diff --git a/tools/egraphs-cond-synth/src/main.rs b/tools/egraphs-cond-synth/src/main.rs
index a7148db..12a9b6b 100644
--- a/tools/egraphs-cond-synth/src/main.rs
+++ b/tools/egraphs-cond-synth/src/main.rs
@@ -6,16 +6,16 @@
 // author: Mohanna Shahrad <mohanna@princeton.edu>
 
 mod features;
+mod rewrites;
 mod samples;
 mod summarize;
 
 use crate::features::apply_features;
+use crate::rewrites::create_rewrites;
 use crate::samples::{get_rule_info, Samples};
 use crate::summarize::bdd_summarize;
 use clap::Parser;
-use egg::*;
 use patronus::expr::*;
-use patronus_egraphs::*;
 use std::path::PathBuf;
 
 #[derive(Parser, Debug)]
@@ -43,86 +43,15 @@ struct Args {
         help = "read assignments from a JSON file instead of generating and checking them"
     )]
     read_assignments: Option<PathBuf>,
+    #[arg(
+        long,
+        help = "writes assignments, features and equivalence into a CSV table"
+    )]
+    write_csv: Option<PathBuf>,
     #[arg(value_name = "RULE", index = 1)]
     rule: String,
 }
 
-/// our version of the egg re-write macro
-macro_rules! arith_rewrite {
-    (
-        $name:expr;
-        $lhs:expr => $rhs:expr;
-        if $cond:expr
-    ) => {{
-        ArithRewrite::new($name, $lhs, $rhs)
-    }};
-}
-
-struct ArithRewrite {
-    name: String,
-    lhs: Pattern<Arith>,
-    rhs: Pattern<Arith>,
-}
-
-impl ArithRewrite {
-    fn new(name: &str, lhs: &str, rhs: &str) -> Self {
-        Self {
-            name: name.to_string(),
-            lhs: lhs.parse::<_>().unwrap(),
-            rhs: rhs.parse::<_>().unwrap(),
-        }
-    }
-
-    fn to_egg(&self) -> Rewrite<Arith, ()> {
-        Rewrite::new(self.name.clone(), self.lhs.clone(), self.rhs.clone()).unwrap()
-    }
-}
-
-fn create_rewrites() -> Vec<Rewrite<Arith, ()>> {
-    let rewrites = vec![
-        arith_rewrite!("commute-add"; "(+ ?wo ?wa ?sa ?a ?wb ?sb ?b)" => "(+ ?wo ?wb ?sb ?b ?wa ?sa ?a)"; if true),
-        arith_rewrite!("merge-left-shift";
-            // we require that b, c and (b + c) are all unsigned
-            "(<< ?wo ?wab ?sab (<< ?wab ?wa ?sa ?a ?wb 0 ?b) ?wc 0 ?c)" =>
-            // note: in this version we set the width of (b + c) on the RHS to be the width of the
-            //       result (w_o)
-            "(<< ?wo ?wa ?sa ?a ?wo 0 (+ ?wo ?wb 0 ?b ?wc 0 ?c))"; if merge_left_shift_cond("?wo", "?wa", "?sa", "?wb", "?wc")),
-    ];
-    rewrites.into_iter().map(|r| r.to_egg()).collect()
-}
-
-type EGraph = egg::EGraph<Arith, ()>;
-
-fn merge_left_shift_cond(
-    wo: &'static str,
-    wa: &'static str,
-    sa: &'static str,
-    wb: &'static str,
-    wc: &'static str,
-) -> impl Fn(&mut EGraph, Id, &Subst) -> bool {
-    let wo = wo.parse().unwrap();
-    let wa = wa.parse().unwrap();
-    let sa = sa.parse().unwrap();
-    let wb = wb.parse().unwrap();
-    let wc = wc.parse().unwrap();
-    move |egraph, _, subst| {
-        let wo = get_width_from_e_graph(egraph, subst, wo);
-        let wa = get_width_from_e_graph(egraph, subst, wa);
-        let sa = get_width_from_e_graph(egraph, subst, sa);
-        let wb = get_width_from_e_graph(egraph, subst, wb);
-        let wc = get_width_from_e_graph(egraph, subst, wc);
-        // actual condition
-        wa == wb && wo >= wa
-    }
-}
-
-fn get_width_from_e_graph(egraph: &mut EGraph, subst: &Subst, v: Var) -> WidthInt {
-    match egraph[subst[v]].nodes.as_slice() {
-        [Arith::WidthConst(w)] => *w,
-        _ => unreachable!("expected a width!"),
-    }
-}
-
 fn main() {
     let args = Args::parse();
 
