Stdlib module io.vitl

Overview

`io.vitl` is a public stdlib surface inside the `io` family. It should be read as one focused slice of the broader family responsibility: File, buffer, stream, stdio, and host-runtime access helpers.

Purpose

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

• A manifest is loaded through `io`, parsed elsewhere, validated elsewhere, and only then emitted back through `io`.
• A stdio helper should explain where user-facing text enters the flow.

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.
• Has tuning constants: part of the module behavior is controlled by named constants that document default precision, limits, or policy.
• Minimal top-level dependencies: the module reads as mostly self-contained from its opening declarations.
• Explicit export surface: the file ends with visible export declarations instead of relying only on implicit namespace discovery.

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 8 in the io 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 173 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.

• const IO_VERSION: string = "1.0.0" (line 11)
• const EOF: int = -1 (line 13)
• const NULL_FD: int = -1 (line 14)
• const SEEK_SET: int = 0 (line 16)
• const SEEK_CUR: int = 1 (line 17)
• const SEEK_END: int = 2 (line 18)
• const IO_READ: int = 1 (line 20)
• const IO_WRITE: int = 2 (line 21)
• const IO_APPEND: int = 4 (line 22)
• const IO_CREATE: int = 8 (line 23)
• const IO_TRUNC: int = 16 (line 24)
• const IO_BINARY: int = 32 (line 25)
• const IO_TEXT: int = 64 (line 26)
• const READ: string = "r" (line 28)
• const WRITE: string = "w" (line 29)
• const APPEND: string = "a" (line 30)
• const READ_WRITE: string = "r+" (line 31)
• const WRITE_READ: string = "w+" (line 32)

The list is intentionally capped here; the source file declares 172 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 io.vitl is explicit.
2. Scan constants before procedures; they often encode precision, limits, or policy assumptions that explain later behavior.
3. Read declared forms and picks before algorithms so the data vocabulary is stable in your head.
4. Traverse procedures in source order; the early helpers usually explain the naming and numeric conventions used later.
5. Use the source landmarks section below as a table of contents when the file is large.

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/io
const SAMPLE_LABEL: string = "demo"
form UserReport {
  label: string,
  ready: bool
}
pick UserOutcome {
  case Ready(message: string)
  case Empty(reason: string)
}
proc run_example() -> UserOutcome {
  let entries = io_modules()
  let ready: bool = file_is_open(File())
  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
  }
  if not ready {
    give UserOutcome.Empty("module not ready")
  } else {
    give UserOutcome.Ready("ok")
  }
  let copies: f64 = 1 as f64
}
export run_example

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.

The generated snippet exercises every detected Vitte keyword used by this module.

Source shape

space vitte/stdlib/io
export *
const IO_VERSION: string = "1.0.0"
const EOF: int = -1
const NULL_FD: int = -1
const SEEK_SET: int = 0
const SEEK_CUR: int = 1
const SEEK_END: int = 2
const IO_READ: int = 1
const IO_WRITE: int = 2

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.

• Vitte I/O Library / C-like stdio + POSIX-like file/path utilities / current Vitte syntax: { }

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.

Constants

Data surfaces

Procedures

Exports

Integration boundaries

Within io, 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: File, buffer, stream, stdio, and host-runtime access helpers.
• Family architecture role: Use `io` when the program must read or write bytes, files, or streams. Keep it separate from validation, parsing, or business decisions.

Composition guidance

Choose this module when

• Choose io.vitl when the main question is owned by this module rather than by transport, storage, orchestration, or user-interface code.
• A manifest is loaded through `io`, parsed elsewhere, validated elsewhere, and only then emitted back through `io`.
• A stdio helper should explain where user-facing text enters the flow.

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 io.
• Check nearby modules such as io/buffer.vitl, io/file.vitl, io/fileops.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

• io/buffer.vitl
• io/file.vitl
• io/fileops.vitl
• io/host_runtime.vitl
• io/io.vitl
• io/stdio.vitl
• io/stream.vitl