Bruce/lua-immutable
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Added default tostring.

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This commit is contained in:
Bruce Hill 2018-02-09 16:46:33 -08:00
parent 8050fa3804
commit 0f15ee34d7
1 changed files with 69 additions and 12 deletions
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81
limmutable.c
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@ -1,6 +1,16 @@
/*
* immutable.c
* An immutable table library.
* An immutable table library by Bruce Hill. This library returns a single function
* that can be used to declare immutable classes, like so:
*
* immutable = require 'immutable'
* local Foo = immutable({"baz","qux"})
* local foo = Foo("hello", 99)
* assert(not pcall(function() foo.x = 'mutable' end))
* local t = {[foo]="it works"}
* assert(t[Foo("hello", 99)] == "it works")
*
* Instances *are* garbage collected.
*/
#include "lua.h"
@ -199,14 +209,62 @@ static int Lindex(lua_State *L)
}
lua_pop(L, 1);
// Stack: [mt]
lua_getfield(L, -1, "__methods");
// Stack: [mt, __methods]
lua_pushvalue(L, 2);
// Stack: [mt, __methods, key]
// Stack: [mt, key]
lua_gettable(L, -2);
return 1;
}
static int Ltostring(lua_State *L)
{
luaL_Buffer b;
luaL_buffinit(L, &b);
lua_getmetatable(L, 1);
// Stack: [mt]
lua_getfield(L, -1, "name");
if (!lua_isnil(L, -1)) {
luaL_addvalue(&b);
} else {
lua_pop(L, 1);
}
luaL_addstring(&b, "(");
lua_getfield(L, -1, "__instances");
// Stack: [mt, buckets]
lua_rawgeti(L, -1, *((lua_Integer*)lua_touserdata(L, 1)));
// Stack: [mt, buckets, bucket]
lua_pushvalue(L, 1);
// Stack: [mt, buckets, bucket, inst_udata]
lua_rawget(L, -2);
// Stack: [mt, buckets, bucket, inst_table]
lua_getfield(L, -4, "__fields");
// Stack: [mt, buckets, bucket, inst_table, fields]
lua_pushnil(L);
int needs_comma = 0;
while (lua_next(L, -2) != 0) {
// Stack: [mt, buckets, bucket, inst_table, fields, i, fieldname]
if (needs_comma) {
luaL_addstring(&b, ", ");
} else {
needs_comma = 1;
}
luaL_addvalue(&b);
// Stack: [mt, buckets, bucket, inst_table, fields, i]
luaL_addstring(&b, "=");
lua_rawgeti(L, -3, lua_tonumber(L, -1));
// Stack: [mt, buckets, bucket, inst_table, fields, i, value]
luaL_addvalue(&b);
// Stack: [mt, buckets, bucket, inst_table, fields, i]
}
luaL_addstring(&b, ")");
luaL_pushresult(&b);
return 1;
}
static const luaL_Reg R[] =
{
{ "__len", Llen},
@ -223,6 +281,8 @@ static int Lmake_class(lua_State *L)
// CLS = {}
lua_newtable(L);
// Stack: [CLS]
lua_pushcfunction(L, Ltostring);
lua_setfield(L, -2, "__tostring");
// If metamethods were passed in, copy them over
if (n_args > 2) {
@ -252,25 +312,22 @@ static int Lmake_class(lua_State *L)
lua_setfield(L, -2, "__fields");
// Stack: [CLS]
lua_newtable(L);
// Stack: [CLS, __methods]
// If methods were passed in, copy them over
if (n_args > 1) {
// Stack: [
lua_pushnil(L);
// Stack: [CLS, __methods, nil]
// Stack: [CLS, nil]
while (lua_next(L, 2) != 0) {
// Stack: [CLS, method_name, method_value]
lua_pushvalue(L, -2);
lua_pushvalue(L, -2);
// Stack: [CLS, __methods, method_name, method_value, method_name, method_value]
// Stack: [CLS, method_name, method_value, method_name, method_value]
lua_settable(L, -5);
// Stack: [CLS, __methods, method_name, method_value]
// Stack: [CLS, method_name, method_value]
lua_pop(L, 1);
// Stack: [CLS, __methods, method_name]
// Stack: [CLS, method_name]
}
// Stack: [CLS, __methods]
}
lua_setfield(L, -2, "__methods");
// Stack: [CLS]
// Populate __len, __eq, __index, new, etc.