add ability to filter tags

src/compression.rs

@@ -223,7 +223,27 @@ pub struct CompressionStepConfig {
     /// Silence all printing within a compression step. See `silent` to silence all outputs between compression steps as well.
     #[clap(long)]
     pub quiet: bool,
-
+
+    // Fused lambda tags
+    #[clap(long, value_parser = clap::value_parser!(FusedLambdaTags), default_value="")]
+    pub fused_lambda_tags: FusedLambdaTags,
+}
+
+#[derive(Debug, Clone, Serialize)]
+pub struct FusedLambdaTags {
+    tags: Option<FxHashSet<Tag>>,
+}
+
+// parse from a string like "1,2,3"
+impl std::str::FromStr for FusedLambdaTags {
+    type Err = String;
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if s.is_empty() {
+            return Ok(FusedLambdaTags { tags: None })
+        }
+        let tags = s.split(",").map(|s| s.parse::<Tag>().unwrap()).collect();
+        Ok(FusedLambdaTags { tags: Some(tags) })
+    }
 }
 
 impl CompressionStepConfig {
@@ -373,6 +393,12 @@ impl Pattern {
                 }
             }
         }
+
+        match_locations.retain(|node|
+            !invalid_match_location(set,
+                                    &cfg.fused_lambda_tags.tags,
+                                    *node)
+        );
 
         if cfg.eta_long {
 
@@ -659,6 +685,26 @@ pub struct SharedData {
     pub cfg: CompressionStepConfig,
     pub multistep_cfg: MultistepCompressionConfig,
     pub tracking: Option<Tracking>,
+    pub fused_lambda_tags: Option<FxHashSet<Tag>>,
+}
+
+fn invalid_metavar_location(shared : &Arc<SharedData>, node: Idx) -> bool {
+    fused_lambda_location(&shared.set, &shared.fused_lambda_tags, node)
+}
+
+fn invalid_match_location(set : &ExprSet, fused_lambda_tags: &Option<FxHashSet<Tag>>, node: Idx) -> bool {
+    fused_lambda_location(set, fused_lambda_tags, node)
+}
+
+fn fused_lambda_location(set : &ExprSet, fused_lambda_tags: &Option<FxHashSet<Tag>>, node: Idx) -> bool {
+    if let Some(fused_lambda_tags) = fused_lambda_tags {
+        if let Node::Lam(_, tag) = &set[node] {
+            if fused_lambda_tags.contains(tag) {
+                return true
+            }
+        }
+    }
+    false
 }
 
 /// Used for debugging tracking information
@@ -1166,16 +1212,19 @@ fn get_ivars_expansions(original_pattern: &Pattern, arg_of_loc: &FxHashMap<Idx,A
     for ivar in 0..original_pattern.first_zid_of_ivar.len() {
         let arg_of_loc_ivar = &shared.arg_of_zid_node[original_pattern.first_zid_of_ivar[ivar]];
         let locs: Vec<Idx> = original_pattern.match_locations.iter()
-            .filter(|loc|
+            .filter(|loc:&&Idx|
                 arg_of_loc[loc].shifted_id == 
-                arg_of_loc_ivar[loc].shifted_id).cloned().collect();
+                arg_of_loc_ivar[loc].shifted_id
+                && !invalid_metavar_location(shared, arg_of_loc[loc].shifted_id)
+            ).cloned().collect();
         if locs.is_empty() { continue; }
         ivars_expansions.push((ExpandsTo::IVar(ivar as i32), locs));
     }
     // also consider one ivar greater, if this is within the arity limit. This will match at all the same locations as the original.
     if original_pattern.first_zid_of_ivar.len() < shared.cfg.max_arity {
         let ivar = original_pattern.first_zid_of_ivar.len();
-        let locs = original_pattern.match_locations.clone();
+        let mut locs = original_pattern.match_locations.clone();
+        locs.retain(|loc| !invalid_metavar_location(shared, arg_of_loc[loc].shifted_id));
         ivars_expansions.push((ExpandsTo::IVar(ivar as i32), locs));
     }
     ivars_expansions
@@ -2085,6 +2134,15 @@ pub fn compression_step(
     worklist.push(HeapItem::new(single_hole));
 
     let crit = CriticalMultithreadData::new(donelist, worklist, cfg);
+
+    let fused_copy: Option<FxHashSet<Tag>> = if let Some(fused_tags) = &cfg.fused_lambda_tags.tags {
+        let mut fused_copy = FxHashSet::default();
+        fused_copy.extend(fused_tags.iter().cloned());
+        Some(fused_copy)
+    } else {
+        None
+    };
+
     let shared = Arc::new(SharedData {
         crit: Mutex::new(crit),
         programs: programs.to_vec(),
@@ -2117,6 +2175,7 @@ pub fn compression_step(
         cfg: cfg.clone(),
         multistep_cfg: multistep_cfg.clone(),
         tracking,
+        fused_lambda_tags: fused_copy,
     });
 
     if !shared.cfg.quiet { println!("built SharedData: {:?}ms", tstart.elapsed().as_millis()) }