Stdlib module collections/deque.vitl

Overview

`collections/deque.vitl` is a public stdlib surface inside the `collections` family. It should be read as one focused slice of the broader family responsibility: Container and traversal surfaces such as vector, deque, queue, stack, linked list, hashmap, hashset, graph, and matrix.

Purpose

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

• Use this module when ordered storage and traversal cost are more important than host-facing effects.
• A build report groups diagnostics in a vector and indexes them in a hashmap.
• A scheduler stores pending work in a queue or deque.
• A graph or matrix page should explain why those shapes exist, not just list filenames.

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 3 of 11 in the collections family when ordered by path. By procedure count it ranks 10, and by line count it ranks 11. 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 11 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 push_front() -> int { (line 9)
• proc push_back() -> int { (line 13)
• proc pop_front() -> int { (line 17)
• proc pop_back() -> int { (line 21)
• proc peek_front() -> int { (line 25)
• proc peek_back() -> int { (line 29)
• proc is_empty() -> int { (line 33)
• proc size() -> int { (line 37)
• proc rotate_left() -> int { (line 41)
• proc rotate_right() -> int { (line 45)

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 collections/deque.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/collections_deque
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_checked/collections_deque
proc push_front() -> int {
  give 0
}
proc push_back() -> int {
  give 0
}
proc pop_front() -> int {
  give 0
}

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_checked/collections_deque
• Line 9: proc push_front() -> int {
• Line 13: proc push_back() -> int {
• Line 17: proc pop_front() -> int {
• Line 21: proc pop_back() -> int {
• Line 25: proc peek_front() -> int {
• Line 29: proc peek_back() -> int {
• Line 33: proc is_empty() -> int {

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 collections, 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: Container and traversal surfaces such as vector, deque, queue, stack, linked list, hashmap, hashset, graph, and matrix.
• Family architecture role: Use `collections` when the shape of data matters more than the host system. This family owns grouping, ordering, indexing, and traversal concerns.

Composition guidance

Choose this module when

• Choose collections/deque.vitl when the main question is owned by this module rather than by transport, storage, orchestration, or user-interface code.
• Use this module when ordered storage and traversal cost are more important than host-facing effects.
• A build report groups diagnostics in a vector and indexes them in a hashmap.
• A scheduler stores pending work in a queue or deque.
• A graph or matrix page should explain why those shapes exist, not just list filenames.

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 collections.
• Check nearby modules such as collections/collections.vitl, collections/graph.vitl, collections/hashmap.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

• collections/collections.vitl
• collections/graph.vitl
• collections/hashmap.vitl
• collections/hashset.vitl
• collections/linkedlist.vitl
• collections/matrix.vitl
• collections/queue.vitl
• collections/stack.vitl