Language overview

A .prim file is a sequence of top-level items, separated by newlines. There are six kinds of item:

Item	Spelling	Notes
Constant	`<type> <NAME> = <value>`	One per line
Enum	`enum Name { Variant, … }`	Optionally integer-backed
Type alias	`type Name = <type>`	Reusable type expression
`use` import	`use ns::Name` / `use ns::{A, B}`	Cross-namespace ergonomic
`namespace` override	`namespace foo::bar`	Escape hatch (see below)
Comments	`//`, `///`, `//!`	Line, doc, file-doc

A real-world snippet:

/// Maximum upload size, enforced by the gateway.
u64 MAX_UPLOAD = 100MiB

/// Severity of a log line, integer-backed for fast filtering.
enum LogLevel: u8 {
    Debug = 0,
    Info  = 1,
    Warn  = 2,
    Error = 3,
}

type Port = u32

Port HTTP_PORT  = 8080
Port HTTPS_PORT = 8443

Identifiers and naming

primate enforces case conventions. The formatter doesn’t fix violations — the parser surfaces a naming-convention diagnostic.

Item	Convention	Example
Constants	`SCREAMING_SNAKE_CASE`	`MAX_UPLOAD`
Enums	`PascalCase`	`LogLevel`
Enum variants	`PascalCase`	`Warn`
Type aliases	`PascalCase`	`Port`
Namespaces	`lower_snake_case`	`core::time`

Namespaces

Each .prim file belongs to exactly one namespace. By default the namespace comes from the file’s path relative to the project’s input directory:

constants/                ← input
├── limits.prim           → namespace `limits`
├── time.prim             → namespace `time`
└── net/
    └── ports.prim        → namespace `net::ports`

This is the recommended way to organize. Don’t write namespace foo at the top of every file — let the directory layout do it. The explicit form is an escape hatch when you want a file’s contents to live somewhere other than the path implies.

// constants/legacy/old_metrics.prim
namespace metrics::v1
// — overrides the path-derived `legacy::old_metrics`.

Files sharing a namespace share a flat scope: enums and aliases declared in one are visible in all, by bare name. Cross-namespace references go through fully qualified paths or use statements.

Resolution rules

When you write a bare type name like LogLevel, primate looks for it in:

The current file.
Sibling files in the same namespace.
Names brought into scope by use statements.
(Otherwise: unknown-type error. Use a fully qualified path.)

A few syntactic rules

No expressions in values. Every constant is a literal of its declared type. No 60 * 60, no BASE * 2.
No statement-terminating semicolons. Newlines terminate.
Inside (), [], {}, <> newlines are insignificant — handy for wrapping long type expressions or value literals.
One comment style per role. // line, /// doc, //! file doc. No block comments.

Some features you might expect (expressions, newtype nominal types, string interpolation) aren’t in the language. See the roadmap for what’s under consideration.

Where to read next

Declarations — const, enum, type, namespace.
Types — primitives, container constructors, fixed arrays.
Values — literals, including the magic trailing comma.
use statements.
Attributes — @inline and the plugin extension story.
Formatting — what primate fmt does.