diff --git a/tools/egraphs-cond-synth/src/rewrites.rs b/tools/egraphs-cond-synth/src/rewrites.rs
new file mode 100644
index 0000000..d769379
--- /dev/null
+++ b/tools/egraphs-cond-synth/src/rewrites.rs
@@ -0,0 +1,83 @@
+// Copyright 2024 Cornell University
+// released under BSD 3-Clause License
+// author: Kevin Laeufer <laeufer@cornell.edu>
+
+use egg::*;
+use patronus::expr::*;
+use patronus_egraphs::*;
+
+/// our version of the egg re-write macro
+macro_rules! arith_rewrite {
+    (
+        $name:expr;
+        $lhs:expr => $rhs:expr;
+        if $cond:expr
+    ) => {{
+        ArithRewrite::new($name, $lhs, $rhs)
+    }};
+}
+
+struct ArithRewrite {
+    name: String,
+    lhs: Pattern<Arith>,
+    rhs: Pattern<Arith>,
+}
+
+impl ArithRewrite {
+    fn new(name: &str, lhs: &str, rhs: &str) -> Self {
+        Self {
+            name: name.to_string(),
+            lhs: lhs.parse::<_>().unwrap(),
+            rhs: rhs.parse::<_>().unwrap(),
+        }
+    }
+
+    fn to_egg(&self) -> Rewrite<Arith, ()> {
+        Rewrite::new(self.name.clone(), self.lhs.clone(), self.rhs.clone()).unwrap()
+    }
+}
+
+pub fn create_rewrites() -> Vec<Rewrite<Arith, ()>> {
+    let rewrites = vec![
+        arith_rewrite!("commute-add"; "(+ ?wo ?wa ?sa ?a ?wb ?sb ?b)" => "(+ ?wo ?wb ?sb ?b ?wa ?sa ?a)"; if true),
+        arith_rewrite!("merge-left-shift";
+            // we require that b, c and (b + c) are all unsigned
+            "(<< ?wo ?wab ?sab (<< ?wab ?wa ?sa ?a ?wb 0 ?b) ?wc 0 ?c)" =>
+            // note: in this version we set the width of (b + c) on the RHS to be the width of the
+            //       result (w_o)
+            "(<< ?wo ?wa ?sa ?a ?wo 0 (+ ?wo ?wb 0 ?b ?wc 0 ?c))"; if merge_left_shift_cond("?wo", "?wa", "?sa", "?wb", "?wc")),
+    ];
+    rewrites.into_iter().map(|r| r.to_egg()).collect()
+}
+
+type EGraph = egg::EGraph<Arith, ()>;
+
+fn merge_left_shift_cond(
+    wo: &'static str,
+    wa: &'static str,
+    sa: &'static str,
+    wb: &'static str,
+    wc: &'static str,
+) -> impl Fn(&mut EGraph, Id, &Subst) -> bool {
+    let wo = wo.parse().unwrap();
+    let wa = wa.parse().unwrap();
+    let sa = sa.parse().unwrap();
+    let wb = wb.parse().unwrap();
+    let wc = wc.parse().unwrap();
+    move |egraph, _, subst| {
+        let wo = get_width_from_e_graph(egraph, subst, wo);
+        let wa = get_width_from_e_graph(egraph, subst, wa);
+        let sa = get_width_from_e_graph(egraph, subst, sa);
+        let wb = get_width_from_e_graph(egraph, subst, wb);
+        let wc = get_width_from_e_graph(egraph, subst, wc);
+        // actual condition
+        wa == wb && wo >= wa
+    }
+}
+
+fn get_width_from_e_graph(egraph: &mut EGraph, subst: &Subst, v: Var) -> WidthInt {
+    match egraph[subst[v]].nodes.as_slice() {
+        [Arith::WidthConst(w)] => *w,
+        _ => unreachable!("expected a width!"),
+    }
+}