tamer: nir::air: Dynamic configuration in place of static wip-asg-derived-xmli flag

This flag should have never been sprinkled here; it makes the system much
harder to understand.

But, this is working toward a command-line tamec option to toggle NIR
lowering on/off for various packages.

DEV-13162

tamer/src/bin/tamec.rs

@@ -43,6 +43,7 @@ use tamer::{
     diagnose::{
         AnnotatedSpan, Diagnostic, FsSpanResolver, Reporter, VisualReporter,
     },
+    nir::NirToAirParseType,
     parse::{lowerable, FinalizeError, ParseError, Token},
     pipeline::{parse_package_xml, LowerXmliError, ParsePackageXmlError},
     xir::{self, reader::XmlXirReader, DefaultEscaper},
@@ -137,11 +138,17 @@ fn compile<R: Reporter>(
         }
     }));
 
+    #[cfg(not(feature = "wip-asg-derived-xmli"))]
+    let parse_type = NirToAirParseType::Noop;
+    #[cfg(feature = "wip-asg-derived-xmli")]
+    let parse_type = NirToAirParseType::LowerKnownErrorRest;
+
     // TODO: Determine a good default capacity once we have this populated
     //   and can come up with some heuristics.
-    let (air_ctx,) = parse_package_xml(DefaultAsg::with_capacity(1024, 2048))(
-        src, report_err,
-    )?;
+    let (_, air_ctx) = parse_package_xml(
+        parse_type,
+        DefaultAsg::with_capacity(1024, 2048),
+    )(src, report_err)?;
 
     match reporter.has_errors() {
         false => {

tamer/src/nir.rs

@@ -72,7 +72,7 @@ use std::{
     fmt::{Debug, Display},
 };
 
-pub use air::{NirToAir, NirToAirError};
+pub use air::{NirToAir, NirToAirError, NirToAirParseType};
 pub use interp::{InterpError, InterpState as InterpolateNir};
 pub use parse::{
     NirParseState as XirfToNir, NirParseStateError_ as XirfToNirError,

tamer/src/nir/air.rs

@@ -21,22 +21,58 @@
 
 use super::Nir;
 use crate::{
-    asg::air::Air,
+    asg::{air::Air, ExprOp},
     diagnose::{Annotate, Diagnostic},
     fmt::{DisplayWrapper, TtQuote},
+    nir::{Nir::*, NirEntity::*},
     parse::prelude::*,
     span::Span,
+    sym::{st::raw::U_TRUE, SymbolId},
 };
 use arrayvec::ArrayVec;
 use std::{error::Error, fmt::Display};
 
-// These are also used by the `test` module which imports `super`.
-#[cfg(feature = "wip-asg-derived-xmli")]
-use crate::{
-    asg::ExprOp,
-    nir::{Nir::*, NirEntity::*},
-    sym::{st::raw::U_TRUE, SymbolId},
-};
+/// Dynamic [`NirToAir`] parser configuration.
+///
+/// This acts as a runtime feature flag while this portions of TAMER is
+///   under development.
+#[derive(Debug, PartialEq, Eq)]
+pub enum NirToAirParseType {
+    /// Discard incoming tokens instead of lowering them.
+    Noop,
+
+    /// Lower known tokens,
+    ///   but produce errors for everything else that is not yet supported.
+    ///
+    /// It is expected that this will fail on at least some packages;
+    ///   this should be enabled only on packages known to compile with the
+    ///   new system.
+    LowerKnownErrorRest,
+}
+
+impl Display for NirToAirParseType {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        match self {
+            Self::Noop => write!(f, "discarding all tokens (noop)"),
+            Self::LowerKnownErrorRest => write!(
+                f,
+                "lowering only supported tokens and failing on all others"
+            ),
+        }
+    }
+}
+
+impl From<NirToAirParseType> for (NirToAirParseType, ObjStack) {
+    fn from(ty: NirToAirParseType) -> Self {
+        (ty, Default::default())
+    }
+}
+
+impl From<(NirToAirParseType, ObjStack)> for NirToAirParseType {
+    fn from((ty, _): (NirToAirParseType, ObjStack)) -> Self {
+        ty
+    }
+}
 
