd", builtin::system_cmd),
+	std::make_pair("system-cmd-fork", builtin::system_cmd_fork),
 	std::make_pair("ls-dir", builtin::ls_dir),
 	std::make_pair("is-file?", builtin::is_file),
 	std::make_pair("is-dir?", builtin::is_dir),

ml_io.cpp

@@ -109,3 +109,32 @@ MlValue exec_system_cmd(const std::string &cmd) {
 
 	return std::vector<MlValue> { MlValue((long)cmd_retval), MlValue::string(cmd_output) };
 }
+
+
+MlValue exec_system_cmd_fork(const std::vector<std::string> &args) {
+	int pid = fork();
+	if (pid == 0) {
+	    // Child process, execute the command
+
+    	std::vector<char*> exec_args;
+		exec_args.reserve(args.size());
+
+	    for (auto const& a : args) 
+	        exec_args.emplace_back(const_cast<char*>(a.c_str()));
+
+    	exec_args.push_back(nullptr);	// exec must end with null
+
+    	execvp(args[0].c_str(), exec_args.data());
+
+		std::cerr << "execvp error: " << errno << ", " << strerror(errno) <<  std::endl;
+    	exit(1);	// indicate error, if here
+
+	} else if (pid > 0) {
+	    // Parent process, child process is now independent
+		return std::vector<MlValue> { MlValue((long)0), MlValue::string("") };
+
+	} else {
+	    // Fork error, still in parent process (there are no child process at this point)
+		return std::vector<MlValue> { MlValue((long)errno), MlValue::string(strerror(errno) ) };
+	}
+}

ml_io.h

@@ -14,11 +14,10 @@ bool write_file_contents(const std::string &filename, const std::string &content
 MlValue list_dir(const std::string &path);
 
 bool is_path_file(const std::string &path);
-
 bool is_path_dir(const std::string &path);
 
 bool mk_path_dir(const std::string &path);
-
 bool rm_path_dir(const std::string &path);
 
 MlValue exec_system_cmd(const std::string &path);
+MlValue exec_system_cmd_fork(const std::vector<std::string> &args);