nightshade/mach_examples
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
Files
109a2562680d907d01503f38d6f24d1cc31990df
mach_examples/llms-full.txt

1326 lines
48 KiB
Plaintext
Raw Normal View History

MaCH repo
2025-07-24 12:46:01 -05:00
# MACH (Modern Asynchronous C Hypermedia)
Declarative framework for asynchronous, reactive web apps in C23. Below is a tutorial guide that builds a working app step by step, then a complete reference. Every code block is real, compilable code (not pseudo-code).
## Critical rules
- Templates use Mustache **sections**, not dot paths. Open the section first, even for single-row queries: `{{#blog}}{{title}}{{/blog}}`, never `{{blog.title}}` or bare `{{title}}` at root.
- Inline templates are C string literals. Every Mustache tag, including section open/close tags on their own lines, must be inside quotes.
- Modules are composed by `#include "module/module.c"` from `main.c` and listing them in `.modules`. **Never** use `extern` declarations.
- Modules communicate only through pub/sub events (`emit()` + `.publishes` + `.events`). They never call each other directly.
- Resource fields like `.get`, `.url`, `.mime` are not top-level config fields — they belong inside entries of `.resources`.
- Multiple items in a single `query()` or `fetch()` call run **concurrently**. Two back-to-back calls run serially.
- SQL `{{interpolation}}` is bound as prepared-statement parameters. Never spliced.
- `render()` auto-escapes context values. Use `{{raw:field}}` only when the value is trusted HTML.
- Application code never calls `malloc`/`free` and never manages threads. Use `allocate(bytes)` and `defer_free(ptr)` for arena-managed memory inside `exec()`.
---
## Guide
A walkthrough that builds a working todo app in nine steps, introducing one concept at a time.
### 1. A Page
Two resources, each with a GET pipeline. The home page links to the todos page with `{{url:todos}}`, which resolves to the target resource's URL at render time.
```c
#include <mach.h>
config mach(){
return (config) {
.resources = {
{"home", "/",
.get = {
render(.template =
"<html><body>"
"<h1>Welcome</h1>"
"<a href='{{url:todos}}'>My Todos</a>"
"</body></html>"
)
}
},
{"todos", "/todos",
.get = {
render(.template =
"<html><body>"
"<h1>My Todos</h1>"
"<p>Nothing yet.</p>"
"</body></html>"
)
}
}
}
};
}
```
Each resource names itself (`"home"`, `"todos"`) so other pages reference it by name, not hardcoded path.
### 2. Show Data
Add a SQLite database with one migration and one seed, then read from it in the GET pipeline.
```c
#include <mach.h>
#include <sqlite.h>
config mach(){
return (config) {
.resources = {
// ... home resource unchanged from step 1
{"todos", "/todos",
.get = {
query({.set_key = "todos", .db = "todos_db",
.query = "select id, title from todos;"}),
render(.template =
"<html><body>"
"<h1>My Todos</h1>"
"<ul>{{#todos}}<li>{{title}}</li>{{/todos}}</ul>"
"</body></html>"
)
}
}
},
.databases = {{
.engine = sqlite_db,
.name = "todos_db",
.connect = "file:todos.db?mode=rwc",
.migrations = {
"CREATE TABLE todos ("
"id INTEGER PRIMARY KEY AUTOINCREMENT,"
"title TEXT NOT NULL"
");"
},
.seeds = {"INSERT INTO todos(title) VALUES('Learn MACH');"}
}},
.modules = {sqlite}
};
}
```
`query` runs the SELECT and stores the rows under `todos` in pipeline context. `render` walks the section with `{{#todos}}...{{/todos}}`. Migrations run on the first connection.
> **Concurrent queries.** Multiple items in a single `query()` run concurrently. Two separate `query({...})` steps run serially.
> ```c
> query(
> {.set_key = "todos", .db = "todos_db", .query = "select id, title from todos;"},
> {.set_key = "count", .db = "todos_db", .query = "select count(*) as n from todos;"}
> )
> ```
> **Sections, not dot paths.** Write `{{#todos}}{{title}}{{/todos}}`, not `{{todos.title}}`. Same syntax for single-row records: `{{#count}}{{n}}{{/count}}`. Dot paths render empty.
### 3. Accept Input
Add a POST verb that validates a `title` parameter, inserts it, and redirects back to GET (POST-redirect-GET).
```c
config mach(){
return (config) {
.resources = {
// ... home resource unchanged
{"todos", "/todos",
.get = {
// ... unchanged from step 2; template gains a form (see below)
},
.post = {
validate({"title",
.validation = validate_not_empty,
.message = "title cannot be empty"}),
query({.db = "todos_db",
.query = "insert into todos(title) values({{title}});"}),
redirect("todos")
}
}
},
// ... .databases and .modules unchanged from step 2
};
}
```
The GET template gains a form pointing at `{{url:todos}}`:
```c
"<form method='post' action='{{url:todos}}'>"
"<input name='title' value='{{input:title}}'>"
"<button>Add</button>"
"</form>"
```
The POST pipeline validates first; on success, the title is promoted from `input:title` to app scope. Interpolated `{{title}}` is bound as a prepared-statement parameter, not spliced. `redirect("todos")` returns 302 to `/todos`.
### 4. Handle Errors
Validation failure raises `http_bad_request`. Add a resource-scoped error handler that re-enters the GET pipeline with `reroute("todos")`, and add error markup to the form template.
```c
{"todos", "/todos",
.get = {
query({.set_key = "todos", .db = "todos_db",
.query = "select id, title from todos;"}),
render(.template =
"<html><body>"
"<h1>My Todos</h1>"
"<ul>{{#todos}}<li>{{title}}</li>{{/todos}}</ul>"
"<form method='post' action='{{url:todos}}'>"
"<input name='title' value='{{input:title}}'>"
"{{#error:title}}<span>{{error_message:title}}</span>{{/error:title}}"
"<button>Add</button>"
"</form>"
"</body></html>"
)
},
.post = {
// ... unchanged from step 3
},
.errors = {
{http_bad_request, { reroute("todos") }}
}
}
```
`reroute("todos")` re-enters the GET pipeline in-process. The `input:` and `error:` scopes persist across the reroute, so `{{input:title}}` repopulates the field and `{{#error:title}}` renders the message.
