trealla-prolog/go

Trealla Prolog embedded in Go using WASM

go's Issues

wasm64 support

It's possible to exhaust the memory of the interpreter (4GB) by throwing a ton of concurrent queries at it. Using wasm64 should fix this.

Document / automate build process for Trealla binary

Currently I'm just kind of shoving the modules from lib/ into Trealla and building it. Need to improve this by maybe: automating this process, or including json/toplevel in the main project, or work around this with better consulting.

Move repo to Trealla organization

FYI, I plan on moving this to the @trealla-prolog organization. See discussion here: trealla-prolog/trealla#450 (comment)

Package name will probably become something like github.com/trealla-prolog/go/trealla (or maybe /prolog? 🤔)

Persistent interpreter instances

Currently all queries go through a fresh interpreter. It would be nice to keep them alive so they can keep their knowledge base contents between requests.

I'm not sure how easy it will be because the stdin interfaces for Go WASM libraries don't look so great. Would be really nice to be able to pass an io.Reader to them.
Might be possible to work around by exporting Go/C functions and calling from Trealla FFI (need to add FFI to Trealla WASM first).

What can I do with "too many errors" ?

@guregu hi! ~
could you help me resolve this? just trying go build for stream but getting stopped at these errors. haven't encountered this before. also just updated go version; if that matters. Windows 11.

(sorry for posting here , but idk how else to contact you 😅 )

Interop broken on Linux?

$ WASMTIME_BACKTRACE_DETAILS=1 go test -v ./trealla   
=== RUN   TestInterop/custom_function
2023/07/19 18:29:51 query: interop_test(X).
2023/07/19 18:29:51 query: X is 1 + 1.
=== NAME  TestInterop
    interop_test.go:34: trealla: query error: error while executing at wasm backtrace:
            0: <unknown>!pl_query
            1: 0x1fe1db - fn_sys_host_call_2
                            at /Users/guregu/code/trealla/fork/src/predicates.c:7692:12
            2: 0x234bc6 - start
                            at /Users/guregu/code/trealla/fork/src/query.c:1611:14
            3: 0x23b115 - execute
                            at /Users/guregu/code/trealla/fork/src/query.c:1823:9
            4: 0xf8327 - run
                            at /Users/guregu/code/trealla/fork/src/parser.c:3630:3
            5: 0x223e56 - pl_query
                            at /Users/guregu/code/trealla/fork/src/prolog.c:162:12
        
        Caused by:
            wasm trap: call stack exhausted

Works ok on macOS+arm64 so probably something weird going on. This is running in a VM though.

more prologs, more embedding languages

Cool project! Would you accept contributions to support more Prologs? Or embed in other languages different than Go?

Back in 2019 we created a script to run/install many Prolog systems for the LP/CP programming contest:

https://github.com/lpcp-contest/docker-lpcpsys/blob/master/scripts/build.sh

It builds a docker file but maybe it is not hard to target WASM.

Memory leaks (wasmtime vs wasmer)

Would wasmtime provide any advantage over wasmer?