feat: add no_std + alloc support behind std feature gate

Cargo.toml

@@ -11,18 +11,19 @@ repository = "https://github.com/egraphs-good/egg"
 version = "0.11.0"
 
 [dependencies]
-env_logger = {version = "0.9.0", default-features = false}
-hashbrown = "0.15.2"
-indexmap = "2.7.0"
-log = "0.4.17"
-num-bigint = "0.4"
-num-traits = "0.2"
-quanta = "0.12"
-rustc-hash = "2.0.0"
+env_logger = {version = "0.9.0", default-features = false, optional = true}
+hashbrown = {version = "0.15.2", default-features = false}
+indexmap = {version = "2.7.0", default-features = false}
+log = {version = "0.4.17", default-features = false}
+num-bigint = {version = "0.4", default-features = false}
+num-traits = {version = "0.2", default-features = false}
+quanta = {version = "0.12", optional = true}
+rustc-hash = {version = "2.0.0", default-features = false}
 smallvec = {version = "1.8.0", features = ["union", "const_generics"]}
-symbol_table = {version = "0.4.0", features = ["global"]}
-symbolic_expressions = "5.0.3"
-thiserror = "1.0.31"
+spin = {version = "0.9", default-features = false, features = ["spin_mutex", "lazy"]}
+symbol_table = {git = "https://github.com/mwillsey/symbol_table", rev = "a716c39a4aa4757c910c93fc10c5c7fa8f467133", default-features = false, features = ["global"]}
+symbolic_expressions = {version = "5.0.3", optional = true}
+thiserror = "2"
 
 # for the lp feature
 good_lp = { version = "1", optional = true }
@@ -38,9 +39,22 @@ serde_json = {version = "1.0.81", optional = true}
 ordered-float = "3.0.0"
 
 [features]
+default = ["std"]
+std = [
+  "dep:env_logger",
+  "dep:quanta",
+  "dep:symbolic_expressions",
+  "hashbrown/default",
+  "indexmap/std",
+  "num-bigint/std",
+  "num-traits/std",
+  "log/std",
+  "rustc-hash/std",
+  "symbol_table/std",
+]
 # forces the use of indexmaps over hashmaps
 deterministic = []
-lp = ["good_lp"]
+lp = ["std", "good_lp"]
 reports = ["serde-1", "serde_json"]
 serde-1 = [
   "serde",
@@ -49,7 +63,7 @@ serde-1 = [
   "symbol_table/serde",
   "vectorize",
 ]
-wasm-bindgen = []
+wasm-bindgen = ["std"]
 
 # private features for testing
 test-explanations = []

Makefile

@@ -6,7 +6,9 @@ test:
 	cargo test --release --features=lp
 	# don't run examples in proof-production mode
 	cargo test --release --features "test-explanations"
-
+	# verify no_std build
+	cargo test --no-default-features
+
 
 .PHONY: nits
 nits:

src/dot.rs

@@ -8,7 +8,7 @@ Use the [`Dot`] struct to visualize an [`EGraph`]
 
 use std::ffi::OsStr;
 use std::fmt::{self, Debug, Display, Formatter};
-use std::io::{Error, ErrorKind, Result, Write};
+use std::io::{Error, Result, Write};
 use std::path::Path;
 
 use crate::{Analysis, Language, egraph::EGraph};
@@ -140,14 +140,11 @@ where
         write!(stdin, "{}", self)?;
         match child.wait()?.code() {
             Some(0) => Ok(()),
-            Some(e) => Err(Error::new(
-                ErrorKind::Other,
-                format!("dot program returned error code {}", e),
-            )),
-            None => Err(Error::new(
-                ErrorKind::Other,
-                "dot program was killed by a signal",
-            )),
+            Some(e) => Err(Error::other(format!(
+                "dot program returned error code {}",
+                e
+            ))),
+            None => Err(Error::other("dot program was killed by a signal")),
         }
     }
 

src/eclass.rs

@@ -1,5 +1,6 @@
-use std::fmt::Debug;
-use std::iter::ExactSizeIterator;
+use crate::no_std_prelude::*;
+use core::fmt::Debug;
+use core::iter::ExactSizeIterator;
 
 use crate::*;
 

src/egraph.rs

@@ -1,5 +1,6 @@
+use crate::no_std_prelude::*;
 use crate::*;
-use std::{
+use core::{
     borrow::BorrowMut,
     fmt::{self, Debug, Display},
     marker::PhantomData,
@@ -577,6 +578,7 @@ impl<L: Language, N: Analysis<L>> EGraph<L, N> {
     }
 
     /// Creates a [`Dot`] to visualize this egraph. See [`Dot`].
+    #[cfg(feature = "std")]
     pub fn dot(&self) -> Dot<'_, L, N> {
         Dot {
             egraph: self,
@@ -792,7 +794,7 @@ where
 }
 
