Crate seam_core 

The Seam validation engine. Every binding is a translation layer over this crate and contains no validation logic of its own. If a binding starts growing rules, that is a leak here, to be fixed here.

use seam_core::{parser::parse, validate::validate, value::Value, Limits};
use std::collections::BTreeMap;

let schema = parse("schema Signup { when: DateTime }")?;

let mut payload = BTreeMap::new();
payload.insert("when".to_string(), Value::String("2026-08-29T14:30:00".into()));

let err = validate(&schema, "Signup", &Value::Object(payload), Limits::DEFAULT)
    .unwrap_err();
assert_eq!(err.issues[0].code.as_str(), "missing_timezone");

Re-exports

pub use error::Code;

pub use error::Issue;

pub use error::Path;

pub use error::Segment;

pub use error::ValidationError;

pub use format::Format;

pub use limits::Limits;

pub use parser::parse;

pub use schema::Field;

pub use schema::IntType;

pub use schema::IntWidth;

pub use schema::ObjectType;

pub use schema::Presence;

pub use schema::Rule;

pub use schema::Schema;

pub use schema::Type;

pub use validate::validate;

pub use value::Int;

pub use value::Slot;

pub use value::Value;

Modules

datetime

Written here rather than delegated to a date crate because the two rules that matter are policy, not parsing: a Date is never widened into an instant, and a DateTime without an offset is an error rather than a guess about local time. Typed conversion happens in the bindings.

error

path and code are public API in every binding. code is stable and changes only on a major version; message is for humans, never parse it.

format

Named string formats, checked by hand.

input

What the validator needs from a payload, and nothing more.

json

JSON read in place.

limits

Bounds on hostile input, enforced in the core so every binding inherits them instead of each deriving its own defaults.

parser

The .seam front end.

schema

validate

One walk over the payload, reading it in place.

value

Constants

VERSION