From b8693af68bb70ad41da2cb2ba3042d7b3325f7d9 Mon Sep 17 00:00:00 2001
From: Sasha Koshka <sashakoshka@tebibyte.media>
Date: Thu, 13 Oct 2022 02:20:47 -0400
Subject: [PATCH] Added some permission checks

---
 analyzer/analyzer.go                          | 13 ++++++++
 analyzer/type-section.go                      | 30 +++++++++++++++++++
 tests/analyzer/typeSection/main.arf           |  8 +++--
 tests/analyzer/typeSection/something/main.arf |  5 +++-
 4 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/analyzer/analyzer.go b/analyzer/analyzer.go
index 1f9ecd8..1718463 100644
--- a/analyzer/analyzer.go
+++ b/analyzer/analyzer.go
@@ -249,6 +249,19 @@ func (analyzer *analysisOperation) typeCheck (
 	return
 }
 
+// inCurrentModule returns whether or not the specified section resides within
+// the current module.
+func (analyzer *analysisOperation) inCurrentModule (
+	section Section,
+) (
+	inCurrent bool,
+){
+	inCurrent =
+		section.locator().modulePath ==
+		analyzer.currentPosition.modulePath
+	return
+}
+
 // doIndent perfroms a fmt.Sprint operation on input, indenting the string. This
 // does not add a trailing newline.
 func doIndent (indent int, input ...any) (output string) {
diff --git a/analyzer/type-section.go b/analyzer/type-section.go
index 4825250..3a408cc 100644
--- a/analyzer/type-section.go
+++ b/analyzer/type-section.go
@@ -169,6 +169,8 @@ func (analyzer *analysisOperation) analyzeObjectMembers (
 	err error,
 ) {
 	inheritedSection := into.what.actual
+	inheritsFromSameModule := analyzer.inCurrentModule(inheritedSection)
+	
 	for index := 0; index < from.MembersLength(); index ++ {
 		inputMember := from.Member(index)
 
@@ -185,6 +187,20 @@ func (analyzer *analysisOperation) analyzeObjectMembers (
 			// modifying default value/permissions of an
 			// inherited member
 
+			canAccessMember := 
+				inheritsFromSameModule ||
+				inheritedMember.permission !=
+				types.PermissionPrivate
+
+			if !canAccessMember {
+				err = inputMember.NewError (
+					"inherited member is private (pv) in " +
+					"parent type, and cannot be modified " +
+					"here",
+					infoerr.ErrorKindError)
+				return
+			}
+
 			outputMember.what = inheritedMember.what
 			if !inputMember.Type().Nil() {
 				err = inputMember.NewError (
@@ -202,11 +218,25 @@ func (analyzer *analysisOperation) analyzeObjectMembers (
 				return
 			}
 
+			canOverwriteMember :=
+				inheritsFromSameModule ||
+				inheritedMember.permission ==
+				types.PermissionReadWrite
+
 			// apply default value
 			if inputMember.Argument().Nil() {
 				// if it is unspecified, inherit it
 				outputMember.argument = inheritedMember.argument
 			} else {
+				if !canOverwriteMember {
+					err = inputMember.Argument().NewError (
+						"member is read-only (ro) in " +
+						"parent type, its default " +
+						"value cannot be overridden",
+						infoerr.ErrorKindError)
+					return
+				}
+				
 				outputMember.argument,
 				err = analyzer.analyzeArgument(inputMember.Argument())
 				if err != nil { return }
diff --git a/tests/analyzer/typeSection/main.arf b/tests/analyzer/typeSection/main.arf
index 7714a49..8255521 100644
--- a/tests/analyzer/typeSection/main.arf
+++ b/tests/analyzer/typeSection/main.arf
@@ -10,7 +10,11 @@ type ro cBasicObject:Obj
 	ro that:UInt
 	ro this:Int
 
-type ro dInheritedFromOther:something.Thing
+type ro dInheritFromOther:something.aBasic
 
 type ro eInheritObject:cBasicObject
-	rw that
+	ro that 5
+
+type ro dInheritObjectFromOther:something.bBird
+	ro wing 2
+	ro beak:Int 238
diff --git a/tests/analyzer/typeSection/something/main.arf b/tests/analyzer/typeSection/something/main.arf
index 7440373..e9aed4c 100644
--- a/tests/analyzer/typeSection/something/main.arf
+++ b/tests/analyzer/typeSection/something/main.arf
@@ -1,3 +1,6 @@
 :arf
 ---
-type ro Thing:Int
+type ro aBasic:Int
+
+type ro bBird:Obj
+	rw wing:Int 2