Tooling

VS Code Extension

The vscode-seen/ directory contains the official VS Code extension. It tracks the shipped six-language set: en, ar, es, ru, zh, and ja.

Installation From Source

cd vscode-seen
npm install
npm run package
code --install-extension seen-*.vsix

Features

TextMate syntax highlighting for Seen syntax, comments, annotations, package imports, module aliases, facade component syntax, effects, hot reload helpers, and multilingual keywords.

LSP-backed diagnostics, completions, hover, definitions, references, rename, and document symbols through seen lsp.

Import-block folding for contiguous top-level import, use, and pub import declarations.

Build/check/run/package tasks using the shipped seen compile, seen check, seen run, and seen pkg commands.

Snippets for functions, classes, structs, enums, traits/interfaces, effects, packages, facade components, UI state/effects, shared modules, hot reload, GPU/SIMD, defer/errdefer, and FFI.

Commands

Command	Typical CLI
Seen: Build Project	`seen compile <file> [output]`
Seen: Run Project	`seen run <file>`
Seen: Check Project	`seen check <file>`
Seen: Compile Shared Module Objects	`seen compile ... --pic --object-manifest <path>`
Seen: Package Fetch	`seen pkg fetch`
Seen: Package Pack	`seen pkg pack`
Seen: Package Prebuild	`seen pkg prebuild`
Seen: Package Publish	`seen pkg publish` (authorized internal publishing)
Seen: Translate to Another Language	`seen translate <file> --from <lang> --to <lang>`

Extension-only commands such as update checks or visual helpers are editor UI features; compiler behavior remains controlled by the seen CLI.

The official development registry uses its embedded root and serves live public TUF metadata and catalog reads. Custom registries still require an out-of-band root. Authorized internal publishes remain delayed, unavailable, and invisible to resolution. Hosted login, private-package access, yanking, and reporting are inactive, and the production registry is absent.

Configuration

{
  "seen.compiler.path": "seen",
  "seen.lsp.enabled": true,
  "seen.lsp.trace.server": "off",
  "seen.formatting.enable": true,
  "seen.target.default": "native",
  "seen.compile.pic": false,
  "seen.compile.objectManifest": "",
  "seen.language.default": "en"
}

Language Server Protocol

Start the built-in language server:

seen lsp

The server resolves project language from nearby Seen.toml when possible and falls back to English. It masks /// ... /// block comments for source-symbol operations and supports completions/hover for packages, annotations, effects, capabilities, hot reload, imports, sealed classes, exports, new collection and memory types, and stdlib modules.

Neovim

require'lspconfig'.seen.setup{
  cmd = {"seen", "lsp"},
  filetypes = {"seen"},
  root_dir = require'lspconfig.util'.root_pattern("Seen.toml", ".git"),
}

Emacs

(lsp-register-client
 (make-lsp-client :new-connection (lsp-stdio-connection '("seen" "lsp"))
                  :major-modes '(seen-mode)
                  :server-id 'seen-lsp))

Diagnostics and Checks

Use the shipped checker for frontend/type diagnostics:

seen check src/main.seen

Use deterministic mode when auditing reproducibility-sensitive code:

seen check src/main.seen --profile deterministic

The checker and LSP surface warning diagnostics for conservative dead-code cases, including unreachable statements, unused locals or parameters, unused private top-level functions, and unused imports. Warning codes are reported as warnings in editor clients rather than promoted to errors.

Debugging Compiler Output

Useful environment-variable tracing:

SEEN_DEBUG_TYPES=1 seen compile program.seen program
SEEN_TRACE_LLVM=all seen compile program.seen program
SEEN_TRACE_LLVM=gep seen compile program.seen program

LLVM and compile-database emission are compile flags:

seen compile program.seen program --emit-llvm
seen compile program.seen program --emit-compile-db

Linux ARM64 Cross Sysroot

On pacman-compatible Linux hosts, create a local AArch64 cross sysroot without installing system packages globally:

./scripts/setup_linux_arm64_sysroot.sh
source artifacts/toolchains/linux-arm64/env.sh

The helper downloads and extracts cross-packages under artifacts/toolchains/linux-arm64/. The generated env.sh sets SEEN_LINUX_ARM64_SYSROOT and SEEN_LINUX_ARM64_GCC_TOOLCHAIN.

Validate the setup:

bash scripts/native_target_smoke.sh --compiler compiler_seen/target/seen --target linux-arm64
bash scripts/platform_matrix.sh --stage3 compiler_seen/target/seen --platform linux-arm64

Linux RISC-V Cross Sysroot and QEMU

Seen supports linux-riscv64 as an RV64GC Linux GNU userspace target. The canonical target list and triples are documented in Compilation Targets. On pacman-compatible Linux hosts, install system packages directly or create a local sysroot:

sudo pacman -Syu --needed clang llvm lld file qemu-user qemu-user-static qemu-system-riscv qemu-system-riscv-firmware riscv64-linux-gnu-binutils riscv64-linux-gnu-gcc riscv64-linux-gnu-glibc

# Optional local sysroot instead of relying on /usr/riscv64-linux-gnu:
./scripts/setup_linux_riscv64_sysroot.sh
source artifacts/toolchains/linux-riscv64/env.sh

Validate the fast emulator tier with QEMU user-mode:

bash scripts/test_riscv64_qemu.sh --compiler compiler_seen/target/seen --require
bash scripts/native_target_smoke.sh --compiler compiler_seen/target/seen --target linux-riscv64

For full guest validation, provide a RISC-V Linux kernel/rootfs with SSH and run:

SEEN_RISCV64_QEMU_KERNEL=/path/to/Image \
SEEN_RISCV64_QEMU_ROOTFS=/path/to/rootfs.qcow2 \
SEEN_RISCV64_QEMU_IDENTITY=/path/to/key \
bash scripts/test_riscv64_system_qemu.sh --compiler compiler_seen/target/seen --require