Generate `EmbeddedBuiltinDefinitions.cpp` by tapple · Pull Request #181 · secondlife/lsl-definitions

tapple · 2026-07-11T22:33:25Z

Generate EmbeddedBuiltinDefinitions.cpp so that luau-analyze knows about ll functions and such.

This generates a file intended for Luau 0.725 - 0.730

Closes Create a generator for EmbeddedBuiltinDefinitions.cpp #122
Diff of generated EmbeddedBuiltinDefinitions.cpp against slua 0.729 tapple/lsl-definitions#3

tapple · 2026-07-13T16:17:24Z

@@ -0,0 +1,523 @@
+// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
+#include "Luau/BuiltinDefinitions.h"


My design thoughts regarding the structure of EmbeddedBuiltinDefinitions.cpp:

Logically, the whole module just needs to return a single string (ignoring the types library). So, it could just embed the existing secondlife.d.luau file as-is in the cpp source code

The technical reason not to is fflags.

SLua's version (Luau 0.710)

Luau's version (Luau 0.725)

SLua/Luau 0.710 use 2 fflags:

LuauTypeCheckerUdtfRenameClassToExtern

LuauMorePermissiveNewtableType

Both fflags only affect the types library, which this repository doesn't touch

Luau 0.723 uses 5 fflags:

LuauIntegerLibrary

LuauIntegerType2

LuauAllowGlobalDeclarationToBeCalledClass

DebugLuauUserDefinedClasses

LuauUdtfTypeIsSubtypeOf

fflags 1-2 affect the inclusion of the integer library and 2 buffer functions
fflags 3-4 affect the inclusion of the class library
fflags 2 and 5 affect the types library, which this repository doesn't care about

@HaroldCindy mentioned in the 2026-06-23 Server User Group that SLua is going to merge upstream from Luau soon, and that it will leave the integer and class libraries disabled by fflags for now.
Therefore, I think it best to match the structure of the generated file as closely to upstream as possible, so that it can keep the fflags working. Is that ok?

I chose to generate a file for any of Luau 725, 726, 727, 728, or 729 because:

EmbeddedBuiltinDefinitions.cpp is identical in those 5 versions

it has minimal fflags that my generator needs to worry about (especially no fflags that switch between 2 definitions of one function, which the generator doesn't support

The file has been stable for quite a few versions (5), but there's upcoming PR's that will add more FFlags to worry about:

Improve the os.difftime and os.time type definitions luau-lang/luau#2337

Fix utf8.offset type luau-lang/luau#2378

Fix integer.create and fromstring type definitions luau-lang/luau#2540

tapple · 2026-07-13T16:18:07Z

@@ -0,0 +1,523 @@
+// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
+#include "Luau/BuiltinDefinitions.h"


I'm unsure which version of Luau I should target for the first EmbeddedBuiltinDefinitions generator:

0.710 (SLua current)

0.723 (Luau latest)

something else

Mostly it depends on how soon you plan to merge Luau:

0.710 has all the data in slua_definitions.yaml already

0.723 is missing data for the integer library, class library, and read-only indicators

I've gone ahead and targeted Luau 0.729 for EmbeddedBuiltinDefinitions.cpp: #181
I made the following Luau update PR's in preparation:

Luau 0.711 math constants #80

Luau 0.711 const keyword #95

Luau 0.713 Magic pcall #178

Luau 0.715 read-only extern properties #165

Luau 0.715 integer library #176

Luau 0.724 class library #179

tapple · 2026-07-13T16:18:59Z

@@ -0,0 +1,523 @@
+// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
+#include "Luau/BuiltinDefinitions.h"


I'm also curious if you want me to put an EmbeddedBuiltinDefinitions.cpp generator here or in the slua repo. I know you had opinions on Rider making the dict wrappers here vs slua repo. I'll put it in lsl-definitions repo unless you say otherwise. It can be moved later if needed

I generate the wrappers here and include them in the actual simulator since putting them into the VM would require a new VM every time we added a flag to any function. (I have the same opinion about prim params, but it is not a hill I'm willing to die on.)

We provide the generators, and the pregenerated .cpp files in the distribution so 3rd parties can include them easily.

tapple · 2026-07-13T22:23:02Z

+    with io.StringIO() as defs:
+        slua_definitions.modules["buffer"].write_luau_def(defs)
+        inserts["BUFFER_TABLE_NOINTEGER"] = defs.getvalue()
+    with io.StringIO() as defs:
+        slua_definitions.modules.pop("buffer").write_luau_def(defs, enable_fflags=True)
+        inserts["BUFFER_TABLE"] = defs.getvalue()


yunno, it's not really sustainable trying to generate 2 different versions of a definition for different FFlags.