### 5. Nested Data
Add a `/todos/:id` page that fetches a todo and its comments concurrently, nests comments inside the todo record, and renders them together. Comments belong to the same domain as todos, so the new `comments` table is added as a migration on the existing `todos_db`.
The todos list also gains links: `<ul>{{#todos}}<li><a href='{{url:todo:id}}'>{{title}}</a></li>{{/todos}}</ul>`.
```c
{"todo", "/todos/:id",
.get = {
validate({"id", .validation = validate_integer,
.message = "must be an integer"}),
query(
{.set_key = "todo", .db = "todos_db",
.query = "select id, title from todos where id = {{id}};"},
{.set_key = "comments", .db = "todos_db",
.query = "select id, todo_id, body from comments where todo_id = {{id}};"}
),
join(
.target_table_key = "todo",
.target_field_key = "id",
.nested_table_key = "comments",
.nested_field_key = "todo_id",
.target_join_field_key = "comments"
),
render(.template =
"<html><body>"
"{{#todo}}"
"<h1>{{title}}</h1>"
"<h2>Comments</h2>"
"<ul>{{#comments}}<li>{{body}}</li>{{/comments}}</ul>"
"{{/todo}}"
"</body></html>"
)
}
}
```
New migration appended to `todos_db.migrations`:
```c
"CREATE TABLE comments ("
"id INTEGER PRIMARY KEY AUTOINCREMENT,"
"todo_id INTEGER NOT NULL REFERENCES todos(id),"
"body TEXT NOT NULL"
");"
```
Two queries run in parallel under one `query()` call. `join()` lifts `comments` inside each todo record. The template enters `{{#todo}}` first and reaches `{{#comments}}` from within. Iterating `{{#comments}}` at root would skip the nesting; dot paths like `{{todo.title}}` do not resolve.
### 6. Tasks
Tasks are named pipelines that run asynchronously on task reactors. Triggered on a cron schedule or enqueued from another pipeline with `task("name")`. Add a nightly task that records the current todo count, and re-run it from POST so stats stay fresh.
```c
config mach(){
return (config) {
.resources = {
// ... home, todo/:id unchanged
{"todos", "/todos",
.get = { /* unchanged from step 4 */ },
.post = {
validate({"title",
.validation = validate_not_empty,
.message = "title cannot be empty"}),
query({.db = "todos_db",
.query = "insert into todos(title) values({{title}});"}),
task("record_daily_stats"),
redirect("todos")
},
.errors = { {http_bad_request, { reroute("todos") }} }
}
},
.tasks = {
{"record_daily_stats", {
query({.db = "todos_db",
.query = "insert into daily_stats(todo_count) "
"select count(*) from todos;"})
}, .cron = "0 0 * * *"}
},
.databases = {{
.engine = sqlite_db,
.name = "todos_db",
.connect = "file:todos.db?mode=rwc",
.migrations = {
// ... existing todos and comments tables, plus:
"CREATE TABLE daily_stats ("
"id INTEGER PRIMARY KEY AUTOINCREMENT,"
"recorded_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,"
"todo_count INTEGER NOT NULL"
");"
},
.seeds = {"INSERT INTO todos(title) VALUES('Learn MACH');"}
}},
.modules = {sqlite}
};
}
```
The same task definition is reused two ways: `.cron` runs it nightly, `task("record_daily_stats")` enqueues it on demand from the POST. Both invocations land on a task reactor, on separate cores from request reactors, so POST returns immediately. If a task needs values from the calling context, list them in `.accepts` and reference inside the task with `{{user_id}}` interpolation.
Tasks are durable: if the process crashes mid-task, MACH checkpoints context after each step and resumes at the step where it left off.
### 7. Modules & Events
Features split into self-contained modules. A module declares its own resources, databases, migrations, context, error/repair handlers, tasks, and event subscribers. Modules communicate through pub/sub events.
Modules are plain C files. Each defines a function returning `config`. `main.c` pulls them in with `#include` and registers in `.modules`.
```
.
├── activity/
│ └── activity.c
├── todos/
│ └── todos.c
└── main.c
```
**`main.c`** — thin root, composes modules and handles cross-cutting concerns.
```c
#include <mach.h>
#include <sqlite.h>
#include "todos/todos.c"
#include "activity/activity.c"
config mach(){
return (config){
.resources = {
{"home", "/",
.get = {
render(.template =
"<html><body>"
"<h1>Welcome</h1>"
"<a href='{{url:todos}}'>My Todos</a> · "
"<a href='{{url:activity}}'>Activity</a>"
"</body></html>"
)
}
}
},
.modules = {todos, activity, sqlite}
};
}
```
**`todos/todos.c`** — the existing todos config from step 6, wrapped as `config todos()` with `.name` and `.publishes`. POST gains `emit("todo_created")`.
