ref: 79b5ce7a3fce5e31f1060e57b2a1ddc5c21c1a43
parent: 7ac058376998864f82026ce1bb58944be142fb9a
author: kvik <kvik@a-b.xyz>
date: Tue Feb 23 15:21:14 EST 2021
lua9: flesh out standalone interpreter
--- a/lua.c
+++ b/lua.c
@@ -1,39 +1,199 @@
#include <u.h>
#include <libc.h>
+#include <bio.h>
#include <lua.h>
#include <lauxlib.h>
#include <lualib.h>
-extern int luaopen_lpeg(lua_State *L);
+char flag[] = {+ ['i'] = 0, /* interactive */
+ ['v'] = 0, /* print version */
+ ['w'] = 0, /* enable warnings */
+};
void
-main(int argc, char *argv[])
+usage(void)
{- lua_State *L;
+ fprint(2, "usage: %s [-ivw] [script] [arg ...]\n", argv0);
+ exits("usage");+}
+
+int
+iscons(int fd)
+{+ int n, c;
+ char buf[64];
- setfcr(getfcr() & ~(FPZDIV | FPOVFL | FPINVAL));
-
- if((L = luaL_newstate()) == NULL)
- sysfatal("out of memory");- luaL_openlibs(L);
- luaL_requiref(L, "lpeg", luaopen_lpeg, 1);
+ if(fd2path(fd, buf, sizeof buf) != 0)
+ sysfatal("fd2path: %r");+ n = strlen(buf);
+ c = strlen("/dev/cons");+ return n >= c && strcmp(buf + n - c, "/dev/cons") == 0;
+}
+
+void
+luaerror(lua_State *L)
+{+ fprint(2, "%s: %s\n", argv0, lua_tostring(L, -1));
lua_pop(L, 1);
+}
+int
+pcallerror(lua_State *L)
+{+ const char *m;
+
+ m = lua_tostring(L, 1);
+ if(m == nil){+ if(luaL_callmeta(L, 1, "__tostring") && lua_type(L, -1) == LUA_TSTRING)
+ return 1;
+ else
+ m = lua_pushfstring(L,
+ "(error object is a %s value)", luaL_typename(L, 1));
+ }
+ luaL_traceback(L, L, m, 1);
+ return 1;
+}
+
+int
+pcall(lua_State *L, int narg, int nres)
+{+ int r, base;
+
+ base = lua_gettop(L) - narg;
+ lua_pushcfunction(L, pcallerror);
+ lua_insert(L, base);
+ r = lua_pcall(L, narg, nres, base);
+ lua_remove(L, base);
+ return r;
+}
+
+int
+pushargs(lua_State *L)
+{+ int i, n;
+
+ /* Push the 'arg' array to stack */
+ if(lua_getglobal(L, "arg") != LUA_TTABLE)
+ luaL_error(L, "'arg' is not a table");
+ n = luaL_len(L, -1);
+ luaL_checkstack(L, n + 1, "too many arguments");
+ for(i = 1; i <= n; i++)
+ lua_rawgeti(L, -i, i);
+ lua_remove(L, -i);
+ return n;
+}
+
+int
+runrepl(lua_State *L)
+{+ int r, narg;
+ char *ln;
+ Biobuf bin;
+
+ if(Binit(&bin, 0, OREAD) == -1)
+ sysfatal("Binit: %r");+ r = LUA_OK;
+ while(fprint(2, "> "), (ln = Brdstr(&bin, '\n', 1)) != nil){+ if(luaL_loadstring(L, ln) != LUA_OK){+ luaerror(L);
+ continue;
+ }
+ narg = pushargs(L);
+ if((r = pcall(L, narg, LUA_MULTRET)) != LUA_OK)
+ luaerror(L);
+ }
+ Bterm(&bin);
+ return r;
+}
+
+int
+runfile(lua_State *L, char *file)
+{+ int narg, r;
+
+ if((r = luaL_loadfile(L, file)) == LUA_OK){+ narg = pushargs(L);
+ r = pcall(L, narg, LUA_MULTRET);
+ }
+ if(r != LUA_OK)
+ luaerror(L);
+ return r;
+}
+
+int
+luamain(lua_State *L)
+{+ int argc, i;
+ char **argv, *file;
+
+ argc = lua_tointeger(L, 1);
+ argv = lua_touserdata(L, 2);
+ file = argv[0];
+
+ if(flag['w'])
+ lua_warning(L, "@on", 0);
+
+ /* Signal for libraries to ignore LUA_* env. vars */
+ lua_pushboolean(L, 1);
+ lua_setfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
+ luaL_openlibs(L);
+
+ /* GC in generational mode */
+ lua_gc(L, LUA_GCGEN, 0, 0);
+
+ /* Create global 'arg' table */
lua_createtable(L, argc, 0);
- for(int i = 0; i < argc; i++){+ lua_pushstring(L, argv0);
+ lua_rawseti(L, -2, 0);
+ for(i = 1; i < argc; i++){lua_pushstring(L, argv[i]);
lua_rawseti(L, -2, i);
}
lua_setglobal(L, "arg");
+
+ if(file == nil){+ file = "/fd/0";
+ if(flag['i'] && iscons(0))
+ file = nil;
+ }
+ if(file != nil)
+ runfile(L, file);
+ if(flag['i'])
+ runrepl(L);
- if(luaL_loadfile(L, argv[1]) != LUA_OK)
- sysfatal("%s", lua_tostring(L, -1));- for(int i = 1; i < argc; i++)
- lua_pushstring(L, argv[i]);
- if(lua_pcall(L, argc-1, LUA_MULTRET, 0) != LUA_OK)
- sysfatal("%s", lua_tostring(L, -1));- lua_close(L);
+ lua_pushboolean(L, 1);
+ return 1;
+}
+
+void
+main(int argc, char *argv[])
+{+ int r, v;
+ lua_State *L;
- exits(nil);
+ ARGBEGIN{+ case 'i': flag['i'] = 1; break;
+ case 'v': flag['v'] = 1; break;
+ case 'w': flag['w'] = 1; break;
+ default: usage();
+ }ARGEND;
+ if(flag['v']){+ print("%s\n", LUA_COPYRIGHT);+ exits(nil);
+ }
+
+ setfcr(getfcr() & ~(FPZDIV | FPOVFL | FPINVAL));
+ if((L = luaL_newstate()) == NULL)
+ sysfatal("out of memory");+ lua_pushcfunction(L, luamain);
+ lua_pushinteger(L, argc);
+ lua_pushlightuserdata(L, argv);
+ r = lua_pcall(L, 2, 1, 0);
+ if(r != LUA_OK)
+ luaerror(L);
+ v = lua_toboolean(L, -1);
+ lua_close(L);
+ exits(r == LUA_OK && v == 1 ? nil : "errors");
}