From e5d22ae6ad42db3e0cfcd9ea96033e8b5ac2db87 Mon Sep 17 00:00:00 2001
From: Nat Quayle Nelson <natquaylenelson@gmail.com>
Date: Sat, 25 Feb 2023 16:22:05 -0700
Subject: [PATCH] Make pattern matching in macros a compiler error. close #173

---
 kiss/src/kiss/Helpers.hx               | 13 ++++++++++
 kiss/src/kiss/SpecialForms.hx          |  4 +++
 kiss/src/test/cases/BasicTestCase.hx   |  4 +++
 kiss/src/test/cases/BasicTestCase.kiss | 35 ++++++++++++++++++++++++++
 4 files changed, 56 insertions(+)

diff --git a/kiss/src/kiss/Helpers.hx b/kiss/src/kiss/Helpers.hx
index 554f83f4..77d7eec9 100644
--- a/kiss/src/kiss/Helpers.hx
+++ b/kiss/src/kiss/Helpers.hx
@@ -257,6 +257,19 @@ class Helpers {
         var varsInScope:Array<Var> = [];
         function makeSwitchPattern(patternExp:ReaderExp):Array<Expr> {
             return switch (patternExp.def) {
+                case _ if (k.hscript):
+                    trace(patternExp);
+                    var patternExpr = k.forCaseParsing().convert(patternExp);
+                    [switch (patternExpr.expr) {
+                        case EConst(CString(_, _)):
+                            patternExpr;
+                        case EConst(CInt(_) | CFloat(_)):
+                            patternExpr;
+                        case EConst(CIdent("null")):
+                            patternExpr;
+                        default:
+                            throw KissError.fromExp(caseExp, "case expressions in macros can only match literal values");
+                    }];
                 case CallExp({pos: _, def: Symbol("when")}, whenExps):
                     patternExp.checkNumArgs(2, 2, "(when <guard> <pattern>)");
                     if (guard != null)
diff --git a/kiss/src/kiss/SpecialForms.hx b/kiss/src/kiss/SpecialForms.hx
index 7c0977ca..cf8138af 100644
--- a/kiss/src/kiss/SpecialForms.hx
+++ b/kiss/src/kiss/SpecialForms.hx
@@ -371,6 +371,10 @@ class SpecialForms {
                     false;
             }
 
+            if (k.hscript && isTupleCase) {
+                throw KissError.fromExp(wholeExp, "tuple-matching is not supported in a macro");
+            }
+
             var b = wholeExp.expBuilder();
             var defaultExpr = switch (cases[-1].def) {
                 case CallExp({pos: _, def: Symbol("otherwise")}, otherwiseExps):
diff --git a/kiss/src/test/cases/BasicTestCase.hx b/kiss/src/test/cases/BasicTestCase.hx
index 26a7f269..d7e742e6 100644
--- a/kiss/src/test/cases/BasicTestCase.hx
+++ b/kiss/src/test/cases/BasicTestCase.hx
@@ -435,6 +435,10 @@ class BasicTestCase extends Test {
         _testLambdaTypeAnnotations();
     }
 
+    function testCaseMacroError() {
+        _testCaseMacroError();
+    }
+
     var aNullToPrint = null;
 }
 
diff --git a/kiss/src/test/cases/BasicTestCase.kiss b/kiss/src/test/cases/BasicTestCase.kiss
index b5e46f6d..bfa4d889 100644
--- a/kiss/src/test/cases/BasicTestCase.kiss
+++ b/kiss/src/test/cases/BasicTestCase.kiss
@@ -742,6 +742,41 @@ From:[(assert false (+ \"false \" \"should \" \"have \" \"been \" \"true\"))]" m
     (Assert.isTrue (lambdaTest 5 6))
     (lambdaTest2))
 
+(defMacro __testCaseMacroError1 []
+    (case ["thing" 2] `5))
+
+(defMacro __testCaseMacroError2 []
+    (case 5
+        ((Some v) `false)
+        (otherwise `false)))
+
+(defMacro __testCaseMacroError3 []
+    (case 5
+        ([not this] `false)
+        (otherwise `false)))
+
+(defMacro __testCaseMacroError4 [s]
+    (case (symbolNameValue s)
+        ("rightSymbol" `true)
+        (otherwise `false)))
+
+(defMacro __testCaseMacroError5 [n]
+    (case (eval n)
+        (5 `true)
+        (otherwise `false)))
+
+(function _testCaseMacroError []
+    (assertThrowsAtCompileTime
+        (__testCaseMacroError1))
+    (assertThrowsAtCompileTime
+        (__testCaseMacroError2))
+    (assertThrowsAtCompileTime
+        (__testCaseMacroError3))
+    (Assert.isTrue (__testCaseMacroError4 rightSymbol))
+    (Assert.isFalse (__testCaseMacroError4 wrongSymbol))
+    (Assert.isTrue (__testCaseMacroError5 5))
+    (Assert.isFalse (__testCaseMacroError5 6)))
+
 (function _testHaxeProperties []
     (Assert.equals 5 staticProp)
     (Assert.equals 9 (set staticProp 9))