From 361e2a3c1c7d51d12c9eab86bb4a72bd2ef080bf Mon Sep 17 00:00:00 2001
From: Nat Quayle Nelson <natquaylenelson@gmail.com>
Date: Wed, 25 Nov 2020 13:59:28 -0700
Subject: [PATCH] lambda

---
 src/kiss/Reader.hx                | 3 +++
 src/kiss/SpecialForms.hx          | 4 +++-
 src/test/cases/BasicTestCase.hx   | 4 ++++
 src/test/cases/BasicTestCase.kiss | 6 +++++-
 4 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/kiss/Reader.hx b/src/kiss/Reader.hx
index e14fbb73..7c828dba 100644
--- a/src/kiss/Reader.hx
+++ b/src/kiss/Reader.hx
@@ -50,6 +50,9 @@ class Reader {
 
         readTable["!"] = (stream:Stream) -> CallExp(Symbol("not").withPos(stream.position()), [assertRead(stream, readTable)]);
 
+        // Helpful for defining predicates to pass to Haxe functions:
+        readTable["?"] = (stream:Stream) -> CallExp(Symbol("Prelude.truthy").withPos(stream.position()), [assertRead(stream, readTable)]);
+
         // Because macro keys are sorted by length and peekChars(0) returns "", this will be used as the default reader macro:
         readTable[""] = (stream) -> Symbol(nextToken(stream, "a symbol name"));
 
diff --git a/src/kiss/SpecialForms.hx b/src/kiss/SpecialForms.hx
index ecf226db..bcc62d9b 100644
--- a/src/kiss/SpecialForms.hx
+++ b/src/kiss/SpecialForms.hx
@@ -110,7 +110,9 @@ class SpecialForms {
             EBlock([EVars(varDefs).withContextPos(), EBlock(body.map(convert)).withContextPos()]).withContextPos();
         };
 
-        // TODO special form for lambda
+        map["lambda"] = (args:Array<ReaderExp>, convert:ExprConversion) -> {
+            EFunction(FArrow, Helpers.makeFunction(null, args[0], args.slice(1), convert)).withContextPos();
+        };
 
         // TODO special form for for loop
         // TODO special form for list comprehension
diff --git a/src/test/cases/BasicTestCase.hx b/src/test/cases/BasicTestCase.hx
index 2d260ed1..3824e408 100644
--- a/src/test/cases/BasicTestCase.hx
+++ b/src/test/cases/BasicTestCase.hx
@@ -184,4 +184,8 @@ class BasicTestCase extends Test {
         Assert.equals(false, BasicTestCase.myNot1);
         Assert.equals(false, BasicTestCase.myNot2);
     }
+
+    function testLambda() {
+        Assert.equals([5, 6].toString(), BasicTestCase.myFilteredList.toString());
+    }
 }
diff --git a/src/test/cases/BasicTestCase.kiss b/src/test/cases/BasicTestCase.kiss
index 4794c3f1..310adfb4 100644
--- a/src/test/cases/BasicTestCase.kiss
+++ b/src/test/cases/BasicTestCase.kiss
@@ -140,4 +140,8 @@
     loc)
 
 (defvar myNot1 (not 5))
-(defvar myNot2 !5)
\ No newline at end of file
+(defvar myNot2 !5)
+
+(defvar myFilteredList (begin 
+    (deflocal l [-1 -2 5 -3 6])
+    (l.filter (lambda [v] (< 0 v)))))
\ No newline at end of file