fix of yihong's review

dag_in_context/src/pretty_print.rs

@@ -1,3 +1,9 @@
+// behaviors: the pretty printer take an RcExpr and return a log with folded top level Expr at the end and folded children
+// of top level Expr before it.
+// limitations:
+// if two similar expr have different context, the to rust pretty printer will still print two expr
+// when to rust, print to parallel!/switch! might not produce the optimal looking thing
+
 use crate::{
     from_egglog::FromEgglog,
     prologue,
@@ -182,8 +188,13 @@ impl PrettyPrinter {
             .iter()
             .map(|fresh_var| {
                 let node = self.table.get(fresh_var).unwrap();
-                let ast = node.ast_node_to_str(true);
-                format!("let {fresh_var} = {ast};")
+                match node {
+                    AstNode::Assumption(_) => String::new(),
+                    _ => {
+                        let ast = node.ast_node_to_str(true);
+                        format!("let {fresh_var} = {ast};")
+                    }
+                }
             })
             .collect::<Vec<_>>()
             .join("\n");
@@ -315,6 +326,8 @@ impl PrettyPrinter {
                     }
                 }
                 Expr::Symbolic(_) => panic!("Expected non symbolic"),
+                Expr::Concat(..) | Expr::Single(..) if to_rust => expr
+                    .map_expr_children(|e| self.refactor_shared_expr(e, fold_when, to_rust, log)),
                 _ => {
                     let expr2 = expr.map_expr_type(|ty| self.refactor_shared_type(ty, log));
                     let expr3 = expr2.map_expr_assum(|assum| {

dag_in_context/src/schema_helpers.rs

@@ -274,6 +274,8 @@ impl Expr {
         }
     }
 
+    // this function might violate RcExpr's invariant
+    // for example function map_child is id function that create new RcExpr, and &self have two same children
     pub fn map_expr_children<F>(self: &RcExpr, mut map_child: F) -> RcExpr
     where
         F: FnMut(&RcExpr) -> RcExpr,

dag_in_context/src/snapshots/dag_in_context__pretty_print__pretty_print.snap

@@ -3,40 +3,23 @@ source: src/pretty_print.rs
 expression: ast
 ---
 let tpl_s_v0 = tuplet!(statet());
-let in_func_v1 = infunc("dummy");
-let concat_v2 = parallel!(int(4), getat(0));
-let concat_v3 = concat(single(int(2)), 
-concat(single(int(3)), 
-concat_v2.clone()));
-let less_than_v4 = less_than(getat(0), 
+
+let less_than_v2 = less_than(getat(0), 
 getat(3));
-let single_v5 = single(getat(0));
-let single_v6 = single(getat(1));
-let single_v7 = single(getat(2));
-let single_v8 = single(getat(3));
-let sub_v9 = sub(getat(2), 
+let sub_v3 = sub(getat(2), 
 getat(1));
-let tprint_v10 = tprint(sub_v9.clone(), 
+let tprint_v4 = tprint(sub_v3.clone(), 
 getat(4));
-let concat_v11 = concat(concat(single(less_than_v4.clone()), 
-concat(single_v5.clone(), 
-single_v6.clone())), 
-concat(concat(single_v7.clone(), 
-single_v8.clone()), 
-single(tprint_v10.clone())));
-let tpl__v12 = emptyt();
-let tpl_i_v13 = tuplet!(intt());
-let in_func_v14 = infunc(" loop_ctx_0");
-let less_than_v15 = less_than(getat(0), 
+let dowhile_v5 = dowhile(parallel!(int(1), int(2), int(3), int(4), getat(0)), 
+parallel!(less_than_v2.clone(), getat(0), getat(1), getat(2), getat(3), tprint_v4.clone()));
+let tpl__v6 = emptyt();
+let tpl_i_v7 = tuplet!(intt());
+
+let less_than_v9 = less_than(getat(0), 
 int(3));
-let in_switch_v16 = inswitch(0, 
-int(0), 
-arg());
-let switch_v17 = switch!(int(0), arg(); parallel!(int(4), int(5)));
-let dowhile_v18 = dowhile(single(int(1)), 
-parallel!(less_than_v15.clone(), get(switch_v17.clone(), 0)));
-let concat_v19 = concat(dowhile(concat(single(int(1)), 
-concat_v3.clone()), 
-concat_v11.clone()), 
-dowhile_v18.clone());
-let concat_v20 = concat_v19.clone();
+
+let switch_v11 = switch!(int(0), arg(); parallel!(int(4), int(5)));
+let dowhile_v12 = dowhile(single(int(1)), 
+parallel!(less_than_v9.clone(), get(switch_v11.clone(), 0)));
+let concat_v13 = concat(dowhile_v5.clone(), 
+dowhile_v12.clone());