387 lines
12 KiB
Rust
387 lines
12 KiB
Rust
// ASG IR template parsing
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//
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// Copyright (C) 2014-2023 Ryan Specialty, LLC.
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//
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// This file is part of TAME.
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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//! AIR template parser.
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//!
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//! See the [parent module](super) for more information.
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use super::{
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super::{graph::object::Tpl, Asg, AsgError, ObjectIndex},
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expr::AirExprAggregateStoreDangling,
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ir::AirTemplatable,
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AirAggregateCtx, AirExprAggregate,
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};
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use crate::{
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asg::graph::object::{Meta, ObjectIndexRelTo},
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diagnose::Annotate,
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diagnostic_todo,
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fmt::{DisplayWrapper, TtQuote},
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parse::prelude::*,
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span::Span,
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};
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/// Template parser and token aggregator.
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///
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/// A template consists of
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///
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/// - Metadata about the template,
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/// including its parameters; and
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/// - A collection of [`AirTemplatable`] tokens representing the body of
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/// the template that will be expanded into the application site when
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/// the template is applied.
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///
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/// This contains an embedded [`AirExprAggregate`] parser for handling
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/// expressions just the same as [`super::AirAggregate`] does with
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/// packages.
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#[derive(Debug, PartialEq)]
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pub enum AirTplAggregate {
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/// Ready for a template,
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/// defined as part of the given package.
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///
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/// This state also includes the template header;
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/// unlike NIR,
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/// AIR has no restrictions on when template header tokens are
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/// provided,
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/// which simplifies AIR generation.
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Ready,
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/// Toplevel template context.
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///
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/// Conceptually,
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/// tokens that are received in this state are interpreted as directly
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/// applying to the template itself,
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/// or creating an object directly owned by the template.
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Toplevel(TplState),
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/// Defining a template metavariable.
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TplMeta(TplState, ObjectIndex<Meta>),
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/// Aggregating tokens into a template.
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TplExpr(TplState, AirExprAggregateStoreDangling),
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}
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impl Display for AirTplAggregate {
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fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
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match self {
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Self::Ready => write!(f, "ready for template definition"),
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Self::Toplevel(tpl) => write!(f, "building {tpl} at toplevel"),
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Self::TplExpr(tpl, expr) => {
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write!(f, "building {tpl} with {expr}")
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}
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Self::TplMeta(tpl, _) => {
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write!(f, "building {tpl} metavariable")
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}
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}
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}
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}
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/// The current reachability status of the template.
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#[derive(Debug, PartialEq, Eq, Clone, Copy)]
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pub enum TplState {
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/// Template is dangling and cannot be referenced by anything else.
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Dangling(ObjectIndex<Tpl>),
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/// Template is anonymous and is not reachable by an identifier,
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/// but is reachable in the current context.
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AnonymousReachable(ObjectIndex<Tpl>),
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/// Template is reachable via an identifier.
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///
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/// This uses an [`SPair`] as evidence for that assertion rather than an
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/// [`ObjectIndex`] so that it provides useful output via [`Display`]
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/// in parser traces.
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Identified(ObjectIndex<Tpl>, SPair),
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}
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impl TplState {
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fn oi(&self) -> ObjectIndex<Tpl> {
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match self {
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TplState::Dangling(oi)
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| TplState::AnonymousReachable(oi)
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| TplState::Identified(oi, _) => *oi,
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}
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}
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fn identify(self, id: SPair) -> Self {
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Self::Identified(self.oi(), id)
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}
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fn anonymous_reachable(self) -> Self {
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Self::AnonymousReachable(self.oi())
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}
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/// Attempt to complete a template definition.
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///
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/// If `self` is [`Self::Dangling`],
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/// then an [`AsgError::DanglingTpl`] will be returned.
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///
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/// This updates the span of the template to encompass the entire
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/// definition,
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/// even if an error occurs.
