tame/tamer/src/asg/air/tpl.rs

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// ASG IR template parsing
//
// Copyright (C) 2014-2023 Ryan Specialty, LLC.
//
// 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/>.
//! AIR template parser.
//!
//! See the [parent module](super) for more information.
use super::{
super::{
graph::object::{Pkg, Tpl},
Asg, AsgError, ObjectIndex,
},
Air, AirExprAggregate,
};
use crate::{
fmt::{DisplayWrapper, TtQuote},
parse::prelude::*,
};
/// Template parser and token aggregator.
///
/// A template consists of
///
/// - Metadata about the template,
/// including its parameters; and
/// - A collection of [`Air`] tokens representing the body of the
/// template that will be expanded into the application site when the
/// template is applied.
///
/// This contains an embedded [`AirExprAggregate`] parser for handling
/// expressions just the same as [`super::AirAggregate`] does with
/// packages.
#[derive(Debug, PartialEq, Eq)]
pub enum AirTplAggregate {
/// Ready for a template,
/// defined as part of the given package.
///
/// This state also include the template header;
/// unlike NIR,
/// AIR has no restrictions on when template header tokens are
/// provided,
/// which simplifies AIR generation.
///
/// The expression parser [`AirExprAggregate`] is initialized at this
/// state to avoid re-allocating its stack for adjacent templates.
/// This will not save any allocations if,
/// after reaching a dead state,
/// the caller
/// (or parent parser)
/// chooses to deallocate us.
Ready(ObjectIndex<Pkg>, AirExprAggregate),
/// Aggregating tokens into a template.
BuildingTpl(
ObjectIndex<Pkg>,
ObjectIndex<Tpl>,
AirExprAggregate,
Option<SPair>,
),
}
impl Display for AirTplAggregate {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
match self {
Self::Ready(_, _) => write!(f, "ready for template definition"),
Self::BuildingTpl(_, expr, _, None) => {
write!(f, "building anonymous template with {expr}")
}
Self::BuildingTpl(_, expr, _, Some(name)) => {
write!(
f,
"building named template {} with {expr}",
TtQuote::wrap(name)
)
}
}
}
}
impl ParseState for AirTplAggregate {
type Token = Air;
type Object = ();
type Error = AsgError;
type Context = Asg;
fn parse_token(
self,
tok: Self::Token,
asg: &mut Self::Context,
) -> TransitionResult<Self::Super> {
use super::ir::{AirBind::*, AirSubsets::*, AirTodo::*, AirTpl::*};
use AirTplAggregate::*;
match (self, tok.into()) {
(st, AirTodo(Todo(_))) => Transition(st).incomplete(),
(Ready(oi_pkg, expr), AirTpl(TplOpen(span))) => {
let oi_tpl = asg.create(Tpl::new(span));
Transition(BuildingTpl(oi_pkg, oi_tpl, expr, None)).incomplete()
}
(
BuildingTpl(oi_pkg, oi_tpl, expr, _),
AirBind(BindIdent(name)),
) => asg
.lookup_or_missing(name)
.bind_definition(asg, name, oi_tpl)
.map(|oi_ident| oi_pkg.defines(asg, oi_ident))
.map(|_| ())
.transition(BuildingTpl(oi_pkg, oi_tpl, expr, Some(name))),
(BuildingTpl(oi_pkg, oi_tpl, expr, _), AirTpl(TplClose(span))) => {
oi_tpl.close(asg, span);
Transition(Ready(oi_pkg, expr)).incomplete()
}
(BuildingTpl(..), AirPkg(_)) => {
todo!("template cannot define packages")
}
(BuildingTpl(..), tok) => todo!("BuildingTpl body: {tok:?}"),
(st @ Ready(..), AirTpl(TplClose(span))) => {
Transition(st).err(AsgError::UnbalancedTpl(span))
}
(
st @ Ready(..),
tok @ (AirPkg(..) | AirExpr(..) | AirBind(..) | AirIdent(..)),
) => Transition(st).dead(tok.into()),
}
}
fn is_accepting(&self, _: &Self::Context) -> bool {
matches!(self, Self::Ready(..))
}
}
impl AirTplAggregate {
pub(super) fn new_in_pkg(oi_pkg: ObjectIndex<Pkg>) -> Self {
Self::Ready(oi_pkg, AirExprAggregate::new_in_pkg(oi_pkg))
}
}
#[cfg(test)]
mod test;