Stdlib module ffi/abi.vitl

Overview

`ffi/abi.vitl` is a public stdlib surface inside the `ffi` family. It should be read as one focused slice of the broader family responsibility: ABI and foreign-function boundaries used when Vitte code must cross language or runtime edges.

Purpose

This file should be chosen because of responsibility, not because its name “sounds close enough”. Inside the ffi family, it carries one focused part of the contract and keeps that responsibility separate from neighboring concerns.

• A system integration module can expose a narrow ABI-facing wrapper while the rest of the program stays pure.
• A runtime boundary should say exactly when the library stops and the foreign surface begins.

Taxonomy

Think of this page as a generated encyclopedia entry rather than a hand-written tutorial. The goal is to show what kind of module this is, how dense it is, and what reading strategy makes sense before depending on it.

• Large algorithm surface: this file exposes many procedures and likely acts as a domain toolkit rather than a single thin wrapper.
• Owns domain vocabulary: the module declares data shapes in addition to executable helpers, so its types are part of the contract.
• Minimal top-level dependencies: the module reads as mostly self-contained from its opening declarations.

Implementation profile

This profile is inferred directly from the source text. It does not replace reading the file, but it tells you quickly whether the module is mostly declarative, loop-heavy, branch-heavy, or organized around many small exits.

Top-level API inventory

Imported surfaces

This file does not advertise a top-level `use` surface in its opening declarations. That often means it is either self-contained or an aggregation layer.

Position in family

This file is module 1 of 2 in the ffi family when ordered by path. By procedure count it ranks 1, and by line count it ranks 1. Those ranks are useful as rough signals of breadth, not as quality judgments.

Declaration map

The declaration map turns raw source into a scan-friendly catalog. It is useful when the file is large enough that a reader wants to orient by kinds of surfaces first.

The table is exhaustive for top-level declarations of the selected kinds. This file declares 39 matching surfaces.

Representative signatures

These signatures are shown in source order so the page keeps the feel of a reference manual, not just a keyword cloud.

• form TypeLayout { (line 6)
• form FieldLayout { (line 13)
• proc c_type_sizes() -> [int] { (line 21)
• proc vitte_to_c_type(vitte_type: string) -> string { (line 41)
• proc type_size(type_name: string) -> int { (line 62)
• proc type_alignment(type_name: string) -> int { (line 113)
• proc calculate_struct_layout(struct_name: string, field_names: [string], field_types: [string]) -> TypeLayout { (line 119)
• proc struct_field_offset(layout: TypeLayout, field_name: string) -> int { (line 173)
• form CallingConvention { (line 187)
• form ABIProfile { (line 195)
• proc calling_conv_sysv_x64() -> CallingConvention { (line 209)
• proc calling_conv_microsoft_x64() -> CallingConvention { (line 222)
• proc calling_conv_aapcs_arm64() -> CallingConvention { (line 235)
• proc calling_conv_riscv64_lp64d() -> CallingConvention { (line 248)
• proc calling_conv_for_platform(os_name: string, arch: string) -> CallingConvention { (line 261)
• proc abi_profile_linux_x86_64() -> ABIProfile { (line 284)
• proc abi_profile_linux_arm64() -> ABIProfile { (line 299)
• proc abi_profile_linux_riscv64() -> ABIProfile { (line 314)

The list is intentionally capped here; the source file declares 38 matching signatures in total.

How to use this module

Start by reading the file as an ownership boundary. Ask three questions: what enters this module, what stable types or procedures it exports, and what adjacent module should stay outside of it.

1. Read space and top-level imports first so the ownership boundary of ffi/abi.vitl is explicit.
2. Read declared forms and picks before algorithms so the data vocabulary is stable in your head.
3. Traverse procedures in source order; the early helpers usually explain the naming and numeric conventions used later.
4. Only after that compare neighbor modules, because the right boundary choice matters more than memorizing one helper name.

User example

This example is generated from the actual stdlib module surface. Its job is not to be the smallest snippet possible; its job is to show a realistic consumer-shaped file that exercises the module and mirrors the language keywords the module itself relies on.

space demo/ffi_abi
form UserReport {
  label: string,
  ready: bool
}
proc run_example() -> UserReport {
  let entries = c_type_sizes()
  let ready: bool = abi_profile_valid(ABIProfile())
  let failed: bool = false
  let stable: bool = ready and true
  let fallback: bool = ready or false
  let idx: int = 0
  let count: int = 0
  while idx < entries.len {
    set count = count + 1
    set idx = idx + 1
  }
  for sample in [1] {
    let seen: int = sample
  }
  if not ready {
    give UserReport { label: "not-ready", ready: false }
  }
    give UserReport { label: "ok", ready: true }
}

Keyword coverage

This table makes the “all keywords of the module” requirement auditable. It compares the detected Vitte keywords in the source file with the generated consumer example above.

Keywords still not exercised directly in the generated snippet: at. The page still lists them here so the gap is visible.

Source shape

space vitte/stdlib/ffi/abi
// ABI - Application Binary Interface
// Specifies memory layout and type compatibility
form TypeLayout {
  type_name: string,
  size_bytes: int,
  alignment: int,
  fields: [FieldLayout],
}
form FieldLayout {

The excerpt is not meant to replace the file. It exists to make the module recognizable at first glance, the same way a Wikipedia infobox helps the reader orient before reading the whole article.

Source landmarks

Large files are easier to retain when they have visible landmarks. When the source contains explicit section banners, they are surfaced here; otherwise the first major declarations are used as anchors.

• Line 1: space vitte/stdlib/ffi/abi
• Line 6: form TypeLayout {
• Line 13: form FieldLayout {
• Line 21: proc c_type_sizes() -> [int] {
• Line 41: proc vitte_to_c_type(vitte_type: string) -> string {
• Line 62: proc type_size(type_name: string) -> int {
• Line 113: proc type_alignment(type_name: string) -> int {
• Line 119: proc calculate_struct_layout(struct_name: string, field_names: [string], field_types: [string]) -> TypeLayout {

Source organization

When a file carries its own internal chaptering, those chapters usually reveal the intended reading order better than a flat symbol list. This section reconstructs that organization from the source itself.

Complete API catalog

This catalog is the exhaustive file-level index for the module. It is intentionally closer to a generated encyclopedia appendix than to a tutorial summary.

Data surfaces

Procedures

Integration boundaries

Within ffi, this file should remain focused. If a future helper changes the host boundary, scheduling boundary, or data-shape boundary, it probably belongs in a neighbor module instead of being added here by convenience.

• Family responsibility: ABI and foreign-function boundaries used when Vitte code must cross language or runtime edges.
• Family architecture role: Use `ffi` only when the program really needs a foreign boundary. This family should make coupling visible instead of hiding it.

Composition guidance

Choose this module when

• Choose ffi/abi.vitl when the main question is owned by this module rather than by transport, storage, orchestration, or user-interface code.
• A system integration module can expose a narrow ABI-facing wrapper while the rest of the program stays pure.
• A runtime boundary should say exactly when the library stops and the foreign surface begins.

Pause before extending it when

• Avoid extending this file when the new helper mostly changes the boundary to host I/O, runtime coordination, or foreign integration instead of staying inside ffi.
• Check nearby modules such as ffi/ffi.vitl before adding convenience wrappers here.

Relationship table

This table keeps the page closer to a real encyclopedia entry: a module is easier to understand when compared with its nearest alternatives in the same family.

Neighbor modules

• ffi/ffi.vitl