Real working version!

python/egglog/exp/program_gen.py

@@ -165,16 +165,19 @@ def _compile(
     # of the two
     program_add = p1 + p2
 
-    # Set parents
-    yield rule(eq(p).to(program_add), p.compile(i)).then(set_(p1.parent).to(p), set_(p2.parent).to(p))
+    # Set parent of p1
+    yield rule(eq(p).to(program_add), p.compile(i)).then(set_(p1.parent).to(p))
 
-    # Compile p1, if p1 parent set
+    # Compile p1, if p1 parent equal
     yield rule(eq(p).to(program_add), p.compile(i), eq(p1.parent).to(program_add)).then(p1.compile(i))
 
-    # Compile p2, if p1 parent not set
+    # Set parent of p2, once p1 compiled
+    yield rule(eq(p).to(program_add), p1.next_sym).then(set_(p2.parent).to(p))
+
+    # Compile p2, if p1 parent not equal
     yield rule(eq(p).to(program_add), p.compile(i), p1.parent != p).then(p2.compile(i))
 
-    # Compile p2, if p1 parent set
+    # Compile p2, if p1 parent eqal
     yield rule(eq(p).to(program_add), eq(p1.parent).to(program_add), eq(i).to(p1.next_sym)).then(p2.compile(i))
 
     # Set p expr to join of p1 and p2

python/tests/__snapshots__/test_program_gen/test_to_string.py

@@ -1,4 +1,6 @@
-_0 = -(x)
+_0 = -x
 assert _0 > 0
 _1 = _0 + x
-_1
+_2 = _1 + 2
+_3 = _2 + _1
+_3

python/tests/test_program_gen.py

@@ -51,19 +51,19 @@ def _rules(
         yield rewrite(Math(i).program).to(Program(i.to_string()))
         yield rewrite((y + z).program).to((y.program + " + " + z.program).assign())
         yield rewrite((y * z).program).to((y.program + " * " + z.program).assign())
-        yield rewrite((-y).program).to(Program("-(") + y.program + ")")
+        yield rewrite((-y).program).to(Program("-") + y.program)
         assigned_x = x.program.assign()
         yield rewrite(assume_pos(x).program).to(assigned_x.statement(Program("assert ") + assigned_x + " > 0"))
 
     first = assume_pos(-Math.var("x")) + Math.var("x")
     with egraph:
-        y = first
+        y = first + Math(2) + first
         egraph.register(y.program)
-        egraph.run(10)
+        egraph.run(100)
         p = egraph.extract(y.program)
     egraph.register(p)
     egraph.register(p.compile())
-    egraph.run(40)
+    egraph.run(100)
     # egraph.display(n_inline_leaves=1)
     e = egraph.load_object(egraph.extract(PyObject.from_string(p.expr)))
     stmts = egraph.load_object(egraph.extract(PyObject.from_string(p.statements)))