tame/tamer/src/global.rs

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// Global constants across the entirety of TAMER
//
// Copyright (C) 2014-2023 Ryan Specialty, LLC.
2020-03-06 11:05:18 -05:00
//
// This file is part of TAME.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//! System-wide static configuration.
//!
//! This module provides a system-wide configuration.
//! Subsystems should reference these values rather than defining their own
//! and risk incompatibilities or maintenance issues as requirements
//! change.
//!
//! This package contains static assertions to ensure that certain sizes
//! will play well with one-another and provide a clear direction if
//! something goes wrong
//! (beyond a slew of other type errors).
//!
//! By convention,
//! import this entire module rather than individual members and reference
//! them as `global::foo` to emphasize their nature and risk.
use std::{mem::size_of, num};
/// The initial capacity for global interners.
pub const INIT_GLOBAL_INTERNER_CAPACITY: usize = 1024;
/// A size capable of representing every interned string in a program.
pub type ProgSymSize = u32;
/// A non-zero equivalent of [`ProgSymSize`];
pub type NonZeroProgSymSize = num::NonZeroU32;
/// Size large enough to accommodate the number of bytes in a source file.
pub type SourceFileSize = u32;
/// Length of tokens derived from source files.
///
/// This size should be kept small,
/// since its principle use is as an alternative to a byte offset
/// ([`SourceFileSize`]) for struct packing.
/// It should, however, be large enough to handle comment and
/// documentation tokens.
/// Tokens that are too large can potentially be split into multiple
/// tokens.
pub type FrontendTokenLength = u16;
const_assert!(size_of::<FrontendTokenLength>() <= size_of::<SourceFileSize>());
/// A size capable of representing the union of every identifier of every
/// package used by an entire program.
///
/// This must be ≥ [`ProgSymSize`].
pub type ProgIdentSize = u32;
const_assert!(size_of::<ProgIdentSize>() >= size_of::<ProgSymSize>());
/// A size capable of representing the union of every identifier and every
/// expression of every package used by an entire program.
///
/// Note that,
/// since TAME is a metalanguage and can easily expand into a great
/// deal of code,
/// this must accommodate far more than the user's expectations
/// working within the provided level of abstraction.
///
/// This must be ≥ [`ProgSymSize`].
pub type ProgIdentExprSize = u32;
const_assert!(size_of::<ProgIdentExprSize>() >= size_of::<ProgSymSize>());