Stdlib module io/host_runtime.vitl

Overview

`io/host_runtime.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.

• Medium procedure surface: this file groups several related operations behind one namespace.
• 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 5 of 8 in the io family when ordered by path. By procedure count it ranks 6, and by line count it ranks 6. 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 18 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.

• proc host_runtime_available() -> bool { (line 22)
• proc host_read_file(path: string) -> string { (line 26)
• proc host_write_file(path: string, content: string) -> int { (line 30)
• proc host_append_file(path: string, content: string) -> int { (line 34)
• proc host_file_exists(path: string) -> bool { (line 38)
• proc host_is_file(path: string) -> bool { (line 42)
• proc host_is_directory(path: string) -> bool { (line 46)
• proc host_mkdir_all(path: string) -> int { (line 50)
• proc host_delete_file(path: string) -> int { (line 54)
• proc host_copy_file(src: string, dst: string) -> int { (line 58)
• proc host_move_file(src: string, dst: string) -> int { (line 62)
• proc host_delete_directory(path: string) -> int { (line 66)
• proc host_list_directory(path: string) -> [string] { (line 70)
• proc host_system(command: string) -> int { (line 74)
• proc host_emit_llvm_object(ir_text: string, object_path: string) -> int { (line 78)
• proc host_link_executable(object_path: string, executable_path: string) -> int { (line 82)
• proc host_run_executable(executable_path: string) -> int { (line 86)

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/host_runtime.vitl is explicit.
2. Traverse procedures in source order; the early helpers usually explain the naming and numeric conventions used later.
3. 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/io_host_runtime
proc run_example() -> string {
    give "ok"
}

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/host_runtime
// Native host ABI. The runtime_c implementation is linked into native tools.
intrinsic vitte_host_runtime_available() -> bool;
intrinsic vitte_host_read_file(path: string) -> string;
intrinsic vitte_host_write_file(path: string, content: string) -> int;
intrinsic vitte_host_append_file(path: string, content: string) -> int;
intrinsic vitte_host_file_exists(path: string) -> bool;
intrinsic vitte_host_is_file(path: string) -> bool;
intrinsic vitte_host_is_directory(path: string) -> bool;
intrinsic vitte_host_mkdir_all(path: string) -> int;

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/io/host_runtime
• Line 22: proc host_runtime_available() -> bool {
• Line 26: proc host_read_file(path: string) -> string {
• Line 30: proc host_write_file(path: string, content: string) -> int {
• Line 34: proc host_append_file(path: string, content: string) -> int {
• Line 38: proc host_file_exists(path: string) -> bool {
• Line 42: proc host_is_file(path: string) -> bool {
• Line 46: proc host_is_directory(path: string) -> bool {

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.

Procedures

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/host_runtime.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/io.vitl
• io/stdio.vitl
• io/stream.vitl
• io.vitl