Compiler¶

The Fourier compiler lives at fourier/ in the source tree. It's a single Python package with one public entry point:

from fourier import compile_source

bytecode: bytes = compile_source(source_text)

That's the whole API surface. Everything else is internal.

Pipeline¶

.fou source text
      │
      │   tokenize()                  fourier/lexer.py
      ▼
list[Token]
      │
      │   parse()                     fourier/parser.py
      ▼
Contract AST
      │
      │   compile_contract()          fourier/codegen.py
      ▼
list of (op, arg) tuples + labels
      │
      │   assemble()                  vm/asm.py
      ▼
bytecode (bytes)

No optimizer, no IR, no register allocator. Each statement compiles to a fixed bytecode template.

Stage summary¶

Stage	Input	Output	Errors raised
Lex	source string	`list[Token]`	`LexError` (unexpected char, empty hex literal)
Parse	tokens	`Contract` AST	`ParseError` (expected X got Y, etc.)
Codegen	AST	assembly items	`CompileError` (unknown identifier, slot collision, type mismatch, etc.)
Assemble	items	bytecode	`ValueError` (PUSH out of range, unknown asm item)

See Error reference for the catalog of error messages each stage can produce.

CLI¶

There is no standalone CLI in v1. You compile from Python:

from fourier import compile_source

with open("counter.fou") as f:
    src = f.read()

bytecode = compile_source(src)

with open("counter.bin", "wb") as f:
    f.write(bytecode)

A standalone fourierc binary is on the follow-up list. Until it lands, use the python -c '…' one-liners on the CLI usage page — they're terminal-friendly and produce identical bytecode.

Subpages¶

CLI usage — how to compile a .fou file without writing Python
Python API — compile_source, plus the internal hooks if you need lex/parse/codegen access
Error reference — every error message the compiler can produce, with cause and fix