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fn close(self, asg: &mut Asg, close_span: Span) -> Result<(), AsgError> {
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let oi = self.oi().close(asg, close_span);
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match self {
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Self::Dangling(_) => {
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Err(AsgError::DanglingTpl(oi.resolve(asg).span()))
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}
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Self::AnonymousReachable(..) | Self::Identified(..) => Ok(()),
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}
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}
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}
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impl Display for TplState {
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fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
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match self {
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TplState::Dangling(_) => write!(f, "anonymous dangling template"),
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TplState::AnonymousReachable(_) => {
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write!(f, "anonymous reachable template")
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}
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TplState::Identified(_, id) => {
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write!(f, "identified template {}", TtQuote::wrap(id))
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}
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}
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}
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}
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impl ParseState for AirTplAggregate {
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type Token = AirTemplatable;
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type Object = ();
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type Error = AsgError;
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type Context = AirAggregateCtx;
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fn parse_token(
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self,
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tok: Self::Token,
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ctx: &mut Self::Context,
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) -> TransitionResult<Self::Super> {
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use super::ir::{AirBind::*, AirTpl::*};
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use AirTemplatable::*;
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use AirTplAggregate::*;
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match (self, tok) {
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(Ready, AirTpl(TplStart(span))) => {
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let oi_tpl = ctx.asg_mut().create(Tpl::new(span));
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Transition(Toplevel(TplState::Dangling(oi_tpl))).incomplete()
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}
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(Toplevel(..), AirTpl(TplStart(span))) => diagnostic_todo!(
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vec![span.note("for this template")],
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"nested tpl open"
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),
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(Toplevel(tpl), AirBind(BindIdent(id))) => {
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let oi_root = ctx.rooting_oi().expect("TODO");
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let asg = ctx.asg_mut();
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asg.lookup_global_or_missing(id)
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.bind_definition(asg, id, tpl.oi())
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.map(|oi_ident| oi_root.defines(asg, oi_ident))
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.map(|_| ())
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.transition(Toplevel(tpl.identify(id)))
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}
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(Toplevel(tpl), AirBind(RefIdent(id))) => {
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tpl.oi().apply_named_tpl(ctx.asg_mut(), id);
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Transition(Toplevel(tpl)).incomplete()
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}
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(Toplevel(tpl), AirTpl(TplMetaStart(span))) => {
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let oi_meta = ctx.asg_mut().create(Meta::new_required(span));
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Transition(TplMeta(tpl, oi_meta)).incomplete()
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}
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(TplMeta(tpl, oi_meta), AirTpl(TplMetaEnd(cspan))) => {
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oi_meta.close(ctx.asg_mut(), cspan);
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Transition(Toplevel(tpl)).incomplete()
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}
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(TplMeta(tpl, oi_meta), AirTpl(TplLexeme(lexeme))) => Transition(
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TplMeta(tpl, oi_meta.assign_lexeme(ctx.asg_mut(), lexeme)),
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)
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.incomplete(),
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(TplMeta(tpl, oi_meta), AirBind(BindIdent(name))) => {
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oi_meta.identify_as_tpl_param(ctx.asg_mut(), tpl.oi(), name);
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Transition(TplMeta(tpl, oi_meta)).incomplete()
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}
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(TplMeta(..), tok @ AirBind(RefIdent(..))) => {
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diagnostic_todo!(
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vec![tok.note("this token")],
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"AirBind in metavar context (param-value)"
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)
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}
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(TplMeta(..), tok @ AirExpr(..)) => {
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diagnostic_todo!(
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vec![tok.note("this token")],
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"AirExpr in metavar context (e.g. @values@)"
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)
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}
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(
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TplMeta(..),
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tok @ AirTpl(
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TplStart(..) | TplMetaStart(..) | TplEnd(..)