```c
#include <mach.h>
#include <sqlite.h>
config todos(){
return (config){
.name = "todos",
.publishes = {
{"todo_created", .with = {"title"}}
},
.resources = {
// ... todos and todo/:id resources from step 6
// POST gains: emit("todo_created") between query() and redirect()
},
.tasks = {
// ... record_daily_stats from step 6
},
.databases = {{
// ... todos_db with todos, comments, daily_stats from step 6
}},
.modules = {sqlite}
};
}
```
**`activity/activity.c`** — new subscriber module with its own database, its own resource, and an event handler.
```c
#include <mach.h>
#include <sqlite.h>
config activity(){
return (config){
.name = "activity",
.resources = {
{"activity", "/activity",
.get = {
query({.set_key = "activities", .db = "activity_db",
.query = "select kind, ref, created_at from activities "
"order by created_at desc;"}),
render(.template =
"<html><body>"
"<h1>Activity</h1>"
"<ul>{{#activities}}"
"<li>{{created_at}}: {{kind}} — {{ref}}</li>"
"{{/activities}}</ul>"
"</body></html>"
)
}
}
},
.events = {
{"todo_created", {
query({.db = "activity_db",
.query = "insert into activities(kind, ref) "
"values('created', {{title}});"})
}}
},
.databases = {{
.engine = sqlite_db,
.name = "activity_db",
.connect = "file:activity.db?mode=rwc",
.migrations = {
"CREATE TABLE activities ("
"id INTEGER PRIMARY KEY AUTOINCREMENT,"
"kind TEXT NOT NULL,"
"ref TEXT NOT NULL,"
"created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP"
");"
}
}},
.modules = {sqlite}
};
}
```
When POST in `todos` calls `emit("todo_created")`, MACH propagates `title` from current context to every subscriber's pipeline. Neither module references the other; they only agree on the event name and payload.
Events are durable. With `.publishes` defined, MACH tracks delivery in a `mach_events` database — undelivered events replay on next boot. Adding a third subscriber is a new file with `.events`; the publisher doesn't change.
### 8. External Assets
Once templates and SQL grow past a few lines, extract them into their own files and load with `(asset){#embed "..."}` in `.context`, then reference by name.
```
.
├── activity/
│ ├── activity.c
│ ├── activity.mustache.html
│ ├── create_activities_table.sql
│ ├── get_activities.sql
│ └── insert_activity.sql
├── static/
│ └── home.mustache.html
├── todos/
│ ├── create_todos_table.sql
│ ├── create_comments_table.sql
│ ├── create_daily_stats_table.sql
│ ├── get_todos.sql
│ ├── create_todo.sql
│ ├── get_todo.sql
│ ├── get_comments.sql
│ ├── record_daily_stats.sql
│ ├── todos.c
│ ├── todos_list.mustache.html
│ └── todo_detail.mustache.html
└── main.c
```
`static/` is not a module (no `.c` file) — it's a plain directory for root-level templates.
**`main.c`** with assets:
```c
#include <mach.h>
#include <sqlite.h>
#include "todos/todos.c"
#include "activity/activity.c"
config mach(){
return (config){
.resources = {
{"home", "/",
.get = {
render("home")
}
}
},
.context = {
{"home", (asset){#embed "static/home.mustache.html"}}
},
.modules = {todos, activity, sqlite}
};
}
```
**`todos/todos.c`** with assets — pipelines reference assets by name; `.context` lists every asset; `.migrations` accept assets directly.
```c
config todos(){
return (config){
.name = "todos",
.publishes = {{"todo_created", .with = {"title"}}},
.resources = {
{"todos", "/todos",
.get = {
query({"get_todos", .set_key = "todos", .db = "todos_db"}),
render("todos_list")
},
.post = {
validate({"title",
.validation = validate_not_empty,
.message = "title cannot be empty"}),
query({"create_todo", .db = "todos_db"}),
task("record_daily_stats"),
emit("todo_created"),
redirect("todos")
},
.errors = {{http_bad_request, { reroute("todos") }}}
},
{"todo", "/todos/:id",
.get = {
validate({"id", .validation = validate_integer,
.message = "must be an integer"}),
query(
{"get_todo", .set_key = "todo", .db = "todos_db"},
{"get_comments", .set_key = "comments", .db = "todos_db"}
),
join(
.target_table_key = "todo",
.target_field_key = "id",
.nested_table_key = "comments",
.nested_field_key = "todo_id",
.target_join_field_key = "comments"
),
render("todo_detail")
}
}
},
.tasks = {
{"record_daily_stats", {
query({"record_daily_stats", .db = "todos_db"})
}, .cron = "0 0 * * *"}
},
.context = {
{"todos_list", (asset){#embed "todos_list.mustache.html"}},
{"todo_detail", (asset){#embed "todo_detail.mustache.html"}},
{"get_todos", (asset){#embed "get_todos.sql"}},
{"create_todo", (asset){#embed "create_todo.sql"}},
{"get_todo", (asset){#embed "get_todo.sql"}},
{"get_comments", (asset){#embed "get_comments.sql"}},
{"record_daily_stats", (asset){#embed "record_daily_stats.sql"}}
},
.databases = {{
.engine = sqlite_db,
.name = "todos_db",
.connect = "file:todos.db?mode=rwc",
.migrations = {
(asset){#embed "create_todos_table.sql"},
(asset){#embed "create_comments_table.sql"},
(asset){#embed "create_daily_stats_table.sql"}
},
.seeds = {"INSERT INTO todos(title) VALUES('Learn MACH');"}
}},
.modules = {sqlite}
};
}
```
`activity/activity.c` follows the same pattern: extract its template and SQL into `activity/`, reference from `.context`.
SQL interpolation (`{{title}}`) still works the same as inline — bound as prepared-statement parameters. Templates are still Mustache (sections, not dot paths). The pipeline shape is unchanged across files; only where the strings live has moved.
### 9. External Data
Pipelines reach external HTTP services with `fetch()`. JSON is parsed into tables and records (nested JSON → nested context tables); plain text stored as a string. Add a quote of the day to the home page.
**`static/home.mustache.html`**
```html
<html><body>
<h1>Welcome</h1>
{{#quote}}
<blockquote>{{content}} — {{author}}</blockquote>
{{/quote}}
<a href='{{url:todos}}'>My Todos</a> · <a href='{{url:activity}}'>Activity</a>
</body></html>
```
**`main.c`**
```c
config mach(){
return (config){
.resources = {
{"home", "/",
.get = {
fetch("https://api.quotable.io/random",
.set_key = "quote"),
render("home")
}
}
},
.context = {
{"home", (asset){#embed "static/home.mustache.html"}}
},
.modules = {todos, activity, sqlite}
};
}
```
The Quotable API returns `{"author": "...", "content": "..."}`. MACH parses it into a single-row table under `quote`. Template opens `{{#quote}}...{{/quote}}` to read fields, same as query results.
