Realize lazy seqs when checking if they are empty (#182)

Author: chrisrink10

basilisp/lang/seq.py

@@ -182,7 +182,8 @@ def _realize(self):
     @property
     def is_empty(self) -> bool:
         if not self._realized:
-            return False
+            self._realize()
+            return self.is_empty
         if self._seq is None or self._seq.is_empty:
             return True
         return False

tests/core_test.py

@@ -537,6 +537,11 @@ def test_reduce():
     assert 46 == core.reduce(core.__PLUS__, 45, [1])
 
 
+def test_reduce_with_lazy_seq():
+    assert 25 == core.reduce(core.__PLUS__, core.filter_(core.odd__Q__, vec.v(1, 2, 3, 4, 5, 6, 7, 8, 9)))
+    assert 25 == core.reduce(core.__PLUS__, 0, core.filter_(core.odd__Q__, vec.v(1, 2, 3, 4, 5, 6, 7, 8, 9)))
+
+
 def test_comp():
     assert 1 == core.comp()(1)
     assert "hi" == core.comp()("hi")

tests/seq_test.py

@@ -15,21 +15,21 @@ def test_to_sequence():
 
 def test_lazy_sequence():
     s = lseq.LazySeq(lambda: None)
-    assert not s.is_empty, "LazySeq has not been realized yet"
+    assert s.is_empty
     assert None is s.first
     assert lseq.EMPTY is s.rest
     assert s.is_realized
     assert s.is_empty, "LazySeq has been realized and is empty"
 
     s = lseq.LazySeq(lambda: lseq.EMPTY)
-    assert not s.is_empty, "LazySeq has not been realized yet"
+    assert s.is_empty
     assert None is s.first
     assert lseq.EMPTY is s.rest
     assert s.is_realized
     assert s.is_empty, "LazySeq has been realized and is empty"
 
     s = lseq.LazySeq(lambda: lseq.sequence([1]))
-    assert not s.is_empty, "LazySeq has not been realized yet"
+    assert not s.is_empty
     assert 1 == s.first
     assert lseq.EMPTY is s.rest
     assert s.is_realized
@@ -45,21 +45,21 @@ def inner_inner_seq():
         return lseq.LazySeq(inner_seq).cons(1)
 
     s = lseq.LazySeq(lazy_seq)
-    assert not s.is_empty, "LazySeq has not been realized yet"
+    assert not s.is_empty
     assert 1 == s.first
     assert isinstance(s.rest, lseq.LazySeq)
     assert s.is_realized
     assert not s.is_empty, "LazySeq has been realized and is not empty"
 
     r = s.rest
-    assert not r.is_empty, "LazySeq has not been realized yet"
+    assert not r.is_empty
     assert 2 == r.first
     assert isinstance(r.rest, lseq.LazySeq)
     assert r.is_realized
     assert not r.is_empty, "LazySeq has been realized and is not empty"
 
     t = r.rest
-    assert not t.is_empty, "LazySeq has not been realized yet"
+    assert not t.is_empty
     assert 3 == t.first
     assert lseq.EMPTY is t.rest
     assert t.is_realized