identity function, repl upgrade

2 files changed, 71 insertions, 7 deletions

diff --git a/src/interpreter/builtins.ts b/src/interpreter/builtins.ts
index bc666e9..16322f1 100644
--- a/src/interpreter/builtins.ts
+++ b/src/interpreter/builtins.ts
@@ -202,6 +202,51 @@ const addBinaryArithmeticOperationsTo = (env: Environment) => {
   return env;
 };
 
+const addIdentityFunctionTo = (env: Environment) => {
+  env.set('id', {
+    type: 'function',
+    value: {
+      signatures: [
+        {
+          arguments: ['null'],
+          return: 'null',
+        },
+        {
+          arguments: ['int'],
+          return: 'int',
+        },
+        {
+          arguments: ['real'],
+          return: 'real',
+        },
+        {
+          arguments: ['bool'],
+          return: 'bool',
+        },
+        {
+          arguments: ['string'],
+          return: 'string',
+        },
+        {
+          arguments: ['bytearray'],
+          return: 'bytearray',
+        },
+        {
+          arguments: ['function'],
+          return: 'function',
+        },
+        {
+          arguments: ['reference'],
+          return: 'reference',
+        },
+      ],
+      body: ({ value }: Denotable) => value,
+    },
+  });
+
+  return env;
+};
+
 export const putBuiltinsOnEnvironemtn = (env: Environment) => {
   return [
     addBinaryArithmeticOperationsTo,
@@ -210,5 +255,6 @@ export const putBuiltinsOnEnvironemtn = (env: Environment) => {
     addNumberComparisonOperationsTo,
     addBooleanAlgebraOperationsTo,
     addEqualityOperationsTo,
+    addIdentityFunctionTo,
   ].reduce((acc, builtinsAdder) => builtinsAdder(acc), env);
 };
diff --git a/src/interpreter/interpreter.ts b/src/interpreter/interpreter.ts
index 94e263c..278e027 100644
--- a/src/interpreter/interpreter.ts
+++ b/src/interpreter/interpreter.ts
@@ -1,6 +1,7 @@
 import {
   type ContinuationExpression,
   type PrimitiveOperationExpression,
+  type ApplicationExpression,
   type Program,
   type Value,
 } from '@/parser';
@@ -16,7 +17,7 @@ import { putBuiltinsOnEnvironemtn } from './builtins';
 const evaluateValue = (
   value: Value,
   env: Environment,
-  logger: TracingLogger,
+  _logger: TracingLogger,
 ): Denotable => {
   if (typeof value === 'string') {
     return { type: 'string', value };
@@ -35,6 +36,18 @@ const evaluateValue = (
   throw new InvalidStateError(`Invalid value: ${value}`);
 };
 
+const evaluateApplicationExpression = (
+  { application }: ApplicationExpression,
+  env: Environment,
+  logger: TracingLogger,
+): Denotable => {
+  const { fn, args } = application;
+  const argValues = args.map(arg =>
+    evaluateValue(arg, env, logger.createChild('evaluateValue')),
+  );
+  return env.apply(fn.name, argValues);
+};
+
 const evaluatePrimitiveOperation = (
   { primitiveOperation }: PrimitiveOperationExpression,
   env: Environment,
@@ -61,6 +74,7 @@ const evaluatePrimitiveOperation = (
       logger.warn(
         `Expected 2 continuations for boolean result, got ContinuationLength=(${continuations.length})`,
       );
+      return result;
     }
 
     const [trueContinuation, falseContinuation] = continuations;
@@ -79,7 +93,7 @@ const evaluatePrimitiveOperation = (
     );
   } else if (continuations.length === 0) {
     logger.warn(
-      `!! Expected 1 continuation in continuation list... implicitly returning result but PLEASE NOTE this is technically undefined behavior !!`,
+      "Expected 1 continuation for non-boolean result, but there wasn't any. Implicitly returning the result", // technically undefined behavior
     );
     return result;
   }
@@ -107,6 +121,15 @@ const evaluteContinuationExpression = (
     );
   }
 
+  if ('application' in expr) {
+    logger.debug('Evaluating function application');
+    return evaluateApplicationExpression(
+      expr,
+      env,
+      logger.createChild('evaluateApplicationExpression'),
+    );
+  }
+
   if ('record' in expr) {
     throw new NotImplementedError('Continuation records are not supported yet');
   }
@@ -116,11 +139,6 @@ const evaluteContinuationExpression = (
   if ('offset' in expr) {
     throw new NotImplementedError('Continuation offset is not supported yet');
   }
-  if ('application' in expr) {
-    throw new NotImplementedError(
-      'Continuation application is not supported yet',
-    );
-  }
   if ('switch' in expr) {
     throw new NotImplementedError('Continuation switch is not supported yet');
   }