 /// Given an `Id` using the `egraph[id]` syntax, retrieve the e-class.
-impl<L: Language, N: Analysis<L>> std::ops::Index<Id> for EGraph<L, N> {
+impl<L: Language, N: Analysis<L>> core::ops::Index<Id> for EGraph<L, N> {
     type Output = EClass<L, N::Data>;
     fn index(&self, id: Id) -> &Self::Output {
         let id = self.find(id);
@@ -804,7 +806,7 @@ impl<L: Language, N: Analysis<L>> std::ops::Index<Id> for EGraph<L, N> {
 
 /// Given an `Id` using the `&mut egraph[id]` syntax, retrieve a mutable
 /// reference to the e-class.
-impl<L: Language, N: Analysis<L>> std::ops::IndexMut<Id> for EGraph<L, N> {
+impl<L: Language, N: Analysis<L>> core::ops::IndexMut<Id> for EGraph<L, N> {
     fn index_mut(&mut self, id: Id) -> &mut Self::Output {
         let id = self.find_mut(id);
         self.classes
@@ -1144,7 +1146,7 @@ impl<L: Language, N: Analysis<L>> EGraph<L, N> {
     #[track_caller]
     pub fn union(&mut self, id1: Id, id2: Id) -> bool {
         if self.explain.is_some() {
-            let caller = std::panic::Location::caller();
+            let caller = core::panic::Location::caller();
             self.union_trusted(id1, id2, caller.to_string())
         } else {
             self.perform_union(id1, id2, None)
@@ -1158,18 +1160,18 @@ impl<L: Language, N: Analysis<L>> EGraph<L, N> {
         let mut id1 = self.find_mut(enode_id1);
         let mut id2 = self.find_mut(enode_id2);
         if id1 == id2 {
-            if let Some(Justification::Rule(_)) = rule {
-                if let Some(explain) = &mut self.explain {
-                    explain.alternate_rewrite(enode_id1, enode_id2, rule.unwrap());
-                }
+            if let Some(Justification::Rule(_)) = rule
+                && let Some(explain) = &mut self.explain
+            {
+                explain.alternate_rewrite(enode_id1, enode_id2, rule.unwrap());
             }
             return false;
         }
         // make sure class2 has fewer parents
         let class1_parents = self.classes[&id1].parents.len();
         let class2_parents = self.classes[&id2].parents.len();
         if class1_parents < class2_parents {
-            std::mem::swap(&mut id1, &mut id2);
+            core::mem::swap(&mut id1, &mut id2);
         }
 
         if let Some(explain) = &mut self.explain {
@@ -1180,6 +1182,7 @@ impl<L: Language, N: Analysis<L>> EGraph<L, N> {
         self.unionfind.union(id1, id2);
 
         assert_ne!(id1, id2);
+        #[allow(deprecated)]
         let class2 = self.classes.remove(&id2).unwrap();
         let class1 = self.classes.get_mut(&id1).unwrap();
         assert_eq!(id1, class1.id);
@@ -1232,10 +1235,10 @@ impl<L: Language + Display, N: Analysis<L>> EGraph<L, N> {
     /// Useful for testing.
     pub fn check_goals(&self, id: Id, goals: &[Pattern<L>]) {
         let (cost, best) = Extractor::new(self, AstSize).find_best(id);
-        println!("End ({}): {}", cost, best.pretty(80));
+        log::info!("End ({}): {}", cost, best.pretty(80));
 
         for (i, goal) in goals.iter().enumerate() {
-            println!("Trying to prove goal {}: {}", i, goal.pretty(40));
+            log::info!("Trying to prove goal {}: {}", i, goal.pretty(40));
             let matches = goal.search_eclass(self, id);
             if matches.is_none() {
                 let best = Extractor::new(self, AstSize).find_best(id).1;
@@ -1257,7 +1260,7 @@ impl<L: Language + Display, N: Analysis<L>> EGraph<L, N> {
 impl<L: Language, N: Analysis<L>> EGraph<L, N> {
     #[inline(never)]
     fn rebuild_classes(&mut self) -> usize {
-        let mut classes_by_op = std::mem::take(&mut self.classes_by_op);
+        let mut classes_by_op = core::mem::take(&mut self.classes_by_op);
         classes_by_op.values_mut().for_each(|ids| ids.clear());
 
         let mut trimmed = 0;
@@ -1398,7 +1401,6 @@ impl<L: Language, N: Analysis<L>> EGraph<L, N> {
     /// let y = egraph.add(S::leaf("y"));
     /// let ax = egraph.add_expr(&"(+ a x)".parse().unwrap());
     /// let ay = egraph.add_expr(&"(+ a y)".parse().unwrap());
-
     /// // Union x and y
     /// egraph.union(x, y);
     /// // Classes: [x y] [ax] [ay] [a]
@@ -1467,7 +1469,7 @@ impl<'a, L: Language, N: Analysis<L>> Debug for EGraphDump<'a, L, N> {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, feature = "std"))]
 mod tests {
 
     use super::*;