letrec tests

tests/succeed/letrec/factorial.fathom

@@ -0,0 +1,14 @@
+// FIXME: using (x - 1) causes a crash in distillation (see https://github.com/yeslogic/fathom/issues/485)
+
+letrec
+    factorial : U32 -> U32
+    = fun (x : U32) => match x {
+        0 => 1,
+        _ => x * factorial (u32_sub x 1),
+    },
+    factorial_iter : U32 -> U32 -> U32
+    = fun (acc: U32) (x : U32) => match x {
+        0 => acc,
+        _ => factorial_iter (acc * x) (u32_sub x 1),
+    };
+(factorial, factorial_iter)

tests/succeed/letrec/factorial.snap

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+stdout = '''
+letrec 
+    factorial : U32 -> U32 = fun x => match x {
+        0 => 1,
+        _ => x * factorial (x - (1 : U32)),
+    },
+    factorial_iter : U32 -> U32 -> U32 = fun acc x => match x {
+        0 => acc,
+        _ => factorial_iter (acc * x) (x - (1 : U32)),
+    },
+;
+(factorial, factorial_iter) : (U32 -> U32, U32 -> U32 -> U32)
+'''
+stderr = ''

tests/succeed/letrec/fibonacci.fathom

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+// FIXME: using (x - 1) or (x - 2) causes a crash in distillation (see https://github.com/yeslogic/fathom/issues/485)
+
+letrec
+    fibonacci : U32 -> U32
+    = fun (x : U32) => match x {
+        0 => 0,
+        1 => 1,
+        _ => (fibonacci (u32_sub x 1)) + (fibonacci (u32_sub x 2)),
+    };
+fibonacci

tests/succeed/letrec/fibonacci.snap

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+stdout = '''
+letrec 
+    fibonacci : U32 -> U32 = fun x => match x {
+        0 => 0,
+        1 => 1,
+        _ => fibonacci (x - (1 : U32)) + fibonacci (x - (2 : U32)),
+    },
+;
+fibonacci : U32 -> U32
+'''
+stderr = ''

tests/succeed/letrec/parity.fathom

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+// FIXME: using (x - 1) causes a crash in distillation (see https://github.com/yeslogic/fathom/issues/485)
+
+letrec
+    is_even : U32 -> Bool
+    = fun (x : U32) => match x {
+        0 => true,
+        _ => is_odd (u32_sub x 1),
+    },
+
+    is_odd : U32 -> Bool
+    = fun (x : U32) => match x {
+        0 => false,
+        _ => is_even (u32_sub x 1),
+    },
+;
+(is_even, is_odd)

tests/succeed/letrec/parity.snap

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+stdout = '''
+letrec 
+    is_even : U32 -> Bool = fun x => match x {
+        0 => true,
+        _ => is_odd (x - (1 : U32)),
+    },
+    is_odd : U32 -> Bool = fun x => match x {
+        0 => false,
+        _ => is_even (x - (1 : U32)),
+    },
+;
+(is_even, is_odd) : (U32 -> Bool, U32 -> Bool)
+'''
+stderr = ''