formatValue

Author: xieyuheng

TODO.md

@@ -1,3 +1,7 @@
+# readback
+
+remove `readback`
+
 # lazy evaluation
 
 we still can bring back lazy evaluation by lazy + box,
@@ -34,7 +38,3 @@ why top level wrap need a eta?
 ```
 
 can adding lazy evaluation help fix this?
-
-# readback
-
-be able to readback ackermann function -- maybe use occur check for all the sub-expressions

src/lang/format/formatValue.ts

@@ -0,0 +1,42 @@
+import { type Neutral, type Value } from "../value/index.ts"
+import { formatExp } from "./formatExp.ts"
+
+export function formatValue(value: Value): string {
+  switch (value.kind) {
+    case "NotYet": {
+      return formatNeutral(value.neutral)
+    }
+
+    case "Lambda": {
+      if (value.definedName === undefined) {
+        return `(lambda (${value.name}) ${value.ret})`
+      } else {
+        return value.definedName
+      }
+    }
+
+    case "Lazy": {
+      return formatExp(value.exp)
+    }
+
+    case "DelayedApply": {
+      const target = formatValue(value.target)
+      const arg = formatValue(value.arg)
+      return `(${target} ${arg})`
+    }
+  }
+}
+
+function formatNeutral(neutral: Neutral): string {
+  switch (neutral.kind) {
+    case "Var": {
+      return neutral.name
+    }
+
+    case "Apply": {
+      const target = formatNeutral(neutral.target)
+      const arg = formatValue(neutral.arg)
+      return `(${target} ${arg})`
+    }
+  }
+}

src/lang/format/index.ts

@@ -1 +1,2 @@
 export * from "./formatExp.ts"
+export * from "./formatValue.ts"