From 4f2bdf0f7f76041c5f6acb6d5cb36d3249a804a5 Mon Sep 17 00:00:00 2001
From: Nat Quayle Nelson <natquaylenelson@gmail.com>
Date: Tue, 11 Nov 2025 18:58:11 -0600
Subject: [PATCH] KissInterp2 lambda/localFunction/function

---
 src/kiss/KissInterp2.kiss               | 60 ++++++++++++++++++++++++-
 src/test/cases/KissInterp2TestCase.hx   |  4 ++
 src/test/cases/KissInterp2TestCase.kiss |  4 ++
 3 files changed, 67 insertions(+), 1 deletion(-)

diff --git a/src/kiss/KissInterp2.kiss b/src/kiss/KissInterp2.kiss
index 64d3240..1008a50 100644
--- a/src/kiss/KissInterp2.kiss
+++ b/src/kiss/KissInterp2.kiss
@@ -16,7 +16,7 @@
 (prop &mut :Map<String,ReaderExpDef> callAliases (new Map))
 
 (prop :Map<String,Dynamic> globals [=>"false" false =>"true" true =>"null" null])
-(prop :kiss.List<Map<String,Dynamic>> localScopes [])
+(prop &mut :kiss.List<Map<String,Dynamic>> localScopes [])
 
 (prop :Map<String,(Array<ReaderExp>,Dynamic->Void)->Void> specialForms)
 
@@ -28,6 +28,47 @@
 		(let [name (symbolNameValue (first args))]
 			(evalCC (second args) ->val {(dictSet scope name val) (cc val)})))
 
+(method makeFunction [:Array<ReaderExp> argExps :Array<ReaderExp> bodyExps]
+	(let [capture (localScopes.copy)
+			argNames []
+			&mut hasOpt false
+			&mut minArgs 0]
+		(doFor arg argExps
+			(case arg.def
+			 	((MetaExp "rest" arg)
+					(throw "KissInterp2 does not support &rest args"))
+				((MetaExp "opt" arg)
+					(set hasOpt true)
+					(argNames.push (symbolNameValue arg)))
+				((Symbol argName)
+					(argNames.push argName)
+					(unless hasOpt
+						++minArgs))
+				(never otherwise)))
+		(let [f_ (lambda [:Array<Dynamic> args]
+					(let [currentLocals (localScopes.copy)
+							innerCapture (capture.copy)
+							// Oof -- everything needs to be synchronous
+							&mut :Dynamic returnValue null]
+						(set localScopes innerCapture)
+						(localScopes.push (new Map))
+						(doFor [idx argName] (enumerate argNames)
+							(dictSet (last localScopes) argName
+								(if (< idx argNames.length)
+										(nth args idx)
+									(if hasOpt
+											null
+										(throw "not enough arguments! need $argName")))))
+						(evalCC (ReaderExpDef.CallExp (object pos null def (ReaderExpDef.Symbol "begin")) bodyExps)
+							->v
+								{
+									(set localScopes currentLocals)
+									(set returnValue v)
+								})
+						returnValue))
+				f (Reflect.makeVarArgs f_)]
+			f)))
+
 (method :Map<String,(Array<ReaderExp>,Dynamic->Void)->Void> _specialForms [] [
 	=>"if"
 		->[args cc]
@@ -36,6 +77,7 @@
 					(if val
 							(evalCC (second args) cc)
 						(evalCC (third args) cc)))
+	// TODO handle early return
 	=>"begin"
 		->[args cc]
 			(_evalAllCC args ->values
@@ -87,6 +129,22 @@
 					(evalCC (second args)
 						->key
 							(cc (container.get key))))
+	=>"lambda"
+		->[args cc]
+			(let [argExps (Prelude.argList (first args) "lambda") bodyExps (rest args)]
+				(cc (makeFunction argExps bodyExps)))
+	=>"localFunction"
+		->[args cc]
+			(let [name (symbolNameValue (first args)) argExps (Prelude.argList (second args) "lambda") bodyExps (args.slice 2)
+					func (makeFunction argExps bodyExps)]
+				(dictSet (last localScopes) name func)
+				(cc func))
+	=>"function"
+		->[args cc]
+			(let [name (symbolNameValue (first args)) argExps (Prelude.argList (second args) "lambda") bodyExps (args.slice 2)
+					func (makeFunction argExps bodyExps)]
+				(dictSet globals name func)
+				(cc func))
 ])
 
 (method :ReaderExp read [:Dynamic input]
diff --git a/src/test/cases/KissInterp2TestCase.hx b/src/test/cases/KissInterp2TestCase.hx
index afb2f13..7b51223 100644
--- a/src/test/cases/KissInterp2TestCase.hx
+++ b/src/test/cases/KissInterp2TestCase.hx
@@ -37,4 +37,8 @@ class KissInterp2TestCase extends Test {
     function testNth() {
         _testNth();
     }
+    function testLambda() {
+        _testLambda();
+    }
+    
 }
\ No newline at end of file
diff --git a/src/test/cases/KissInterp2TestCase.kiss b/src/test/cases/KissInterp2TestCase.kiss
index 77756fd..d58d28a 100644
--- a/src/test/cases/KissInterp2TestCase.kiss
+++ b/src/test/cases/KissInterp2TestCase.kiss
@@ -44,3 +44,7 @@
     (let [interp (new Interp)]
 		(assertEval 2 "(nth [1 2 3] 1)")
 		(assertEval 9 #"(dictGet [=>"a" 2 =>"b" 9 =>"c" 3] "b")"#)))
+
+(function _testLambda []
+    (let [interp (new Interp)]
+		(assertEval 6 "(let [add ->[a b] (+ a b)] (add 2 4))")))