Omit *context* if it is not constrainted

liphe · Apr 2, 2020 · e4d3385 · e4d3385
1 parent 2e27463
commit e4d3385
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Showing 2 changed files with 43 additions and 13 deletions.
diff --git a/packages/delisp-core/src/type-utils.ts b/packages/delisp-core/src/type-utils.ts
@@ -1,7 +1,7 @@
 import { InvariantViolation } from "./invariant";
 import { generateUniqueTVar } from "./type-generate";
 import * as T from "./types";
-import { flatMap, flatten, last, unique } from "./utils";
+import { flatten, flatMap, last, unique } from "./utils";
 
 export function isTVar(t: T.Type): t is T.Var {
   return t.node.tag === "type-variable";
@@ -26,16 +26,24 @@ export function isFunctionType(t: T.Type): t is T.Application {
   return isConstantApplicationType(t, "->");
 }
 
-export function typeChildren<A>(type: T.TypeF<A[]>): A[] {
+export function countTypeOccurrences(variable: T.Var, type: T.Type): number {
+  return foldType(type, (t) => {
+    return t.node.tag === "type-variable" && t.node.name === variable.node.name
+      ? 1
+      : typeChildren(t).reduce((x, y) => x + y, 0);
+  });
+}
+
+export function typeChildren<A>(type: T.TypeF<A>): A[] {
   switch (type.node.tag) {
     case "constant":
     case "type-variable":
     case "empty-row":
       return [];
     case "application":
-      return flatten([type.node.op, ...type.node.args]);
+      return [type.node.op, ...type.node.args];
     case "row-extension":
-      return [...type.node.labelType, ...type.node.extends];
+      return [type.node.labelType, type.node.extends];
   }
 }
 
@@ -113,7 +121,7 @@ export function listTypeConstants(type: T.Type): T.Constant[] {
             },
           },
         ]
-      : typeChildren(t);
+      : flatten(typeChildren(t));
   });
 }
 
@@ -122,7 +130,7 @@ export function listTypeVariables(type: T.Type): string[] {
   return foldType(type, (t) => {
     return t.node.tag === "type-variable"
       ? [t.node.name]
-      : unique(typeChildren(t));
+      : unique(flatten(typeChildren(t)));
   });
 }
 

diff --git a/packages/liphe/pages/index.tsx b/packages/liphe/pages/index.tsx
@@ -154,16 +154,30 @@ export const FunctionExplorer: React.FC<{ fn: Delisp.SFunction<Typed> }> = ({
   }
   const type = Delisp.decomposeFunctionType(selfType);
 
+  const [, ...args] = fn.node.lambdaList.positionalArguments;
+  const [contextType, ...argsTypes] = type.args;
+
+  const isUnconstraintContext =
+    Delisp.isTVar(contextType) &&
+    Delisp.countTypeOccurrences(contextType, selfType) === 1;
+
   return (
     <div className={styles.function}>
       <span className={styles.functionLabel}>λ</span>
 
+      {isUnconstraintContext ? null : (
+        <div>
+          <strong>*context*</strong> -
+          <TypeExplorer type={contextType} />
+        </div>
+      )}
+
       <ul className={styles.functionArguments}>
-        {fn.node.lambdaList.positionalArguments.map((arg, argPosition) => {
+        {args.map((arg, argPosition) => {
           return (
             <li key={arg.name}>
               <IdentifierExplorer identifier={arg} /> -
-              <TypeExplorer type={type.args[argPosition]} />
+              <TypeExplorer type={argsTypes[argPosition]} />
             </li>
           );
         })}
@@ -206,17 +220,25 @@ export const IdentifierExplorer: React.FC<{
 };
 
 export default function Homepage() {
-  const module = Delisp.macroexpandModule(
-    Delisp.readModule(`
-(lambda (x1 x2) {:x (+ x1 x2) :y 20 :z {:name "david"} :callback (lambda () 3)})
-`)
-  );
+  const [code, setCode] = useState(`
+(lambda (x) 
+  (+ *context* x)
+  )`);
+
+  const module = Delisp.macroexpandModule(Delisp.readModule(code));
 
   const { typedModule } = Delisp.inferModule(module);
 
   return (
     <div>
       <PageLayout>
+        <textarea
+          value={code}
+          onChange={(event) => {
+            setCode(event.target.value);
+          }}
+        />
+
         <ModuleExplorer module={typedModule} />
       </PageLayout>
     </div>