text: /*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
  │vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
  ╚──────────────────────────────────────────────────────────────────────────────╝
  │                                                                              │
  │  Lua                                                                         │
  │  Copyright © 2004-2021 Lua.org, PUC-Rio.                                     │
  │                                                                              │
  │  Permission is hereby granted, free of charge, to any person obtaining       │
  │  a copy of this software and associated documentation files (the             │
  │  "Software"), to deal in the Software without restriction, including         │
  │  without limitation the rights to use, copy, modify, merge, publish,         │
  │  distribute, sublicense, and/or sell copies of the Software, and to          │
  │  permit persons to whom the Software is furnished to do so, subject to       │
  │  the following conditions:                                                   │
  │                                                                              │
  │  The above copyright notice and this permission notice shall be              │
  │  included in all copies or substantial portions of the Software.             │
  │                                                                              │
  │  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,             │
  │  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF          │
  │  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.      │
  │  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY        │
  │  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,        │
  │  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE           │
  │  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                      │
  │                                                                              │
  ╚─────────────────────────────────────────────────────────────────────────────*/
  #define lua_c
  #include "libc/calls/calls.h"
  #include "libc/calls/struct/sigaction.h"
  #include "libc/dce.h"
  #include "libc/errno.h"
  #include "libc/intrin/kprintf.h"
  #include "libc/log/log.h"
  #include "libc/runtime/gc.h"
  #include "libc/runtime/stack.h"
  #include "libc/sock/sock.h"
  #include "libc/str/str.h"
  #include "libc/sysv/consts/exit.h"
  #include "libc/sysv/consts/poll.h"
  #include "libc/sysv/consts/sa.h"
  #include "libc/x/x.h"
  #include "third_party/linenoise/linenoise.h"
  #include "third_party/lua/cosmo.h"
  #include "third_party/lua/lauxlib.h"
  #include "third_party/lua/lprefix.h"
  #include "third_party/lua/lrepl.h"
  #include "third_party/lua/lua.h"
  #include "third_party/lua/lualib.h"
  #include "tool/args/args.h"
  // clang-format off
  
  asm(".ident\t\"\\n\\n\
  Lua 5.4.3 (MIT License)\\n\
  Copyright 1994–2021 Lua.org, PUC-Rio.\"");
  asm(".include \"libc/disclaimer.inc\"");
  
  STATIC_STACK_SIZE(0x40000);
  
  #if !defined(LUA_PROGNAME)
  #define LUA_PROGNAME		"lua"
  #endif
  
  #if !defined(LUA_INIT_VAR)
  #define LUA_INIT_VAR		"LUA_INIT"
  #endif
  
  #define LUA_INITVARVERSION	LUA_INIT_VAR LUA_VERSUFFIX
  
  
  static lua_State *globalL = NULL;
  static const char *progname = LUA_PROGNAME;
  
  
  static bool lua_stdin_is_tty(void) {
    return isatty(0);
  }
  
  
  static void print_usage (const char *badoption) {
    lua_writestringerror("%s: ", progname);
    if (badoption[1] == 'e' || badoption[1] == 'l')
      lua_writestringerror("'%s' needs argument\n", badoption);
    else
      lua_writestringerror("unrecognized option '%s'\n", badoption);
    lua_writestringerror(
    "usage: %s [options] [script [args]]\n"
    "Available options are:\n"
    "  -e stat  execute string 'stat'\n"
    "  -i       enter interactive mode after executing 'script'\n"
    "  -l name  require library 'name' into global 'name'\n"
    "  -v       show version information\n"
    "  -E       ignore environment variables\n"
    "  -W       turn warnings on\n"
    "  --       stop handling options\n"
    "  -        stop handling options and execute stdin\n"
    ,
    progname);
  }
  
  
  static void print_version (void) {
    lua_writestring(LUA_COPYRIGHT, strlen(LUA_COPYRIGHT));
    lua_writeline();
  }
  
  
  /*
  ** Create the 'arg' table, which stores all arguments from the
  ** command line ('argv'). It should be aligned so that, at index 0,
  ** it has 'argv[script]', which is the script name. The arguments
  ** to the script (everything after 'script') go to positive indices;
  ** other arguments (before the script name) go to negative indices.
  ** If there is no script name, assume interpreter's name as base.
  */
  static void createargtable (lua_State *L, char **argv, int argc, int script) {
    int i, narg;
    if (script == argc) script = 0;  /* no script name? */
    narg = argc - (script + 1);  /* number of positive indices */
    lua_createtable(L, narg, script + 1);
    for (i = 0; i < argc; i++) {
      lua_pushstring(L, argv[i]);
      lua_rawseti(L, -2, i - script);
    }
    lua_setglobal(L, "arg");
  }
  
  
  static int dochunk (lua_State *L, int status) {
    if (status == LUA_OK) status = lua_runchunk(L, 0, 0);
    return lua_report(L, status);
  }
  
  
  static int dofile (lua_State *L, const char *name) {
    return dochunk(L, luaL_loadfile(L, name));
  }
  
  
  static int dostring (lua_State *L, const char *s, const char *name) {
    return dochunk(L, luaL_loadbuffer(L, s, strlen(s), name));
  }
  
