all: split reusable components into workspace crates

criteria/src/crit_matchers/critm_constant.rs

@@ -0,0 +1,58 @@
+use {
+    crate::{
+        CritMatcherIds, FixedRootMatcher,
+        crit_graph::{
+            CritFixedRootCriterion, CritFixedRootCriterionBase, CritMgr, CritRoot, CritRootFixed,
+            CritTarget,
+        },
+    },
+    linearize::static_map,
+    std::{marker::PhantomData, rc::Rc},
+};
+
+pub struct CritMatchConstant<Target>(pub bool, pub PhantomData<fn(&Target)>);
+
+impl<Target> CritMatchConstant<Target>
+where
+    Target: CritTarget,
+{
+    pub fn create(
+        roots: &Rc<Target::RootMatchers>,
+        ids: &CritMatcherIds,
+    ) -> FixedRootMatcher<Target, CritMatchConstant<Target>> {
+        static_map! {
+            v => CritRoot::new(
+                roots,
+                ids.next(),
+                CritRootFixed(Self(v, PhantomData), PhantomData),
+            ),
+        }
+    }
+}
+
+impl<Target> CritFixedRootCriterionBase<Target> for CritMatchConstant<Target>
+where
+    Target: CritTarget,
+{
+    fn constant(&self) -> bool {
+        self.0
+    }
+
+    fn not<'a>(&self, mgr: &'a Target::Mgr) -> &'a FixedRootMatcher<Target, Self>
+    where
+        Self: CritFixedRootCriterion<Target>,
+    {
+        mgr.match_constant()
+    }
+}
+
+impl<Target> CritFixedRootCriterion<Target> for CritMatchConstant<Target>
+where
+    Target: CritTarget,
+{
+    const COMPARE: bool = false;
+
+    fn matches(&self, _data: &Target) -> bool {
+        self.0
+    }
+}