[IvanK_net]

I did not find anything interesting or useful in this article.

Author just says, that OpenGL and "shaders as strings" are bad, without explaining why. Then author speaks about some mysterious "Heterogeneity" without specifying what it means.

"We need programming models that let us write one program that spans multiple execution contexts" - what does it mean? How should that model look like, how should it be different? It is like saying "cars with 4 wheels are bad, cars with different number of wheels would be better".

[viraptor]

I thought the problem is pretty much spelled out in that post:

> [...] doesn’t solve the fundamental problem: the interface between the CPU and GPU code is needlessly dynamic, so you can’t reason statically about the whole, heterogeneous program.

It's the same thing as raw SQL vs abstraction (could be ORM, but not necessarily). Not only are your assumptions not verified (is there table X, will I receive the columns I expect, etc.), you cannot tell if the constructs are even valid until runtime (is "SELECT %s from %s" valid?). Abstractions let you do things like `table.where(abc=123)` which is guaranteed to be a valid construct and can be verified against schema at compile time. It can still fail at runtime, but has much fewer failure modes and is clearer when reading.

[rwmj]

10 years ago I wrote a thing called PG'OCaml which integrates OCaml and SQL in a type safe way. You write code like:

    PGSQL(dbh) "insert into employees (name, salary, email)
                values ($name, $salary, $?email)"

and it (at compile time) creates the correct PREPARE+EXECUTE pair and checks types across the languages. (It's not obvious but it is also free of SQL injections.)

For example if your OCaml 'salary' variable was a string but the column is an int then the above program wouldn't compile. If you change the type of the db column after compiling the program then you get a runtime error instead.

Still around although now maintained by a group of authors: http://pgocaml.forge.ocamlcore.org/ (git source: https://github.com/darioteixeira/pgocaml)

It's only possible because OCaml has real macros. It wouldn't be easy to do this in C/C++ (I guess? - maybe with an LLVM-based pre-processing parser or something)

[fauigerzigerk]

This used to be how a lot of SQL code was written. I think it's about as old as SQL itself. See Oracle's Pro*C for instance. It's a C precompiler that generates API calls and optionally does type checking. There's even an ANSI/ISO standard for embedded SQL.

[chiph]

Yep. I used to use the Sybase SQL precompiler in OS/2 with Watcom C++. Nullable columns were a pain because you had to define a separate boolean variable to hold the null status for each one.

[Scramblejams]

Just last night I was thinking about what it would look like to have a language that would type check your SQL strings. Thanks for sharing PG'OCaml!

[awinter-py]

totally right about the parallel with SQL.

This paper is from a few years ago about verifying programs that span multiple languages / runtimes:

http://www.ccs.neu.edu/home/amal/papers/verifcomp.pdf

We need to get these concepts into mainstream tools. SQL certainly seems to be the low-hanging fruit (simple, straightfoward typing, widely used and understood, frequent errors lead to security problems).

[fixermark]

I think the author of the article may be failing to understand why the dynamism is there. It's, unfortunately, not needless.

The shader API is an API where the developer provides source code at runtime and then modifies inputs to the program compiled from the source code that runs on the user's GPU. It's a source-code level interface because it makes nearly zero assumptions about what capabilities the underlying hardware will have; interpretation and compilation of the source is left largely up to the vendor (literally, in the sense that the compiler is part of the GPU's driver kit and not part of the OpenGL library---an issue that has caused me HOURS of headache when encountering a bug in a closed-source graphics card's compiler, let me tell ya ;) ).

I strongly suspect a more compile-time-checkable API would lack the flexibility needed to capture all shader behavior---both when the API was codified and in the future. It's a pain in the ass to use, but I'm not convinced it's avoidable pain.

[marssaxman]

Yes, that is the problem: the compiler is embedded in the GPU driver. We can't do better because we can't build our own compilers.

[pjc50]

Communication between the part of the program that runs on the CPU and the part that runs on the GPU is typeless and requires manually marshalling arguments. Javascript programmers will shrug at this, but for people used to strong type checking and better automarshalling of RPC it's very disappointing.

[fixermark]

As a fun exercise, try sketching out what a stronger-typed API for shaders and shader parameters would look like.

It's a useful exercise in understanding why such a thing wasn't done.