From 46beca5bed8a7700b18100fe48a78373be5055f9 Mon Sep 17 00:00:00 2001 From: Roberto Ierusalimschy Date: Mon, 10 Dec 2018 13:46:03 -0200 Subject: [PATCH] Better error messages for some polymorphic functions New auxiliary functions/macros 'luaL_argexpected'/'luaL_typeerror' ease the creation of error messages such as bad argument #2 to 'setmetatable' (nil or table expected, got boolean) (The novelty being the "got boolean" part...) --- lauxlib.c | 6 +++--- lauxlib.h | 5 +++++ lbaselib.c | 7 +++---- lcorolib.c | 2 +- ldblib.c | 3 +-- lstrlib.c | 4 ++-- manual/manual.of | 26 ++++++++++++++++++++++++++ 7 files changed, 41 insertions(+), 12 deletions(-) diff --git a/lauxlib.c b/lauxlib.c index fd4acbd1..769586b6 100644 --- a/lauxlib.c +++ b/lauxlib.c @@ -185,7 +185,7 @@ LUALIB_API int luaL_argerror (lua_State *L, int arg, const char *extramsg) { } -static int typeerror (lua_State *L, int arg, const char *tname) { +int luaL_typeerror (lua_State *L, int arg, const char *tname) { const char *msg; const char *typearg; /* name for the type of the actual argument */ if (luaL_getmetafield(L, arg, "__name") == LUA_TSTRING) @@ -200,7 +200,7 @@ static int typeerror (lua_State *L, int arg, const char *tname) { static void tag_error (lua_State *L, int arg, int tag) { - typeerror(L, arg, lua_typename(L, tag)); + luaL_typeerror(L, arg, lua_typename(L, tag)); } @@ -339,7 +339,7 @@ LUALIB_API void *luaL_testudata (lua_State *L, int ud, const char *tname) { LUALIB_API void *luaL_checkudata (lua_State *L, int ud, const char *tname) { void *p = luaL_testudata(L, ud, tname); - if (p == NULL) typeerror(L, ud, tname); + luaL_argexpected(L, p != NULL, ud, tname); return p; } diff --git a/lauxlib.h b/lauxlib.h index 9ec0f531..e5d378ae 100644 --- a/lauxlib.h +++ b/lauxlib.h @@ -48,6 +48,7 @@ LUALIB_API int (luaL_getmetafield) (lua_State *L, int obj, const char *e); LUALIB_API int (luaL_callmeta) (lua_State *L, int obj, const char *e); LUALIB_API const char *(luaL_tolstring) (lua_State *L, int idx, size_t *len); LUALIB_API int (luaL_argerror) (lua_State *L, int arg, const char *extramsg); +LUALIB_API int (luaL_typeerror) (lua_State *L, int arg, const char *tname); LUALIB_API const char *(luaL_checklstring) (lua_State *L, int arg, size_t *l); LUALIB_API const char *(luaL_optlstring) (lua_State *L, int arg, @@ -126,6 +127,10 @@ LUALIB_API void (luaL_requiref) (lua_State *L, const char *modname, #define luaL_argcheck(L, cond,arg,extramsg) \ ((void)((cond) || luaL_argerror(L, (arg), (extramsg)))) + +#define luaL_argexpected(L,cond,arg,tname) \ + ((void)((cond) || luaL_typeerror(L, (arg), (tname)))) + #define luaL_checkstring(L,n) (luaL_checklstring(L, (n), NULL)) #define luaL_optstring(L,n,d) (luaL_optlstring(L, (n), (d), NULL)) diff --git a/lbaselib.c b/lbaselib.c index e776c2a2..201c93e3 100644 --- a/lbaselib.c +++ b/lbaselib.c @@ -125,8 +125,7 @@ static int luaB_getmetatable (lua_State *L) { static int luaB_setmetatable (lua_State *L) { int t = lua_type(L, 2); luaL_checktype(L, 1, LUA_TTABLE); - luaL_argcheck(L, t == LUA_TNIL || t == LUA_TTABLE, 2, - "nil or table expected"); + luaL_argexpected(L, t == LUA_TNIL || t == LUA_TTABLE, 2, "nil or table"); if (luaL_getmetafield(L, 1, "__metatable") != LUA_TNIL) return luaL_error(L, "cannot change a protected metatable"); lua_settop(L, 2); @@ -145,8 +144,8 @@ static int luaB_rawequal (lua_State *L) { static int luaB_rawlen (lua_State *L) { int t = lua_type(L, 1); - luaL_argcheck(L, t == LUA_TTABLE || t == LUA_TSTRING, 1, - "table or string expected"); + luaL_argexpected(L, t == LUA_TTABLE || t == LUA_TSTRING, 1, + "table or string"); lua_pushinteger(L, lua_rawlen(L, 1)); return 1; } diff --git a/lcorolib.c b/lcorolib.c index 9038f9fb..34462b53 100644 --- a/lcorolib.c +++ b/lcorolib.c @@ -20,7 +20,7 @@ static lua_State *getco (lua_State *L) { lua_State *co = lua_tothread(L, 1); - luaL_argcheck(L, co, 1, "thread expected"); + luaL_argexpected(L, co, 1, "thread"); return co; } diff --git a/ldblib.c b/ldblib.c index 20010842..ada35250 100644 --- a/ldblib.c +++ b/ldblib.c @@ -55,8 +55,7 @@ static int db_getmetatable (lua_State *L) { static int db_setmetatable (lua_State *L) { int t = lua_type(L, 2); - luaL_argcheck(L, t == LUA_TNIL || t == LUA_TTABLE, 2, - "nil or table expected"); + luaL_argexpected(L, t == LUA_TNIL || t == LUA_TTABLE, 2, "nil or table"); lua_settop(L, 2); lua_setmetatable(L, 1); return 1; /* return 1st argument */ diff --git a/lstrlib.c b/lstrlib.c index a635e9d4..e9c60c0f 100644 --- a/lstrlib.c +++ b/lstrlib.c @@ -857,9 +857,9 @@ static int str_gsub (lua_State *L) { lua_Integer n = 0; /* replacement count */ MatchState ms; luaL_Buffer b; - luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING || + luaL_argexpected(L, tr == LUA_TNUMBER || tr == LUA_TSTRING || tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3, - "string/function/table expected"); + "string/function/table"); luaL_buffinit(L, &b); if (anchor) { p++; lp--; /* skip anchor character */ diff --git a/manual/manual.of b/manual/manual.of index 8b5e5d93..0e8e3d72 100644 --- a/manual/manual.of +++ b/manual/manual.of @@ -4979,6 +4979,19 @@ This function never returns. } +@APIEntry{ +void luaL_argexpected (lua_State *L, + int cond, + int arg, + const char *tname);| +@apii{0,0,v} + +Checks whether @id{cond} is true. +If it is not, raises an error about the type of the argument @id{arg} +with a standard message @seeF{luaL_typeerror}. + +} + @APIEntry{typedef struct luaL_Buffer luaL_Buffer;| Type for a @def{string buffer}. @@ -5713,6 +5726,19 @@ to start the traceback. } +@APIEntry{const char *luaL_typeerror (lua_State *L, + int arg, + const char *tname);| +@apii{0,0,v} + +Raises a type error for argument @id{arg} +of the @N{C function} that called it, +using a standard message; +@id{tname} is a @Q{name} for the expected type. +This function never returns. + +} + @APIEntry{const char *luaL_typename (lua_State *L, int index);| @apii{0,0,-}