 #[derive(Debug, PartialEq, Eq, Default)]
 pub enum NirToAir {
@@ -78,36 +114,28 @@ type ObjStack = ArrayVec<Air, 2>;
 
 /// The symbol to use when lexically expanding shorthand notations to
 ///   compare against values of `1`.
-#[cfg(feature = "wip-asg-derived-xmli")]
 pub const SYM_TRUE: SymbolId = U_TRUE;
 
 impl ParseState for NirToAir {
     type Token = Nir;
     type Object = Air;
     type Error = NirToAirError;
-    type Context = ObjStack;
+    type Context = (NirToAirParseType, ObjStack);
+    type PubContext = NirToAirParseType;
 
-    #[cfg(not(feature = "wip-asg-derived-xmli"))]
     fn parse_token(
         self,
         tok: Self::Token,
-        _queue: &mut Self::Context,
-    ) -> TransitionResult<Self::Super> {
-        use NirToAir::*;
-
-        let _ = tok; // prevent `unused_variables` warning
-        Transition(Ready).ok(Air::Todo(crate::span::UNKNOWN_SPAN))
-    }
-
-    #[cfg(feature = "wip-asg-derived-xmli")]
-    fn parse_token(
-        self,
-        tok: Self::Token,
-        stack: &mut Self::Context,
+        (parse_type, stack): &mut Self::Context,
     ) -> TransitionResult<Self::Super> {
         use NirToAir::*;
         use NirToAirError::*;
 
+        match parse_type {
+            NirToAirParseType::Noop => return Transition(Ready).incomplete(),
+            NirToAirParseType::LowerKnownErrorRest => (),
+        }
+
         if let Some(obj) = stack.pop() {
             return Transition(Ready).ok(obj).with_lookahead(tok);
         }
@@ -284,7 +312,7 @@ impl ParseState for NirToAir {
         }
     }
 
-    fn is_accepting(&self, stack: &Self::Context) -> bool {
+    fn is_accepting(&self, (_, stack): &Self::Context) -> bool {
         matches!(self, Self::Ready) && stack.is_empty()
     }
 }
@@ -364,5 +392,5 @@ impl Diagnostic for NirToAirError {
     }
 }
 
-#[cfg(all(test, feature = "wip-asg-derived-xmli"))]
+#[cfg(test)]
 mod test;

tamer/src/nir/air/test.rs

@@ -18,12 +18,33 @@
 //  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 use super::*;
-use crate::{parse::util::SPair, span::dummy::*};
+use crate::{
+    parse::{util::SPair, Parser},
+    span::dummy::*,
+};
 
 type Sut = NirToAir;
 
 use Parsed::{Incomplete, Object as O};
 
+fn sut_parse<I: Iterator<Item = Nir>>(toks: I) -> Parser<Sut, I> {
+    Sut::parse_with_context(
+        toks.into_iter(),
+        NirToAirParseType::LowerKnownErrorRest,
+    )
+}
+
+#[test]
+fn ignores_input_when_parse_type_is_noop() {
+    let toks = vec![Open(Package, S1), Close(Package, S2)];
+
+    assert_eq!(
+        Ok(vec![Incomplete, Incomplete,]),
+        Sut::parse_with_context(toks.into_iter(), NirToAirParseType::Noop)
+            .collect(),
+    );
+}
+
 #[test]
 fn package_to_pkg() {
     let toks = vec![Open(Package, S1), Close(Package, S2)];
@@ -33,7 +54,7 @@ fn package_to_pkg() {
             O(Air::PkgStart(S1, SPair("/TODO".into(), S1))),
             O(Air::PkgEnd(S2)),
         ]),
-        Sut::parse(toks.into_iter()).collect(),
+        sut_parse(toks.into_iter()).collect(),
     );
 }
 
@@ -55,7 +76,7 @@ fn rate_to_sum_expr() {
               O(Air::BindIdent(id)),
             O(Air::ExprEnd(S3)),
         ]),
-        Sut::parse(toks.into_iter()).collect(),
+        sut_parse(toks.into_iter()).collect(),
     );
 }
 
