Miscellaneous fixes

.gitignore

@@ -4,8 +4,6 @@
 build/
 .dart_tool/
 deploy/
-# Remove the following pattern if you wish to check in your lock file
-pubspec.lock
 
 # Directory created by dartdoc
 doc/api/

lib/src/core/logging.dart

@@ -50,7 +50,8 @@ class SchemeException extends Value implements Exception {
     if (!showTrace || callStack.isEmpty) return 'Error: $message';
     var str = 'Traceback (most recent call last)\n';
     for (int i = 0; i < callStack.length; i++) {
-      str += '$i\t${callStack[i]}\n';
+      var space = " " * (6 - i.toString().length);
+      str += '$i$space${callStack[i]}\n';
     }
     return str + 'Error: $message';
   }

lib/src/core/special_forms.dart

@@ -84,7 +84,7 @@ Undefined doSetForm(SchemeList<Expression> expressions, Frame env) {
   checkForm(expressions, 2, 2);
   Expression name = expressions.first;
   if (name is! SchemeSymbol) throw SchemeException("$name is not a symbol");
-  Expression value = schemeEval(expressions.skip(1).first, env);
+  Value value = schemeEval(expressions.skip(1).first, env);
   env.update(name as SchemeSymbol, value);
   return undefined;
 }

lib/src/core/values.dart

@@ -113,8 +113,7 @@ class Promise extends Value {
   /// Evaluates the promise, or returns the result if already evaluated.
   Expression force() {
     if (!_evaluated) {
-      expr = schemeEval(expr, env);
-      env.interpreter.language.validateCdr(expr,
+      expr = env.interpreter.language.validateCdr(schemeEval(expr, env),
           errorMessage: "A promise must contain a pair, stream, or nil");
       _evaluated = true;
     }

lib/src/web/js_interop.dart

@@ -1,19 +1,24 @@
+@JS()
 library cs61a_scheme.web.js_interop;
 
 import 'dart:async';
 import 'dart:js';
 
+import 'package:js/js.dart';
+
 import 'package:cs61a_scheme/cs61a_scheme_extra.dart';
 
 class JsProcedure extends Procedure {
   final SchemeSymbol name = null;
   final JsFunction fn;
   JsProcedure(this.fn);
-  Expression apply(SchemeList args, Frame env) {
+  Value apply(SchemeList args, Frame env) {
     var result = fn.apply(args.map((arg) => arg.toJS()).toList());
     return jsToScheme(result);
   }
 
+  toString() => "#[js-function]";
+
   toJS() => fn;
 }
 
@@ -42,19 +47,21 @@ class NativeValue extends Value {
 }
 
 Value jsToScheme(obj) {
-  if (obj is Expression) return obj;
+  if (obj is Value) return obj;
   if (obj is num) return Number.fromNum(obj);
   if (obj is bool) return obj ? schemeTrue : schemeFalse;
   if (obj is String) return SchemeString(obj);
-  if (obj is SchemeFunction) return obj.procedure;
-  if (obj is JsFunction) return JsProcedure(obj);
   if (obj is JsObject) return jsObjectToScheme(obj);
   if (obj == null) return undefined;
   if (obj == context['undefined']) return undefined;
-  return NativeValue(obj);
+  return unwrapSchemeProcedure(obj) ?? NativeValue(obj);
 }
 
 Value jsObjectToScheme(JsObject obj) {
+  if (obj.hasProperty('wrappedSchemeProcedure')) {
+    return obj['wrappedSchemeProcedure'];
+  }
+  if (obj is JsFunction) return JsProcedure(obj);
   var type =
       context['Object']['prototype']['toString'].callMethod('call', [obj]);
   if (type == '[object Promise]') {
@@ -66,7 +73,7 @@ Value jsObjectToScheme(JsObject obj) {
   return JsValue(obj);
 }
 
-Expression jsEval(String code) {
+Value jsEval(String code) {
   try {
     return jsToScheme(context.callMethod("eval", [code]));
     // ignore: avoid_catches_without_on_clauses
@@ -76,17 +83,18 @@ Expression jsEval(String code) {
   }
 }
 
-class SchemeFunction {
-  Procedure procedure;
-  Frame env;
-  SchemeFunction(this.procedure, this.env);
-  call() => schemeApply(procedure, SchemeList(nil), null).toJS();
-  noSuchMethod(Invocation invocation) {
-    if (invocation.memberName == const Symbol("call")) {
-      var args = invocation.positionalArguments.map(jsToScheme);
-      return schemeApply(procedure, SchemeList.fromIterable(args), env).toJS();
-    }
-    throw SchemeException(
-        "Something has gone horribly wrong with wrapped procedures");
-  }
-}
+@JS("wrapSchemeProcedure")
+external JsFunction wrapSchemeProcedure(dynamic fn(args), procedure);
+
+@JS("unwrapSchemeProcedure")
+external Procedure unwrapSchemeProcedure(obj);
+
+JsFunction procedureToJsFunction(Procedure procedure, Frame env) =>
+    wrapSchemeProcedure(allowInterop((args) {
+      var schemeArgs = <Value>[];
+      for (var arg in args) {
+        schemeArgs.add(jsToScheme(arg));
+      }
+      return schemeApply(procedure, SchemeList.fromIterable(schemeArgs), env)
+          .toJS();
+    }), procedure);

lib/src/web/web_library.dart

@@ -35,7 +35,8 @@ class WebLibrary extends SchemeLibrary with _$WebLibraryMixin {
 
   void importAll(Frame env) {
     super.importAll(env);
-    Procedure.jsProcedure = (procedure) => SchemeFunction(procedure, env);
+    Procedure.jsProcedure =
+        (procedure) => procedureToJsFunction(procedure, env);
   }
 
   /// Evaluates a piece of JavaScript code and returns the result.