Like `query()`, multiple items in a single `fetch()` run concurrently. `fetch()` also supports POST/PUT/PATCH/DELETE, custom headers, JSON or text request bodies, and URLs with `{{interpolation}}`.
---
## Reference
### Notation
C designated initializers at different brace depths:
| Braces | Meaning | Example |
|--------|---------|---------|
| `{}` | Single value or struct | `.get = { ... }` |
| `{{}}` | Array of structs | `.databases = {{ ... }}` |
Multiple array elements: comma-separate inner braces: `.databases = {{...}, {...}}`.
Inside steps, each `{}` initializes one item. Steps that accept multiple items (such as `query` and `validate`) use comma-separated items: `query({...}, {...})`.
> **Fields are only reachable from inside their section.** Templates use Mustache sections, not dot paths. Open the section first, even for single-row queries.
> - ✅ `{{#blog}}{{title}}{{/blog}}` works for single-row or multi-row queries
> - ❌ `{{title}}` at root: no top-level `title` exists
> - ❌ `{{blog.title}}`: dot paths are not supported
### Context
Pipelines read from and write to a shared context: a scoped key-value store living for the duration of a request.
`.context` seeds at the root with variables and assets available on every request. Templates and SQL stored here are referenced by name in `render()`, `query()`, and `find()`. Use `(asset){#embed "file"}` to bake files into the binary at compile time. Docker secrets exposed to the container are available in context.
Three scopes:
- `input:xxx` for raw request parameters
- `error:xxx` for validation/error data
- unprefixed names for app scope (query results, validated inputs, context variables)
`validate()` bridges input to app scope.
```c
.context = {
{"site_name", "MACH App"},
{"version", "1.2.0"},
{"layout", (asset){#embed "static/layout.mustache.html"}},
{"home", (asset){#embed "static/home.mustache.html"}},
{"get_todos", (asset){#embed "todos/get_todos.sql"}},
{"create_todo", (asset){#embed "todos/create_todo.sql"}}
}
```
### Databases
Each `.databases` entry defines a data store. Migrations are forward-only and index-based: they run in array order, each applied once, with new migrations appended to the end. Seeds are idempotent and safe to re-run. Both are tracked in a `mach_meta` table.
Multi-tenant databases use `{{interpolation}}` in `.connect`. Connections are pooled with LRU eviction.
| Field | Description |
|-------|-------------|
| `.engine` | Database engine constant from a module: `sqlite_db`, `postgres_db`, `mysql_db`, `redis_db`, `duckdb_db` |
| `.name` | Identifier referenced by `.db` in `query()`/`find()` |
| `.connect` | Engine-specific connection string with `{{interpolation}}` |
| `.migrations` | Array of SQL strings or assets, applied once each in order |
| `.seeds` | Array of idempotent statements, safe to re-run on every boot |
```c
.databases = {{
.engine = sqlite_db,
.name = "blog_db",
.connect = "file:{{user_id}}_blog.db?mode=rwc",
.migrations = {
"CREATE TABLE blogs ("
"id INTEGER PRIMARY KEY AUTOINCREMENT,"
"title TEXT NOT NULL,"
"content TEXT NOT NULL"
");",
"CREATE TABLE comments ("
"id INTEGER PRIMARY KEY AUTOINCREMENT,"
"blog_id INTEGER NOT NULL REFERENCES blogs(id),"
"body TEXT NOT NULL"
");"
},
.seeds = {
"INSERT OR IGNORE INTO blogs(id, title, content) VALUES(1, 'Hello', 'First post');"
}
}}
```
A single database can contain multiple tables; declare each as a separate migration in array order.
> **One database = one domain, many tables.** A database maps to a domain (`todos_db`, `blog_db`), not to a single entity. Related tables go as additional migrations on the same database. Reach for a second database when the domain is genuinely separate: audit logs, analytics, third-party cache.
### Resource Pipelines
Each entry in `.resources` defines a named URL endpoint with HTTP verb pipelines. Resources are identified by name: `{{url:name}}`, `redirect()`, and `reroute()` all take a `name[:arg1:arg2...]` identifier with colon-separated positional args. Args fill the `:params` of the URL pattern in order. Path specificity is automatic: exact matches (`/todos/active`) beat parameterized matches (`/todos/:id`) regardless of definition order.
> **`{{url:name}}` with URL params.** Arguments after the name are positional, colon-separated, and can be literals or context keys:
> - ✅ `{{url:todo:5}}` resolves to `/todos/5`
> - ✅ `{{url:todo:id}}` reads `id` from current scope
> - ✅ `{{url:org_todo:acme:5}}` fills multiple `:params` in URL-pattern order
Clients select a verb via the request method, or by passing `http_method` as a query/form parameter. This lets HTML forms (limited to GET/POST) reach any verb, and gives SSE a connection path: `/todos?http_method=sse`.
