improved scanning for return statement in routines that should return a value.

compiler/res/prog8lib/string.p8

@@ -178,7 +178,7 @@ _found		sty  P8ZP_SCRATCH_B1
 
     asmsub compare(uword string1 @R0, uword string2 @AY) clobbers(Y) -> byte @A {
         ; Compares two strings for sorting.
-        ; Returns -1 (255), 0 or 1 depeding on wether string1 sorts before, equal or after string2.
+        ; Returns -1 (255), 0 or 1 depending on wether string1 sorts before, equal or after string2.
         ; Note that you can also directly compare strings and string values with eachother using
         ; comparison operators ==, < etcetera (it will use strcmp for you under water automatically).
         %asm {{

compiler/src/prog8/compiler/astprocessing/AstChecker.kt

@@ -196,6 +196,28 @@ internal class AstChecker(private val program: Program,
         super.visit(label)
     }
 
+    private fun hasReturnOrJump(scope: INameScope): Boolean {
+        class Searcher: IAstVisitor
+        {
+            var count=0
+
+            override fun visit(returnStmt: Return) {
+                count++
+            }
+            override fun visit(jump: Jump) {
+                count++
+            }
+        }
+
+        val s=Searcher()
+        for(stmt in scope.statements) {
+            stmt.accept(s)
+            if(s.count>0)
+                return true
+        }
+        return s.count > 0
+    }
+
     override fun visit(subroutine: Subroutine) {
         fun err(msg: String) = errors.err(msg, subroutine.position)
 
@@ -218,7 +240,7 @@ internal class AstChecker(private val program: Program,
 
         // subroutine must contain at least one 'return' or 'goto'
         // (or if it has an asm block, that must contain a 'rts' or 'jmp' or 'bra')
-        if(subroutine.statements.count { it is Return || it is Jump } == 0) {
+        if(!hasReturnOrJump(subroutine)) {
             if (subroutine.amountOfRtsInAsm() == 0) {
                 if (subroutine.returntypes.isNotEmpty()) {
                     // for asm subroutines with an address, no statement check is possible.

examples/test.p8

@@ -7,16 +7,22 @@
 main {
 
     sub start() {
-        ubyte xx=existing_entry(1,2)
+        ubyte num_entries
+
+        num_entries = 10
+        ubyte ix
+        for ix in (num_entries-1)*2 downto 0 step -2 {
+            txt.print_ub(ix)
+            txt.spc()
         }
 
-    ; TODO FIX COMPILER ERROR ABOUT MISSING RETURN
-
-    sub existing_entry(ubyte hash, uword symbol) -> ubyte {
-        if hash>10
-            return 44
-        else
-            return false
+        txt.nl()
+        num_entries = 10
+        for ix in num_entries-1 downto 0 {
+            txt.print_ub(ix*2)
+            txt.spc()
         }
+    }
+
 }