  
  /*
  ** Calls 'require(name)' and stores the result in a global variable
  ** with the given name.
  */
  static int dolibrary (lua_State *L, const char *name) {
    int status;
    lua_getglobal(L, "require");
    lua_pushstring(L, name);
    status = lua_runchunk(L, 1, 1);  /* call 'require(name)' */
    if (status == LUA_OK)
      lua_setglobal(L, name);  /* global[name] = require return */
    return lua_report(L, status);
  }
  
  
  /*
  ** Push on the stack the contents of table 'arg' from 1 to #arg
  */
  static int pushargs (lua_State *L) {
    int i, n;
    if (lua_getglobal(L, "arg") != LUA_TTABLE)
      luaL_error(L, "'arg' is not a table");
    n = (int)luaL_len(L, -1);
    luaL_checkstack(L, n + 3, "too many arguments to script");
    for (i = 1; i <= n; i++)
      lua_rawgeti(L, -i, i);
    lua_remove(L, -i);  /* remove table from the stack */
    return n;
  }
  
  
  static int handle_script (lua_State *L, char **argv) {
    int status;
    const char *fname = argv[0];
    if (strcmp(fname, "-") == 0 && strcmp(argv[-1], "--") != 0)
      fname = NULL;  /* stdin */
    status = luaL_loadfile(L, fname);
    if (status == LUA_OK) {
      int n = pushargs(L);  /* push arguments to script */
      status = lua_runchunk(L, n, LUA_MULTRET);
    }
    return lua_report(L, status);
  }
  
  
  /* bits of various argument indicators in 'args' */
  #define has_error	1	/* bad option */
  #define has_i		2	/* -i */
  #define has_v		4	/* -v */
  #define has_e		8	/* -e */
  #define has_E		16	/* -E */
  
  
  /*
  ** Traverses all arguments from 'argv', returning a mask with those
  ** needed before running any Lua code (or an error code if it finds
  ** any invalid argument). 'first' returns the first not-handled argument
  ** (either the script name or a bad argument in case of error).
  */
  static int collectargs (char **argv, int *first) {
    int args = 0;
    int i;
    for (i = 1; argv[i] != NULL; i++) {
      *first = i;
      if (argv[i][0] != '-')  /* not an option? */
          return args;  /* stop handling options */
      switch (argv[i][1]) {  /* else check option */
        case '-':  /* '--' */
          if (argv[i][2] != '\0')  /* extra characters after '--'? */
            return has_error;  /* invalid option */
          *first = i + 1;
          return args;
        case '\0':  /* '-' */
          return args;  /* script "name" is '-' */
        case 'E':
          if (argv[i][2] != '\0')  /* extra characters? */
            return has_error;  /* invalid option */
          args |= has_E;
          break;
        case 'W':
          if (argv[i][2] != '\0')  /* extra characters? */
            return has_error;  /* invalid option */
          break;
        case 'i':
          args |= has_i;  /* (-i implies -v) *//* FALLTHROUGH */
        case 'v':
          if (argv[i][2] != '\0')  /* extra characters? */
            return has_error;  /* invalid option */
          args |= has_v;
          break;
        case 'e':
          args |= has_e;  /* FALLTHROUGH */
        case 'l':  /* both options need an argument */
          if (argv[i][2] == '\0') {  /* no concatenated argument? */
            i++;  /* try next 'argv' */
            if (argv[i] == NULL || argv[i][0] == '-')
              return has_error;  /* no next argument or it is another option */
          }
          break;
        default:  /* invalid option */
          return has_error;
      }
    }
    *first = i;  /* no script name */
    return args;
  }
  
  
  /*
  ** Processes options 'e' and 'l', which involve running Lua code, and
  ** 'W', which also affects the state.
  ** Returns 0 if some code raises an error.
  */
  static int runargs (lua_State *L, char **argv, int n) {
    int i;
    for (i = 1; i < n; i++) {
      int option = argv[i][1];
      lua_assert(argv[i][0] == '-');  /* already checked */
      switch (option) {
        case 'e':  case 'l': {
          int status;
          const char *extra = argv[i] + 2;  /* both options need an argument */
          if (*extra == '\0') extra = argv[++i];
          lua_assert(extra != NULL);
          status = (option == 'e')
                   ? dostring(L, extra, "=(command line)")
                   : dolibrary(L, extra);
          if (status != LUA_OK) return 0;
          break;
        }
        case 'W':
          lua_warning(L, "@on", 0);  /* warnings on */
          break;
      }
    }
    return 1;
  }
  
  
  static int handle_luainit (lua_State *L) {
    const char *name = "=" LUA_INITVARVERSION;
    const char *init = getenv(name + 1);
    if (init == NULL) {
      name = "=" LUA_INIT_VAR;
      init = getenv(name + 1);  /* try alternative name */
    }
    if (init == NULL) return LUA_OK;
    else if (init[0] == '@')
      return dofile(L, init+1);
    else
      return dostring(L, init, name);
  }
  
