Stmts.Compute -- use deepForce

TODO.md

@@ -1,7 +1,5 @@
 improve termination error report -- `span` to `Clause` first
 
-Stmts.Compute -- use `deepForce`
-
 support mutual recursion within `Mod`
 
 # later

src/lang/stmts/Compute.ts

@@ -12,6 +12,6 @@ export class Compute extends Stmt {
 
   async execute(mod: Mod): Promise<StmtOutput> {
     const value = evaluate(mod.env, this.exp)
-    return formatValue(Values.force(value))
+    return formatValue(Values.deepForce(value))
   }
 }

src/lang/value/deepForce.ts

@@ -0,0 +1,31 @@
+import * as Actions from "../actions"
+import { evaluate } from "../exp"
+import * as Values from "../value"
+import { Value } from "../value"
+
+export function deepForce(value: Value): Value {
+  value = Values.force(value)
+
+  switch (value.kind) {
+    case "Lazy": {
+      return deepForce(evaluate(value.env, value.exp))
+    }
+
+    case "FnMatch": {
+      const result = Actions.doApUnfolded(value, [])
+      return result.kind === "FnMatch" ? result : deepForce(result)
+    }
+
+    case "Ap": {
+      const unfolded = Values.unfoldAp(value)
+      const target = deepForce(unfolded.target)
+      if (target.kind === "Coctor") return value
+      const result = Actions.doAp(deepForce(value.target), deepForce(value.arg))
+      return result.kind === "Ap" ? result : deepForce(result)
+    }
+
+    default: {
+      return value
+    }
+  }
+}

src/lang/value/index.ts

@@ -1,4 +1,5 @@
 export * from "./Clause"
+export * from "./deepForce"
 export * from "./force"
 export * from "./formatClause"
 export * from "./formatValue"

std/datatypes/List.test.mu.out

@@ -1,4 +1,4 @@
 (null Nat)
 (cons Nat zero (null Nat))
 (cons Nat zero (cons Nat zero (null Nat)))
-(add1 (length A tail))
+(add1 (add1 zero))

std/datatypes/Nat.test.mu.out

@@ -5,6 +5,6 @@ zero
 zero
 zero
 (add1 zero)
-(add1 (add x y))
 (add1 zero)
-(add1 (add x y))
+(add1 zero)
+(add1 (add1 zero))