prosaic-core

General-purpose natural language generation from structured data.

prosaic-core turns structured events into deterministic prose. It tracks discourse state across renders, so consecutive sentences can use pronouns, connectives, varied list styles, salience-aware template variants, and document-level aggregation without depending on an LLM.

Install

[dependencies]
prosaic-core = "1.0.1"
prosaic-grammar-en = "1.0.1"

Add prosaic-derive for compile-time context and template checks, and add a vocabulary crate such as prosaic-vocab-code when you want built-in templates.

Quick Start

use prosaic_core::{Context, Engine, Session, Strictness, Value, Variation};
use prosaic_grammar_en::English;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut engine = Engine::new(English::new())
        .strictness(Strictness::Strict)
        .variation(Variation::Fixed);

    engine.register_template(
        "entity.renamed",
        "{old_name|refer} was renamed to {new_name}",
    )?;

    let mut ctx = Context::new();
    ctx.insert("entity_type", Value::String("class".into()));
    ctx.insert("old_name", Value::String("Foo".into()));
    ctx.insert("new_name", Value::String("Foobar".into()));

    let mut session = Session::new();
    let sentence = engine.render(&mut session, "entity.renamed", &ctx)?;
    assert_eq!(sentence, "The class Foo was renamed to Foobar.");
    Ok(())
}

Highlights

Template syntax with slots, pipes, conditionals, partials, and variant tiers.
Discourse-aware references through {name|refer} and {name|possessive}.
Salience-aware variant selection and deterministic variation strategies.
Document planning and batch rendering for multi-event narratives.
English, Spanish, and German support through sibling grammar crates.
Optional serde, parallel rendering, polish, relative-time, and REG features.
no_std + alloc support with default-features = false.

Cargo Features

std (default): standard-library error support and system-time fallbacks.
time (default): {ts|relative} and {ts|since_last} pipes.
polish (default): smart quotes and sentence-length splitting.
reg (default): referring-expression generation.
serde: serialization for core public data types.
parallel: rayon-backed document paragraph rendering.

License