Rulesets for table-based function params

.gitignore

@@ -30,3 +30,4 @@ __pycache__
 /fuzz/corpus/json/*
 !/fuzz/corpus/json/*.json
 *.code-workspace
+*.tar.bz2

Sources.cmake

@@ -352,6 +352,7 @@ target_sources(Luau.VM PRIVATE
     VM/include/luaconf.h
     VM/include/lualib.h
     VM/include/llsl.h
+    VM/include/llruleset_builder.h
 
     VM/src/ares.cpp
     VM/src/lapi.cpp
@@ -429,6 +430,7 @@ target_sources(Luau.VM PRIVATE
     VM/src/llprim.cpp
     VM/src/llprim.h
     VM/src/llprim_set_primitive_params.inl
+    VM/src/llruleset_builder.cpp
     VM/src/lyieldable.cpp
     VM/src/lstrbuf.cpp
     VM/src/lyieldstrlib.h

VM/include/llruleset_builder.h

@@ -0,0 +1,77 @@
+#pragma once
+#include <cstddef>
+
+struct lua_State;
+typedef int (*lua_CFunction)(lua_State* L);
+
+// Default link target: apply to the prim running the script.
+static const int SLUA_LINK_THIS = -4;
+
+// A note about C++20 porting.
+// The const char* name fields in the descriptors must have static storage duration 
+// (e.g. string literals).
+// This is not enforced at compile time,
+// but when moving to C++20 we can do something like the following:
+//
+// struct LiteralString
+// {
+//    consteval LiteralString(const char* p) noexcept : ptr(p) {}
+//    operator const char*() const noexcept { return ptr; }
+//    const char* ptr;
+// };
+// The consteval constructor ensures that only string literals can be used 
+// to construct a LiteralString.
+
+struct RulesetParamDescriptor
+{
+    const char* name;     // effective property name (pretty alias or strict fallback)
+    char        semantic; // scalar: 'i'=integer 'f'=float 's'=string 'v'=vector 'r'=rotation 'b'=boolean 'a'=asset 'k'=key
+                          // collection: 'C'=string-csv ({string} array -> escaped comma-joined string, one tag/value pair)
+                          //             'M'=string-map ({[string]:string} table -> one tag/key/value triple per entry)
+                          //             'N'=string-multi ({string} array -> one tag/value pair per element, preserving order)
+    int         tag;      // PSYS_* constant integer value
+};
+
+struct RulesetFlagDescriptor
+{
+    const char* name;       // boolean property name, e.g. "color_interp"
+    int         mask;       // bitmask, e.g. 0x01
+    int         field_tag;  // tag of the integer field holding the bits, e.g. 0 for "flags"
+};
+
+struct RulesetBuilderDef;
+
+// Build a RulesetBuilderDef from an array of descriptors.
+// The .name pointers in descs must have static storage duration (e.g. string literals).
+// Caller owns the returned pointer (process lifetime expected).
+// Descriptors are sorted by tag internally; caller order does not matter.
+RulesetBuilderDef* ruleset_builder_def_build(
+    const RulesetParamDescriptor* descs,
+    size_t                        count
+);
+
+// Attach flag-bit boolean properties to an existing def.
+// Each descriptor maps a property name to a bitmask within the integer field at field_tag.
+// The .name pointers in descs must have static storage duration (e.g. string literals).
+// Call after ruleset_builder_def_build().
+void ruleset_builder_def_add_flags(
+    RulesetBuilderDef*           def,
+    const RulesetFlagDescriptor* descs,
+    size_t                       count
+);
+
+// Serialize a params table into a flat tag/value rules list and push it onto the stack.
+// params_idx is the stack index of the params table (may be nil -- emits an empty list).
+// Flag boolean properties are merged into their backing integer field before emission.
+void slua_ruleset_serialize(lua_State* L, int params_idx, const RulesetBuilderDef* def);
+
+// Register fn as module_name.fn_name in L's globals, with def stored as upvalue 1.
+// Creates the module table if it does not yet exist; adds to it if it does.
+// Sets the module table readonly after each call.
+void slua_register_ruleset_fn(
+    lua_State*               L,
+    const char*              module_name,
+    const char*              fn_name,
+    lua_CFunction            fn,
+    const RulesetBuilderDef* def
+);