optimize @( &thing )) in ast into just thing

compiler/src/prog8/compiler/intermediate/IntermediateProgram.kt

@@ -69,7 +69,7 @@ class IntermediateProgram(val name: String, var loadAddress: Int, val heap: Heap
         optimizeMultipleSequentialLineInstrs()
         optimizeCallReturnIntoJump()
         optimizeConditionalBranches()
-        // todo: add more optimizations to stackvm code
+        // todo: add more optimizations to intermediate code! such as:  pop X + push X  ->  peek X  (might require new opcodes)
 
         optimizeRemoveNops()    //  must be done as the last step
         optimizeMultipleSequentialLineInstrs()      // once more

compiler/src/prog8/functions/BuiltinFunctions.kt

@@ -339,7 +339,7 @@ private fun builtinLen(args: List<IExpression>, position: Position, namespace:IN
     var argument = args[0].constValue(namespace, heap)
     if(argument==null) {
         if(args[0] !is IdentifierReference)
-            throw SyntaxError("len over weird argument ${args[0]}", position)
+            throw SyntaxError("len argument should be an identifier, but is ${args[0]}", position)
         val target = (args[0] as IdentifierReference).targetStatement(namespace)
         val argValue = (target as? VarDecl)?.value
         argument = argValue?.constValue(namespace, heap)

compiler/src/prog8/optimizing/ConstantFolding.kt

@@ -173,6 +173,21 @@ class ConstantFolding(private val namespace: INameScope, private val heap: HeapV
         }
     }
 
+    override fun process(memread: DirectMemoryRead): IExpression {
+        // @( &thing )  -->  thing
+        val addrOf = memread.addressExpression as? AddressOf
+        if(addrOf!=null)
+            return super.process(addrOf.identifier)
+        return super.process(memread)
+    }
+
+    override fun process(memwrite: DirectMemoryWrite): IExpression {
+        // @( &thing )  -->  thing
+        val addrOf = memwrite.addressExpression as? AddressOf
+        if(addrOf!=null)
+            return super.process(addrOf.identifier)
+        return super.process(memwrite)
+    }
 
     /**
      * Try to process a unary prefix expression.
@@ -673,5 +688,3 @@ class ConstantFolding(private val namespace: INameScope, private val heap: HeapV
         return assignment
     }
 }
-
-

compiler/src/prog8/optimizing/SimplifyExpressions.kt

@@ -18,6 +18,22 @@ class SimplifyExpressions(private val namespace: INameScope, private val heap: H
         return super.process(assignment)
     }
 
+    override fun process(memread: DirectMemoryRead): IExpression {
+        // @( &thing )  -->  thing
+        val addrOf = memread.addressExpression as? AddressOf
+        if(addrOf!=null)
+            return super.process(addrOf.identifier)
+        return super.process(memread)
+    }
+
+    override fun process(memwrite: DirectMemoryWrite): IExpression {
+        // @( &thing )  -->  thing
+        val addrOf = memwrite.addressExpression as? AddressOf
+        if(addrOf!=null)
+            return super.process(addrOf.identifier)
+        return super.process(memwrite)
+    }
+
     override fun process(expr: PrefixExpression): IExpression {
         if (expr.operator == "+") {
             // +X --> X

examples/test.p8

@@ -1,89 +1,16 @@
 %zeropage basicsafe
-%option enable_floats
-
-%import c64flt
-
 
 ~ main {
 
     sub start() {
 
-    ubyte[3] array1
+        ubyte[3] array1
-    ubyte[3] array2
+        str string1="hello"
-    ubyte[3] array3
 
-    str string1="hello"
+        uword x = &array1
-    str string2="bye"
 
-    uword pointer = &array1
+        word sl = len(@( &string1 ))
-    uword pointer2
-    uword pointer3
-    byte bt
-
-    pointer2 = &array2
-    pointer3 = &string1
-
-    uword[4] pointers = [&array1, &array2, &string1, &string2]
-
-
-    ptrsubasm("moet werken")
-    pointersub("moet werken")
-    myprintasm(string1)
-    myprintasm(string2)
-    myprintasm("moet werken3")
-    myprintasm("moet werken3")
-    myprintasm("moet werken4")
-
-    c64scr.print("this print must work\n")
-    c64.CHROUT('\n')
-
-    ptrsubasm(&array1)
-    ptrsubasm(&array2)
-    ptrsubasm(&string1)
-    ptrsubasm(&string2)
-    pointersub(&array1)
-    pointersub(&array2)
-    pointersub(&string1)
-    pointersub(&string2)
-    c64scr.print_uwhex(1, pointers[0])
-    c64.CHROUT(',')
-    c64scr.print_uwhex(1, pointers[1])
-    c64.CHROUT(',')
-    c64scr.print_uwhex(1, pointers[2])
-    c64.CHROUT(',')
-    c64scr.print_uwhex(1, pointers[3])
-
-    }
-
-    sub pointersub(uword arg) {
-        c64scr.print_uwhex(1, arg)
-        c64.CHROUT('\n')
-    }
-
-    asmsub ptrsubasm(uword arg @ AY) -> clobbers() -> () {
-        %asm {{
-            sec
-            jsr  c64scr.print_uwhex
-            lda  #13
-            jmp  c64.CHROUT
-        }}
-    }
-
-    asmsub myprintasm(str arg @ AY) -> clobbers() -> () {
-        %asm {{
-            sec
-            jsr  c64scr.print_uwhex
-            lda  #13
-            jmp  c64.CHROUT
-        }}
-    }
-
-}
-
-~ test {
-
-    sub testsub() {
-        uword[4] pointers = [&main.start.array1, &main.start.array2, &main.start.string1, &main.start.string2]   ; @todo make it possible to initialize array with pointers
 
+        c64scr.print_w(sl)      ; should be 5
     }
 }