@@ -77,7 +98,7 @@ fn calc_exprs() {
               O(Air::ExprEnd(S3)),
             O(Air::ExprEnd(S4)),
         ]),
-        Sut::parse(toks.into_iter()).collect(),
+        sut_parse(toks.into_iter()).collect(),
     );
 }
 
@@ -99,7 +120,7 @@ fn classify_to_conj_expr() {
               O(Air::BindIdent(id)),
             O(Air::ExprEnd(S3)),
         ]),
-        Sut::parse(toks.into_iter()).collect(),
+        sut_parse(toks.into_iter()).collect(),
     );
 }
 
@@ -121,7 +142,7 @@ fn logic_exprs() {
               O(Air::ExprEnd(S3)),
             O(Air::ExprEnd(S4)),
         ]),
-        Sut::parse(toks.into_iter()).collect(),
+        sut_parse(toks.into_iter()).collect(),
     );
 }
 
@@ -148,7 +169,7 @@ fn desc_as_indep_clause() {
               O(Air::DocIndepClause(desc)),
             O(Air::ExprEnd(S4)),
         ]),
-        Sut::parse(toks.into_iter()).collect(),
+        sut_parse(toks.into_iter()).collect(),
     );
 }
 
@@ -170,7 +191,7 @@ fn tpl_with_name() {
               O(Air::BindIdent(name)),
             O(Air::TplEnd(S3)),
         ]),
-        Sut::parse(toks.into_iter()).collect(),
+        sut_parse(toks.into_iter()).collect(),
     );
 }
 
@@ -194,7 +215,7 @@ fn apply_template_long_form_nullary() {
               O(Air::RefIdent(name)),
             O(Air::TplEndRef(S3)),
         ]),
-        Sut::parse(toks.into_iter()).collect(),
+        sut_parse(toks.into_iter()).collect(),
     );
 }
 
@@ -240,7 +261,7 @@ fn apply_template_long_form_args() {
               O(Air::MetaEnd(S10)),
             O(Air::TplEndRef(S11)),
         ]),
-        Sut::parse(toks.into_iter()).collect(),
+        sut_parse(toks.into_iter()).collect(),
     );
 }
 
@@ -274,7 +295,7 @@ fn match_short_no_value() {
             O(Air::RefIdent(SPair(SYM_TRUE, S1))),
             O(Air::ExprEnd(S3)),
         ]),
-        Sut::parse(toks.into_iter()).collect(),
+        sut_parse(toks.into_iter()).collect(),
     );
 }
 
@@ -306,7 +327,7 @@ fn match_short_with_value() {
             O(Air::RefIdent(value)),
             O(Air::ExprEnd(S4)),
         ]),
-        Sut::parse(toks.into_iter()).collect(),
+        sut_parse(toks.into_iter()).collect(),
     );
 }
 
@@ -345,7 +366,7 @@ fn match_short_value_before_subject_err() {
             Ok(O(Air::RefIdent(SPair(SYM_TRUE, S1)))),
             Ok(O(Air::ExprEnd(S3))),
         ],
-        Sut::parse(toks.into_iter()).collect::<Vec<Result<_, _>>>(),
+        sut_parse(toks.into_iter()).collect::<Vec<Result<_, _>>>(),
     );
 }
 
@@ -370,7 +391,7 @@ fn match_no_args_err() {
             )),
             // RECOVERY: Useless match above discarded.
         ],
-        Sut::parse(toks.into_iter()).collect::<Vec<Result<_, _>>>(),
+        sut_parse(toks.into_iter()).collect::<Vec<Result<_, _>>>(),
     );
 }
 
@@ -395,6 +416,6 @@ fn text_as_arbitrary_doc() {
             O(Air::DocText(text)),
           O(Air::PkgEnd(S3)),
         ]),
-        Sut::parse(toks.into_iter()).collect(),
+        sut_parse(toks.into_iter()).collect(),
     );
 }

tamer/src/pipeline.rs

@@ -152,7 +152,7 @@ lower_pipeline! {
         |> XirfToNir
         |> TplShortDesugar
         |> InterpolateNir
-        |> NirToAir
+        |> NirToAir[nir_air_ty]
         |> AirAggregate[air_ctx];
 
     /// Lower an [`Asg`](crate::asg::Asg)-derived token stream into an