updated lis.py examples

02-array-seq/lispy/py3.10/meta_test.py

@@ -0,0 +1,64 @@
+import operator as op
+
+from lis import run
+
+env_scm = """
+(define standard-env (list
+    (list (quote +) +)
+    (list (quote -) -)
+))
+standard-env
+"""
+
+def test_env_build():
+    got = run(env_scm)
+    assert got == [['+', op.add], ['-', op.sub]]
+
+scan_scm = """
+(define l (quote (a b c)))
+(define (scan what where)
+    (if (null? where)
+        ()
+        (if (eq? what (car where))
+            what
+            (scan what (cdr where))))
+)
+"""
+
+def test_scan():
+    source = scan_scm + '(scan (quote a) l )'
+    got = run(source)
+    assert got == 'a'
+
+
+def test_scan_not_found():
+    source = scan_scm + '(scan (quote z) l )'
+    got = run(source)
+    assert got == []
+
+
+lookup_scm = """
+(define env (list
+    (list (quote +) +)
+    (list (quote -) -)
+))
+(define (lookup what where)
+    (if (null? where)
+        ()
+        (if (eq? what (car (car where)))
+            (car (cdr (car where)))
+            (lookup what (cdr where))))
+)
+"""
+
+def test_lookup():
+    source = lookup_scm + '(lookup (quote +) env)'
+    got = run(source)
+    assert got == op.add
+
+
+def test_lookup_not_found():
+    source = lookup_scm + '(lookup (quote z) env )'
+    got = run(source)
+    assert got == []
+