| Field | Description |
|-------|-------------|
| `.name` *(pos)* | Resource identifier used by `{{url:name}}`, `redirect()`, `reroute()` |
| `.url` *(pos)* | URL pattern with optional `:params` |
| `.steps` *(pos)* | Shared steps run before every verb pipeline (unnamed positional brace block after URL) |
| `.mime` | Default response content type |
| `.get` `.post` `.put` `.patch` `.delete` | Verb pipelines (ordered step arrays) |
| `.sse` | Persistent SSE channel: `{"channel/{{interp}}", steps...}` |
| `.errors` | Resource-scoped terminal error handlers |
| `.repairs` | Resource-scoped resumable repair handlers |
Combined:
```c
{"todo", "/todos/:id", {
validate({"id", .validation = "^\\d+$", .message = "must be a number"})
},
.mime = mime_html,
.get = { find({"get_todo", .set_key = "todo", .db = "todos_db"}),
render("todo") },
.patch = { validate({"title", .validation = validate_not_empty, .message = "required"}),
query({.db = "todos_db",
.query = "update todos set title = {{title}} where id = {{id}};"}),
redirect("todo:{{id}}") },
.delete = { query({.db = "todos_db",
.query = "delete from todos where id = {{id}};"}),
redirect("todos") },
.sse = {"todo/{{id}}", sse(.event = "ready") },
.errors = {{http_not_found, { render("404") }}}
}
```
**MIME types (for `.mime`):** `mime_html`, `mime_txt`, `mime_sse`, `mime_json`, `mime_js`
### Template Helpers
Helpers use `{{helper:args}}` syntax. Args are positional, colon-separated; each can be a literal or a context key.
| Helper | Description |
|--------|-------------|
| `{{raw:field}}` | Emit context value WITHOUT HTML-escaping (`render()` escapes by default) |
| `{{precision:field:N}}` | Format numeric value with N decimal places |
| `{{input:field}}` | Raw, unvalidated request parameter (form repopulation) |
| `{{error:field}}` | Truthy when field has error (use as Mustache section) |
| `{{error_message:field}}` | Human-readable message for field error |
| `{{error_code:field}}` | HTTP status code for field error |
| `{{url:name[:arg1:...]}}` | Resolve resource identifier to URL |
| `{{asset:filename}}` | Resolve file in `public/` to cache-busted URL |
| `{{csrf:token}}` | Random hash, sets httponly/secure/samesite cookie, outputs same value inline |
| `{{csrf:input}}` | Same as `csrf:token` but as hidden `<input>` for forms |
> **CSRF verification is automatic.** MACH checks that the incoming token (from form field or query parameter) matches the value stored in the CSRF cookie and rejects mismatches with a 403. Nothing beyond emitting `{{csrf:token}}` or `{{csrf:input}}` in the rendered response is required.
```c
render(.template =
"<link rel='stylesheet' href='{{asset:styles.css}}'>"
"<article>"
"{{#post}}"
"<h2>{{title}}</h2>"
"<p>Rating: {{precision:score:1}}/5</p>"
"<div>{{raw:body_html}}</div>"
"{{/post}}"
"<form method='post' action='{{url:comments}}'>"
"{{csrf:input}}"
"<input name='body' value='{{input:body}}'>"
"{{#error:body}}<span>{{error_message:body}}</span>{{/error:body}}"
"<button>Comment</button>"
"</form>"
"<a href='{{url:logout}}?csrf={{csrf:token}}'>Log out</a>"
"</article>"
)
```
### Pipeline Steps
Every step accepts `.if_context` and `.unless_context` for conditional execution.
#### validate
Checks request parameters (query string, form body, URL params) against regex patterns. On success, each value is promoted from `input:name` to app scope. On failure, errors land in `error:name` and a `400 Bad Request` triggers the nearest error/repair pipeline. All validations in one call complete before the error fires.
| Field | Description |
|-------|-------------|
| `.param_key` *(pos)* | Parameter name |
| `.validation` | Regex pattern or built-in validator macro |
| `.message` | Human-readable error |
| `.optional` | Skip if parameter absent |
| `.fallback` | Default value if absent |
```c
validate(
{"email", .validation = validate_email, .message = "must be a valid email"},
{"title", .validation = validate_not_empty, .message = "cannot be empty"},
{"page", .fallback = "1",
.validation = "^\\d+$", .message = "must be a number"},
{"filter", .optional = true,
.validation = "^(active|done)$", .message = "must be 'active' or 'done'"}
)
```
**Built-in validators** (define your own with `#define validate_zipcode "^\\d{5}$"`):
- Strings: `validate_not_empty`, `validate_alpha`, `validate_alphanumeric`, `validate_slug`, `validate_no_html`
- Numbers: `validate_integer`, `validate_positive`, `validate_float`, `validate_percentage`
- Identity: `validate_email`, `validate_uuid`, `validate_username`
- Dates & times: `validate_date`, `validate_time`, `validate_datetime`
- Web: `validate_url`, `validate_ipv4`, `validate_hex_color`
- Codes: `validate_zipcode_us`, `validate_phone_e164`, `validate_cron`
- Security: `validate_no_sqli`, `validate_token`, `validate_base64`
- Boolean: `validate_boolean`, `validate_yes_no`, `validate_on_off`
#### find & query
Both run database queries. `.db` selects the database, `.set_key` stores the result in context as a table (even single-row). Templates open the table as a section to reach fields. SQL is either inlined with `.query` or referenced by name as the positional, in which case it is loaded from `.context`. Multiple items in a single step run **concurrently**. Queries use prepared statements; interpolated `{{values}}` are bound, not spliced. For transactions, use `BEGIN`/`COMMIT`/`ROLLBACK` directly.
The only difference: `find()` raises `404 Not Found` when zero rows; `query()` does not.
| Field | Description |
|-------|-------------|
| `.template_key` *(pos)* | SQL asset name in `.context` (mutually exclusive with `.query`) |
| `.query` | Inline SQL with `{{interpolation}}` (mutually exclusive with positional asset name) |
| `.set_key` | Context key for result table |
| `.db` | Database name matching a `.databases` entry |
| `.if_context` / `.unless_context` *(per item)* | Conditionally include/skip individual queries |
> **Positional asset name OR `.query`, not both.**
> - ✅ `query({"get_todos", .set_key = "todos", .db = "todos_db"})`
> - ✅ `query({.set_key = "todos", .db = "todos_db", .query = "select id, title from todos;"})`
> - ❌ Combining the two is rejected
> **Concurrency = multiple items in one step, not multiple steps.** `query({...}, {...})` runs both in parallel. Two back-to-back `query({...})` steps run serially.
