test circular imports

Author: xieyuheng

TODO.md

@@ -1,5 +1,3 @@
-test circular imports
-
 # lazy evaluation
 
 [problem] we can use `Y`! -- `DelayedApply` can replace `Lazy`? -- what evaluation strategy is this?

examples/nat-even-odd-imported.lisp

@@ -0,0 +1,37 @@
+(import true false if and or not "bool.lisp")
+(import zero add1 sub1 zero? "nat-church.lisp")
+(import one two three four "nat-church.lisp")
+
+(import even? "nat-even.lisp")
+(import odd? "nat-odd.lisp")
+
+(assert-equal true (even? zero))
+(assert-equal true (even? two))
+(assert-equal true (even? four))
+
+(assert-equal false (even? one))
+(assert-equal false (even? three))
+
+(assert-equal false (odd? zero))
+(assert-equal false (odd? two))
+(assert-equal false (odd? four))
+
+(assert-equal true (odd? one))
+(assert-equal true (odd? three))
+
+;; test equivalence between recursive functions
+
+(assert-equal even? even?)
+(assert-equal odd? odd?)
+
+(assert-equal
+  even?
+  (lambda (n)
+    (if (zero? n) true
+        (odd? (sub1 n)))))
+
+(assert-not-equal
+  odd?
+  (lambda (n)
+    (if (zero? n) true
+        (odd? (sub1 n)))))

examples/nat-even.lisp

@@ -0,0 +1,8 @@
+(import true false if and or not "bool.lisp")
+(import zero add1 sub1 zero? "nat-church.lisp")
+(import one two three four "nat-church.lisp")
+(import odd? "nat-odd.lisp")
+
+(define (even? n)
+  (if (zero? n) true
+      (odd? (sub1 n))))

examples/nat-odd.lisp

@@ -0,0 +1,8 @@
+(import true false if and or not "bool.lisp")
+(import zero add1 sub1 zero? "nat-church.lisp")
+(import one two three four "nat-church.lisp")
+(import even? "nat-even.lisp")
+
+(define (odd? n)
+  (if (zero? n) false
+      (even? (sub1 n))))

src/lang/evaluate/evaluateWithDelay.ts

@@ -16,7 +16,9 @@ export function evaluateWithDelay(mod: Mod, env: Env, exp: Exp): Value {
       value = modFindValue(mod, exp.name)
       if (value !== undefined) return value
 
-      throw new Error(`Unknown name: ${exp.name}`)
+      throw new Error(
+        `[evaluateWithDelay] I meet undefined name: ${exp.name}, in mod: ${mod.url}`,
+      )
     }
 
     case "Lambda": {