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| TplEndRef(..),
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),
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) => {
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diagnostic_todo!(vec![tok.note("this token")], "AirTpl variant")
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}
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(Toplevel(..), tok @ AirTpl(TplMetaEnd(..))) => {
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diagnostic_todo!(
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vec![tok.note("this token")],
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"unbalanced meta"
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)
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}
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(Toplevel(..), tok @ AirTpl(TplLexeme(..))) => {
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diagnostic_todo!(
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vec![tok.note("this token")],
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"err: TplLexeme outside of metavar"
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)
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}
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(Toplevel(tpl), AirTpl(TplEnd(span))) => {
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tpl.close(ctx.asg_mut(), span).transition(Ready)
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}
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(TplExpr(tpl, expr), AirTpl(TplEnd(span))) => {
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// TODO: duplicated with AirAggregate
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if expr.is_accepting(ctx) {
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ctx.pop();
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tpl.close(ctx.asg_mut(), span).transition(Ready)
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} else {
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Transition(TplExpr(tpl, expr))
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.err(AsgError::InvalidTplEndContext(span))
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}
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}
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(Toplevel(tpl), AirTpl(TplEndRef(span))) => {
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let oi_target = ctx.expansion_oi().expect("TODO");
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tpl.oi().expand_into(ctx.asg_mut(), oi_target);
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Transition(Toplevel(tpl.anonymous_reachable()))
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.incomplete()
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.with_lookahead(AirTpl(TplEnd(span)))
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}
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(TplExpr(tpl, expr_done), AirTpl(TplEndRef(span))) => {
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let oi_target = ctx.expansion_oi().expect("TODO");
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tpl.oi().expand_into(ctx.asg_mut(), oi_target);
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// TODO: We have to make sure the expression ended first!
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Transition(TplExpr(tpl.anonymous_reachable(), expr_done))
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.incomplete()
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.with_lookahead(AirTpl(TplEnd(span)))
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}
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(Toplevel(tpl), tok @ AirExpr(_)) => {
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ctx.push(Toplevel(tpl));
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Transition(TplExpr(tpl, AirExprAggregate::new()))
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.incomplete()
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.with_lookahead(tok)
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}
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(TplExpr(tpl, expr), AirExpr(etok)) => {
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Self::delegate_expr(ctx, tpl, expr, etok)
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}
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(TplExpr(tpl, expr), AirBind(etok)) => {
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Self::delegate_expr(ctx, tpl, expr, etok)
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}
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(TplExpr(..), AirTpl(TplStart(span))) => {
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diagnostic_todo!(
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vec![span.note("for this token")],
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"nested template (template-generated template)"
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)
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}
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(
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Ready | TplExpr(..),
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tok @ AirTpl(TplMetaStart(..) | TplLexeme(..) | TplMetaEnd(..)),
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) => {
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diagnostic_todo!(
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vec![tok.note("for this token")],
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"metasyntactic token in non-tpl-toplevel context: {tok:?}"
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)
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}
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(st @ Ready, AirTpl(TplEnd(span) | TplEndRef(span))) => {
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Transition(st).err(AsgError::UnbalancedTpl(span))
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}
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(st @ Ready, tok @ (AirExpr(..) | AirBind(..))) => {
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Transition(st).dead(tok)
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}
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}
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}
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fn is_accepting(&self, _: &Self::Context) -> bool {
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matches!(self, Self::Ready)
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}
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}
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impl AirTplAggregate {
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pub(super) fn new() -> Self {
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Self::Ready
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}
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pub(super) fn active_tpl_oi(&self) -> Option<ObjectIndex<Tpl>> {
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use AirTplAggregate::*;
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match self {
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Ready => None,
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Toplevel(tplst) | TplMeta(tplst, _) | TplExpr(tplst, _) => {
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Some(tplst.oi())
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}
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}
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}
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/// Delegate to the expression parser [`AirExprAggregate`].
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fn delegate_expr(
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asg: &mut <Self as ParseState>::Context,
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tpl: TplState,
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expr: AirExprAggregateStoreDangling,
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etok: impl Into<<AirExprAggregateStoreDangling as ParseState>::Token>,
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) -> TransitionResult<Self> {
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let tok = etok.into();
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expr.parse_token(tok, asg).branch_dead::<Self, _>(
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|_, ()| Transition(Self::Toplevel(tpl)).incomplete(),
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|expr, result, ()| {
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result
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.map(ParseStatus::reflexivity)
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.transition(Self::TplExpr(tpl, expr))
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},
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(),
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)
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}
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}
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#[cfg(test)]
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mod test;
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