I think a better idea would be to:

Only generate the parts of EmbeddedBuiltinDefinitions.cpp that SLua actually enables with it's released FFlag set

Leave the FFlag-disabled parts of EmbeddedBuiltinDefinitions.cpp in the template, to be synced upstream from Luau

In practice, for Luau 0.729, this would mean:

generating kBuiltinDefinitionBufferSrc_NOINTEGER

NOT generating kBuiltinDefinitionBufferSrc

NOT generating kBuiltinDefinitionIntegerSrc

NOT generating kBuiltinDefinitionClassSrc

Removing Luau 0.715 integer library #176, Luau 0.724 class library #179, and Exclude integer and class from generated files #180 as dependencies on this PR

Closing Exclude integer and class from generated files #180 because it's no longer needed (it's what implements enable_fflags in the commented code)

Leaving Luau 0.715 integer library #176 and Luau 0.724 class library #179 unmerged until they are actually enabled via FFlags in SLua, and not just present and disabled in the code

This would also mean that I don't need to ask Harold not to base SLua on a particular Luau version just because of what FFlags Luau happened to put in EmbeddedBuiltinDefinitions.cpp that week (see above comment #181 (comment))

tapple · 2026-07-22T16:55:44Z

 $CMD $DEFS gen_lexer_file ./templates/indra.in.l "$outdir/templated/indra.l"
 $CMD $DEFS gen_parser_file ./templates/indra.in.y "$outdir/templated/indra.y"
 $CMD $DEFS gen_mono_library_defs ./templates/LslLibrary.cs "$outdir/templated/LslLibrary.cs"
+$CMD $DEFS gen_slua_embedded_defs ./templates/EmbeddedBuiltinDefinitions.in.cpp $SLUA "$outdir/cpp/EmbeddedBuiltinDefinitions.cpp"


I may close this PR as lute just gained definitions-loading capabilities, and that sounds more sustainable than this approach: lute check: Support loading definition files luau-lang/lute#1234

tapple changed the title ~~Add generator for EmbeddedBuiltinDefinitions.cpp~~ Generate EmbeddedBuiltinDefinitions.cpp Jul 11, 2026

tapple force-pushed the EmbeddedBuiltinDefinitions.cpp branch from 12e0b16 to dc734fe Compare July 11, 2026 23:04

This was referenced Jul 11, 2026

Luau 0.715 integer library #176

Open

Luau 0.724 class library #179

Draft

Convert Lua's python data structure from list to dict #161

Merged

Diff of generated EmbeddedBuiltinDefinitions.cpp against slua 0.729 tapple/lsl-definitions#3

Open

tapple force-pushed the EmbeddedBuiltinDefinitions.cpp branch from 2b9784f to f8a351c Compare July 13, 2026 15:14

tapple commented Jul 13, 2026

View reviewed changes

tapple force-pushed the EmbeddedBuiltinDefinitions.cpp branch from 71f52cc to 43e169c Compare July 13, 2026 22:10

tapple commented Jul 13, 2026

View reviewed changes

tapple force-pushed the EmbeddedBuiltinDefinitions.cpp branch 2 times, most recently from 5c5861a to e62823d Compare July 14, 2026 00:42

tapple added 12 commits July 20, 2026 14:40

Copy EmbeddedBuiltinDefinitions.cpp from slua 0.710.9

671bcab

Copy EmbeddedBuiltinDefinitions.cpp from slua 0.729

b6025bb

generate global functions

0e967b0

generate bit32 table

225d850

generate math table

373ca1d

generate os table

d326096

generate coroutine, table, dobug, utf8 tables

2b7db59

generate buffer table

84472b9

Don't generate integer definitions

416ca40

generate vector table

124ca25

generate quaternion and uuid tables

de8e14f

generate ll tables

2ed3d9e

tapple force-pushed the EmbeddedBuiltinDefinitions.cpp branch from 3234f9b to 2ed3d9e Compare July 20, 2026 21:40

tapple commented Jul 22, 2026

View reviewed changes

Navigation Menu

Uh oh!

Generate `EmbeddedBuiltinDefinitions.cpp` - #181

Generate `EmbeddedBuiltinDefinitions.cpp`#181
tapple wants to merge 12 commits into
secondlife:mainfrom
tapple:EmbeddedBuiltinDefinitions.cpp

tapple commented Jul 11, 2026 •

edited

Loading

Uh oh!

tapple Jul 13, 2026 •

edited

Loading

Uh oh!

tapple Jul 13, 2026

Uh oh!

tapple Jul 13, 2026

Uh oh!

tapple Jul 13, 2026

Uh oh!

tapple Jul 13, 2026

Uh oh!

Rider-Linden Jul 13, 2026

Uh oh!

tapple Jul 13, 2026 •

edited

Loading

Uh oh!

tapple Jul 22, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

		@@ -0,0 +1,523 @@
		// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
		#include "Luau/BuiltinDefinitions.h"

Uh oh!

Conversation

tapple commented Jul 11, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

tapple Jul 13, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

tapple Jul 13, 2026

Choose a reason for hiding this comment

Uh oh!

tapple Jul 13, 2026

Choose a reason for hiding this comment

Uh oh!

tapple Jul 13, 2026

Choose a reason for hiding this comment

Uh oh!

tapple Jul 13, 2026

Choose a reason for hiding this comment

Uh oh!

Rider-Linden Jul 13, 2026

Choose a reason for hiding this comment

Uh oh!

tapple Jul 13, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

tapple Jul 22, 2026

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

tapple commented Jul 11, 2026 •

edited

Loading

tapple Jul 13, 2026 •

edited

Loading

tapple Jul 13, 2026 •

edited

Loading