```c
query(
{"get_todos", .set_key = "todos", .db = "todos_db"},
{.set_key = "count", .db = "todos_db",
.query = "select count(*) as n from todos where user_id = {{user_id}};"},
{.if_context = "show_urgent", .set_key = "urgent", .db = "todos_db",
.query = "select id, title from todos where user_id = {{user_id}} and priority = 'high';"}
)
```
#### join
Nests records from one context table into each matching record of another (in-memory JOIN). After the step, each outer record gains a new field holding its matched inner records.
This nesting only works if `render()` opens the outer table as a section. A template that iterates both tables as siblings at root treats `join()` as a no-op.
| Field | Description |
|-------|-------------|
| `.target_table_key` | Outer table receiving nested children |
| `.target_field_key` | Field on outer to match against |
| `.nested_table_key` | Inner table to nest |
| `.nested_field_key` | Field on inner pointing at outer |
| `.target_join_field_key` | New field on outer holding matched inner records |
```c
join(
.target_table_key = "blog",
.target_field_key = "id",
.nested_table_key = "comments",
.nested_field_key = "blog_id",
.target_join_field_key = "comments"
)
```
Context shape:
```
after query(): { blog: [{id, title, content}],
comments: [{id, blog_id, body}, ...] }
after join(): { blog: [{id, title, content,
comments: [{id, blog_id, body}, ...]}] }
```
Common failure modes (both produce empty-looking output):
1. Assuming the blog's fields are flat at root because `blog` has one row.
2. Iterating `{{#comments}}` at root instead of from within `{{#blog}}`.
```c
// ❌ Wrong — fields assumed flat at root, comments iterated at root:
render(.template =
"<article>"
"<h1>{{title}}</h1>" // empty
"<div>{{content}}</div>" // empty
"<ul>{{#comments}}<li>{{body}}</li>{{/comments}}</ul>" // empty or unnested
"</article>"
)
// ✅ Right — enter {{#blog}} first; reach comments from within:
render(.template =
"<article>"
"{{#blog}}"
"<h1>{{title}}</h1>"
"<div>{{content}}</div>"
"<ul>{{#comments}}<li>{{body}}</li>{{/comments}}</ul>"
"{{/blog}}"
"</article>"
)
```
#### fetch
Makes an HTTP request and stores the response in context. JSON is parsed into tables and records (with nested tables for nested JSON); plain-text responses are stored as a string.
| Field | Description |
|-------|-------------|
| `.url` *(pos)* | Request URL with `{{interpolation}}` |
| `.set_key` | Context key for the response |
| `.method` | HTTP method (default `http_get`) |
| `.headers` | Array of `{name, value}` pairs |
| `.json` | Context key serialized as JSON request body |
| `.text` | Context key sent as plain-text request body |
```c
fetch("https://api.payments.dev/charge",
.set_key = "receipt",
.method = http_post,
.headers = {
{"Authorization", "Bearer {{api_key}}"},
{"Idempotency-Key", "{{order_id}}"}
},
.json = "order"
)
```
**HTTP methods (for `.method`):** `http_get`, `http_post`, `http_put`, `http_patch`, `http_delete`, `http_sse_method`
#### exec
Calls a C function or block with access to the context via the Imperative API. Execution is dispatched to the shared thread pool, which releases the reactor; the pipeline resumes on the original reactor when the call returns. Suitable for blocking I/O and CPU-heavy work. To trigger an error/repair pipeline from inside, call `error_set()`.
| Field | Description |
|-------|-------------|
| Block *(pos)* | Inline `^(){ ... }` block |
| `.call` | Reference to a named C function |
```c
exec(^(){
auto t = get("challengers");
record_set(table_get(t, 0), "opponent_id",
record_get(table_get(t, 1), "id"));
})
exec(.call = assign_opponents)
```
**Imperative API** (available from `exec` blocks and functions):
- Context: `get(name)`, `set(name, value)`, `has(name)`, `format(fmt)`
- Memory: `allocate(bytes)`, `defer_free(ptr)`
- Errors: `error_set(name, err)`, `error_get(name)`, `error_has(name)`
- Tables: `table_new()`, `table_count(t)`, `table_get(t, i)`, `table_add(t, r)`, `table_remove(t, r)`, `table_remove_at(t, i)`
- Records: `record_new()`, `record_set(r, name, value)`, `record_get(r, name)`, `record_remove(r, name)`
#### emit
Triggers an internal pub/sub event. Subscribers in other modules react in their `.events` pipelines.
```c
emit("todo_created")
```
#### task
Adds a named job to the task database and continues immediately. Fire-and-forget. Task reactors pick up queued jobs.
```c
task("recount_todos")
```
#### sse
Pushes a Server-Sent Event. With `.channel`: broadcast to all clients on that channel. Without: returned to the requesting client.
| Field | Description |
|-------|-------------|
| `.channel` *(pos)* | Broadcast channel with `{{interpolation}}` |
| `.event` | SSE `event:` line value |
| `.data` | Array of strings, one per `data:` line |
| `.comment` | SSE `:` comment line |
```c
sse(
.channel = "todos/{{user_id}}",
.event = "todo_updated",
.data = {"id: {{todo_id}}", "title: {{title}}"},
.comment = "broadcast at {{timestamp}}"
)
```
#### ds_sse
Datastar-formatted SSE for DOM updates and reactive client state. Provided by the `datastar` module. With channel: broadcast. Without: requesting client only.