  
  /*
  ** Do the REPL: repeatedly read (load) a line, evaluate (call) it, and
  ** print any results.
  */
  static void doREPL (lua_State *L) {
    int status;
    const char *oldprogname = progname;
    progname = NULL;  /* no 'progname' on errors in interactive mode */
    lua_initrepl(L, LUA_PROGNAME);
    for (;;) {
      if (lua_repl_isterminal)
        linenoiseEnableRawMode(0);
   TryAgain:
      status = lua_loadline(L);
      if (status == -2 && errno == EAGAIN) {
        errno = 0;
        poll(&(struct pollfd){0, POLLIN}, 1, -1);
        goto TryAgain;
      }
      if (lua_repl_isterminal)
        linenoiseDisableRawMode();
      if (status == -1) {
        break;
      } else if (status == -2) {
        lua_pushfstring(L, "read error: %s", strerror(errno));
        lua_report(L, status);
        lua_freerepl();
        progname = oldprogname;
        return;
      }
      if (status == LUA_OK)
        status = lua_runchunk(L, 0, LUA_MULTRET);
      if (status == LUA_OK) {
        lua_l_print(L);
      } else {
        lua_report(L, status);
      }
    }
    lua_freerepl();
    lua_settop(L, 0);  /* clear stack */
    progname = oldprogname;
  }
  
  /* }================================================================== */
  
  
  /*
  ** Main body of stand-alone interpreter (to be called in protected mode).
  ** Reads the options and handles them all.
  */
  static int pmain (lua_State *L) {
    int argc = (int)lua_tointeger(L, 1);
    char **argv = (char **)lua_touserdata(L, 2);
    int script;
    int args = collectargs(argv, &script);
    luaL_checkversion(L);  /* check that interpreter has correct version */
    if (argv[0] && argv[0][0]) progname = argv[0];
    if (args == has_error) {  /* bad arg? */
      print_usage(argv[script]);  /* 'script' has index of bad arg. */
      return 0;
    }
    if (args & has_v)  /* option '-v'? */
      print_version();
    if (args & has_E) {  /* option '-E'? */
      lua_pushboolean(L, 1);  /* signal for libraries to ignore env. vars. */
      lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
    }
    luaL_openlibs(L);  /* open standard libraries */
    createargtable(L, argv, argc, script);  /* create table 'arg' */
    lua_gc(L, LUA_GCGEN, 0, 0);  /* GC in generational mode */
    if (!(args & has_E)) {  /* no option '-E'? */
      if (handle_luainit(L) != LUA_OK)  /* run LUA_INIT */
        return 0;  /* error running LUA_INIT */
    }
    if (!runargs(L, argv, script))  /* execute arguments -e and -l */
      return 0;  /* something failed */
    if (script < argc &&  /* execute main script (if there is one) */
        handle_script(L, argv + script) != LUA_OK)
      return 0;
    if (args & has_i)  /* -i option? */
      doREPL(L);  /* do read-eval-print loop */
    else if (script == argc && !(args & (has_e | has_v))) {  /* no arguments? */
      if (lua_stdin_is_tty()) {  /* running in interactive mode? */
        print_version();
        doREPL(L);  /* do read-eval-print loop */
      }
      else dofile(L, NULL);  /* executes stdin as a file */
    }
    lua_pushboolean(L, 1);  /* signal no errors */
    return 1;
  }
  
  
  int main (int argc, char **argv) {
    lua_State *L;
    int status, result;
    LoadZipArgs(&argc, &argv);
    if (IsModeDbg()) {
      ShowCrashReports();
    }
    L = luaL_newstate();  /* create state */
    if (L == NULL) {
      lua_l_message(argv[0], "cannot create state: not enough memory");
      return EXIT_FAILURE;
    }
    lua_pushcfunction(L, &pmain);  /* to call 'pmain' in protected mode */
    lua_pushinteger(L, argc);  /* 1st argument */
    lua_pushlightuserdata(L, argv); /* 2nd argument */
    status = lua_pcall(L, 2, 1, 0);  /* do the call */
    result = lua_toboolean(L, -1);  /* get result */
    lua_report(L, status);
    lua_close(L);
    if (IsModeDbg()) {
      CheckForMemoryLeaks();
    }
    return (result && status == LUA_OK) ? EXIT_SUCCESS : EXIT_FAILURE;
  }
  