Will Anderson
132 lines
4.8 KiB
Markdown
132 lines
4.8 KiB
Markdown
# El Language — Agent Guide
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El is a self-hosting, statically-typed language that compiles to C. This file orients agents that work on El itself or on programs written in El.
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---
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## What El Is
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El compiles `.el` source → C → native binary. Every El value is `el_val_t` (int64_t). Strings are heap pointers cast through int64_t. The compiler is written in El (self-hosting).
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**The compiler pipeline:**
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```
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elc-cli.el
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└─ imports: compiler.el
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└─ imports: lexer.el, parser.el, codegen.el, codegen-js.el
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```
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The canonical compiler binary is `dist/platform/elc`. It was produced by running an earlier version of itself on `elc-cli.el`.
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---
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## The Two Layers — Know Which One You're In
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### Layer 1: El programs (`.el` files)
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This is where almost all work belongs. El programs are source files that get compiled by `elc`. New library functions, application logic, and language-level utilities all go here as `.el` files.
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**Do not add C code when El can express it.** If functionality can be built from existing El primitives (string ops, `exec`, `fs_read/write`, `http_post`, etc.), write it in El.
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### Layer 2: The C seed (`el-compiler/runtime/el_seed.c`)
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This is the self-contained C OS-boundary layer. It provides the `__`-prefixed primitives that compiled El programs call: libcurl HTTP, pthreads, filesystem I/O, arena allocation, etc. It is **not generated** — it is maintained by hand.
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The old `el_runtime.c` has been archived to `el-compiler/runtime/legacy/`. The runtime is now native El (`runtime/*.el`). `el_seed.c` replaces `el_runtime.c` as the sole C compilation dependency.
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**Only edit `el_seed.c` when you genuinely need OS-level access** (raw sockets, GPU calls, new libcurl features). For everything else, write El.
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When you do add a C builtin:
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1. Add the C function to `el_seed.c`
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2. Declare it in `el_seed.h`
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3. Add it to the `builtin_arity` table in `el-compiler/src/codegen.el` (so the compiler knows the arg count)
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4. Rebuild the elc binary (see below)
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---
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## Rebuilding the Compiler
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After changing any `.el` source in `el-compiler/src/`:
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```bash
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cd /Users/will/Development/neuron-technologies/foundation/el
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./dist/platform/elc elc-cli.el > elc-new.c
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cc -std=c11 -I el-compiler/runtime -lcurl -lpthread \
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-o dist/platform/elc-new \
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elc-new.c el-compiler/runtime/el_seed.c
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# Verify self-hosting:
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./dist/platform/elc-new elc-cli.el > elc-verify.c
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diff elc-new.c elc-verify.c # should be identical
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mv dist/platform/elc-new dist/platform/elc
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```
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After changing `el_seed.c` only (no El source changes), rebuild downstream programs but do NOT need to rebuild the compiler binary itself — the seed is linked at the application level, not the compiler level.
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---
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## How El Programs Are Built
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Each El application has a `build.sh` that:
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1. Concatenates all `.el` source files (stripping `import` lines)
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2. Runs `elc` to produce a `.c` file
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3. Runs `cc` linking against `el_seed.c`
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Example (cgi-studio daemon):
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```bash
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cd products/cgi-studio/el-daemon
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./build.sh
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```
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When you add a new `.el` file to an application, add it to that application's `build.sh` concat list.
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---
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## Parallelism in El
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El is single-threaded at the application level. Parallelism is achieved through subprocess fan-out:
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```el
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// Pattern: write payloads to temp files, exec bash script with & and wait,
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// read results back from temp files.
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fn http_post_parallel(urls: [String], bodies: [String]) -> [String] {
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// ... bash fan-out via exec() ...
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}
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```
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Use `exec()` (blocking) or `exec_bg()` (fire-and-forget) with shell scripts to run concurrent work. There is no goroutine or async/await — parallelism goes through the OS process layer.
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---
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## Key Files
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| Path | What it is |
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|------|-----------|
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| `dist/platform/elc` | Canonical compiler binary (arm64 Mac) |
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| `el-compiler/src/codegen.el` | Code generator — builtin arity table lives here |
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| `el-compiler/src/lexer.el` | Lexer |
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| `el-compiler/src/parser.el` | Parser |
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| `el-compiler/runtime/el_seed.c` | Self-contained C OS-boundary layer (replaces el_runtime.c) |
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| `el-compiler/runtime/el_seed.h` | Seed header (C function declarations) |
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| `spec/language.md` | Language specification |
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| `BOOTSTRAP.md` | How to recover the compiler from scratch |
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| `elc-cli.el` | Compiler entry point |
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| `elc-combined.el` | Pre-merged single-file compiler (used during early bootstrap) |
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---
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## HTTP Timeout
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The El HTTP client (libcurl) defaults to **60 seconds**. Override per-process via `EL_HTTP_TIMEOUT_MS` env var. Set it before spawning any subprocess that makes long API calls:
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```el
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exec("EL_HTTP_TIMEOUT_MS=300000 " + SOME_BIN + " " + args + " 2>&1")
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```
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---
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## Rules
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- New library functions → write in El
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- New OS/hardware primitives → write in C and register in `codegen.el` arity table
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- Never edit `dist/platform/elc` directly — always rebuild from source
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- Never modify `el_seed.c` to add functionality that El can express
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