| Field | Description |
|-------|-------------|
| `.channel` *(pos)* | Broadcast channel with `{{interpolation}}` |
| `.target` | DOM element id for the update |
| `.mode` | Fragment insertion mode |
| `.elements` | `render_config` for the DOM fragment (positional asset name; supports `.template`, `.engine`) |
| `.signals` | JSON string updating Datastar reactive client state without touching DOM |
| `.js` | JS snippet evaluated on client |
```c
ds_sse("todos/{{user_id}}",
.target = "todo-list",
.mode = mode_prepend,
.elements = {"todo_row"},
.signals = "{\"count\": {{count}}}",
.js = "window.scrollTo(0, 0)"
)
```
**Modes:** `mode_outer`, `mode_inner`, `mode_replace`, `mode_prepend`, `mode_append`, `mode_before`, `mode_after`, `mode_remove`
#### render
Outputs a Mustache template using the current context. Templates are referenced by name from `.context` or inlined. Sections only, no dot paths.
| Field | Description |
|-------|-------------|
| `.template_key` *(pos)* | Asset name in `.context` |
| `.template` | Inline Mustache template string |
| `.status` | HTTP response status (default `http_ok`) |
| `.mime` | Override response content type |
| `.engine` | `mustache` (default) or `mdm` (Markdown-with-Mustache); accepts bare identifier or string |
| `.json_table_key` | Context table to serialize as JSON response (auto-sets `application/json`) |
```c
render("todos")
render(.template = "<h1>Hello {{name}}</h1>")
render("not_found", .status = http_not_found)
render(.engine = mdm, .template = "# Hello {{name}}\n\nYou have **{{count}}** todos.")
render(.json_table_key = "todos")
```
> **Mustache tags live inside C string literals.** Inline templates are concatenated by adjacent-string-literal rules. Every Mustache tag, including section open/close tags on their own lines, must be inside quotes.
> - ✅ Multi-line with section tags on their own quoted lines (the canonical format):
> ```c
> "<article>"
> "{{#blog}}"
> "<h1>{{title}}</h1>"
> "<ul>{{#comments}}<li>{{body}}</li>{{/comments}}</ul>"
> "{{/blog}}"
> "</article>"
> ```
> - ❌ Section tags on their own lines without quotes — compile error:
> ```c
> "<article>"
> {{#blog}} // NOT in quotes
> "<h1>{{title}}</h1>"
> {{/blog}}
> "</article>"
> ```
**HTTP statuses (for `.status`):** `http_ok` (200), `http_created` (201), `http_redirect` (302), `http_bad_request` (400), `http_not_authorized` (401), `http_not_found` (404), `http_error` (500)
**MIME types (for `.mime`):** `mime_html`, `mime_txt`, `mime_sse`, `mime_json`, `mime_js`
#### headers & cookies
Set HTTP response headers and cookies declaratively. Both accept an array of name/value pairs; values support `{{interpolation}}`.
```c
headers({{"X-Request-Id", "{{request_id}}"}, {"Cache-Control", "no-store"}})
cookies({{"session", "{{session_id}}"}})
```
#### redirect & reroute
`redirect()` returns a 302 to the client (browser navigates). `reroute()` re-enters the router server-side, executing another resource's pipeline within the same request. Both take a resource identifier in the same `name[:arg1:arg2...]` format as `{{url:name}}`. Args can be literals or context keys, and support `{{interpolation}}`. **Context persists across reroute** (input/error scopes preserved).
```c
redirect("todos") // 302 to /todos
redirect("todo:5") // 302 to /todos/5
redirect("todo:{{id}}") // 302 to /todos/{{id}} from context
redirect("org_todo:acme:5") // 302 to /orgs/acme/todos/5
reroute("todo:{{id}}") // run that pipeline in-process
```
#### nest
Groups multiple steps into a single composite step. Apply one `.if_context`/`.unless_context` to a group instead of repeating per step.
```c
nest({query({...}), emit("urgent_todo"), render("urgent")},
.if_context = "is_urgent")
```
### Conditionals
Every step accepts `.if_context` and `.unless_context`, which name a context variable. Works for any context value: validated inputs, query results, framework flags such as `is_htmx`, or flags set from `exec()`.
```c
render("fragment", .if_context = "is_htmx")
render("full_page", .unless_context = "is_htmx")
```
For multi-state branching, set context flags from `exec()`, then key downstream steps off them:
```c
exec(.call = classify_todo),
render("urgent_confirmation", .if_context = "is_urgent"),
render("standard_confirmation", .unless_context = "is_urgent")
```
### Error and Repair Pipelines
When a pipeline step fails, execution halts and MACH searches for a handler bottom-up: resource → module → root. Errors are **terminal**: the matching pipeline sends a response and ends the request. Repairs are **resumable**: they fix the context and resume the original pipeline at the step after the failure. If no matching repair is found, resolution falls through to errors.
The `error` scope is shared across `validate()` failures and `error_set()` calls: `{{error:name}}`, `{{error_code:name}}`, `{{error_message:name}}`. Raw input remains in `input:name` for re-rendering forms.
```c
.errors = {
{http_not_found, { render("404") }},
{http_bad_request, { render("form") }},
{http_error, { render("500") }}
},
.repairs = {
{http_not_authorized, { exec(.call = refresh_session_token) }}
}
```
**Built-in error codes (for the `.error_code` positional):** `http_ok` (200), `http_created` (201), `http_redirect` (302), `http_bad_request` (400), `http_not_authorized` (401), `http_not_found` (404), `http_error` (500). Any integer works; the `http_*` constants are convenience names. Define your own for domain errors, e.g. `#define err_quota_exceeded 723`.
### Event Pipelines
Internal pub/sub for cross-module communication. The publisher doesn't know who listens; the subscriber doesn't know who emits. Adding a subscriber is a new module with an `.events` entry, no changes to the publisher.
Events are durable by default. When `.publishes` is defined anywhere, MACH creates a `mach_events` database to track delivery. Process crash → undelivered events replay on next boot.
```c
// publisher
.publishes = {
{"todo_created", .with = {"user_id", "title"}}
},
.resources = {
{"todos", "/todos",
.post = {
validate({"title", .validation = validate_not_empty}),
query({"insert_todo", .db = "todos_db"}),
emit("todo_created"),
redirect("todos")
}
}
}
// subscriber (separate module)
.events = {
{"todo_created", {
query({.db = "activity_db",
.query = "insert into activities(kind, user_id, ref) "
"values('created', {{user_id}}, {{title}});"})
}}
}
```
### Task Pipelines
Tasks are named pipelines that run asynchronously on task reactors. Fire-and-forget. Defined at module or root level. Triggered on demand with `task("name")` or on a schedule via `.cron`. Tasks can enqueue more tasks via `task()`.
Tasks are durable by default. When `.tasks` is defined, MACH creates a `mach_tasks` database and checkpoints context after each step. Crash mid-task → resumes at the exact step where it left off.
| Field | Description |
|-------|-------------|
| `.name` *(pos)* | Task identifier called via `task("name")` |
| Steps *(pos)* | Pipeline body (second positional brace block, before designated fields) |
| `.accepts` | Context keys to pull from caller into the task |
| `.cron` | Standard cron schedule for recurring tasks (no caller required) |
```c
.tasks = {
// on-demand: enqueued via task("recount_todos")
{"recount_todos", {
query({.db = "todos_db",
.query = "update users set todo_count = "
"(select count(*) from todos where user_id = users.id) "
"where id = {{user_id}};"})
}, .accepts = {"user_id"}},
// recurring: runs on schedule, no caller
{"daily_digest", {
query({.db = "todos_db",
.query = "insert into digest_reports(generated_at) values(now());"}),
emit("digest_ready")
}, .cron = "0 8 * * *"}
}
```
### Modules & Composition
Every MACH app and module returns a `config` struct. The root `main.c` must define a function named `mach()`; modules define their own functions with any name and register them in `.modules` by bare function reference. A module owns its own resources, databases, migrations, templates, and event contracts.
When the root and a module both define something with the same name (a context variable, a database, an error handler), the **root wins**. Modules don't call each other directly; they communicate through pub/sub events.
| Field | Description |
|-------|-------------|
| `.name` | Module identifier |
| `.modules` | Other modules to compose into this one (root or nested) |
Bring the module into scope by `#include`ing its `.c` file from `main.c`, then register it with `.modules`.
```c
// main.c
#include <mach.h>
#include "blogs/blogs.c"
config mach(){ return (config){ .modules = {blogs, sqlite} }; }
```
A module returns a `config` with the same shape as the root app (`.resources`, `.databases`, `.events`, etc.), plus a `.name` for identity. Resource fields like `.url`, `.mime`, `.get` are not top-level config fields; they belong inside entries of `.resources`.
```c
#include <mach.h>
#include <sqlite.h>
config blogs(){
return (config){
.name = "blogs",
.resources = {
{"blog", "/blogs/:id",
.get = { /* validate → query → join → render */ }
}
},
.databases = {{
.engine = sqlite_db,
.name = "blog_db",
.connect = "file:blogs.db?mode=rwc",
.migrations = {
"CREATE TABLE blogs ("
"id INTEGER PRIMARY KEY AUTOINCREMENT,"
"title TEXT NOT NULL,"
"content TEXT NOT NULL"
");",
"CREATE TABLE comments ("
"id INTEGER PRIMARY KEY AUTOINCREMENT,"
"blog_id INTEGER NOT NULL REFERENCES blogs(id),"
"body TEXT NOT NULL"
");"
}
}}
};
}
```
Project layout:
```
todos/ # todos module
├── todos.c # config todos() { ... }
├── todos.mustache.html
├── create_todos_table.sql
└── get_todos.sql
activity/ # activity module
└── activity.c
static/ # root-level templates (NOT a module)
├── layout.mustache.html
└── home.mustache.html
public/ # static files served directly
└── favicon.png
main.c # registers modules
```
**Bundled modules (add the initializer to `.modules` to use):** `sqlite`, `postgres`, `mysql`, `redis`, `duckdb`, `htmx`, `datastar`, `tailwind`, `session_auth`
**Module-provided steps.** Modules can ship step functions that plug into pipelines alongside built-in steps. The `session_auth` module provides:
- `session()` — attaches the current session to context (sets `user_id`, etc.); no-op when unauthenticated
- `logged_in()` — guard that raises `http_not_authorized` when there's no active session
- `login()`, `logout()`, `signup()` — use inside POST pipelines to perform the auth action
Common pattern: drop into a resource's shared `.steps` slot as middleware:
```c
{"dashboard", "/dashboard", {session(), logged_in()},
.get = { render("dashboard") }
}
```
### Static Files
Files placed in `public/` at the project root are served directly. Use it for images, fonts, pre-built CSS/JS. Reference them with `{{asset:filename}}`, which resolves to a URL with a content-based checksum and immutable cache headers.
```html
<link rel="icon" href="{{asset:favicon.png}}">
<link rel="stylesheet" href="{{asset:styles.css}}">
<script src="{{asset:app.js}}"></script>
```
### External Dependencies
MACH expects a containerized dev environment. Standard C23 against MACH APIs; no local toolchain required.
**`/vendor` directory**: drop headers and libraries (`.so`, `.a`); the auto-compiler discovers, includes, and links them.
```
/vendor/
├── libsodium.h
└── libsodium.so
```
**Custom `Dockerfile`**: inherit from the MACH base image and `apt-get install` system deps; reference from `compose.yml`.
```dockerfile
FROM mach:latest
RUN apt-get update && apt-get install -y libsodium-dev
```
**`allocate(bytes)`**: buffer from the pipeline arena, reclaimed on request completion.
```c
char *buf = allocate(256);
```
**`defer_free(ptr)`**: schedules cleanup for pointers from external libraries (e.g. via `malloc`); runs when the arena is released.
```c
char *out = third_party_alloc(256);
defer_free(out);
```
Reference in New Issue Copy Permalink