replace pointers with slices

test/stdlib.ul

@@ -5,57 +5,31 @@ const nat U16_MAX = 65535;
 byte[10000] heap;
 nat heap_allocated = 0;
 
-function malloc(nat size) ref byte[] {
+subroutine alloc(nat size) byte[] {
     nat pos = heap_allocated;
     heap_allocated = heap_allocated + size;
-    return ref heap[pos];
+    return heap[pos:pos + size];
 }
 
-function free() {
+subroutine heap_reset() {
     heap_allocated = 0;
 }
 
-function memcpy(ref byte[] to, ref byte[] from, nat length) {
-    for (nat i = 0; i < length; i++) {
-        to[i] = from[i];
-    }
-	return ptr;
-}
-
-function mallocpy(ref byte[] from, nat length) ref byte[] {
-    ref byte[] ptr = malloc(length);
-    for (nat i = 0; i < length; i++) {
-        ptr[i] = from[i];
-    }
-	return ptr;
-}
-
-
-/**
- * Print with a newline
- */
-function pln(str string) {
-    for (byte c in string) {
-     write = c;
-    }
-    write = '\n';
-}
-
 /**
  * Concatinates 2 strings
  */
 function strcat(str src1, str src2) str {
-    str result = malloc(src1.length + src2.length);
-    memcpy(ref result[0], ref src1[0]);
-    memcpy((ref result[0] + src1.length), ref src2[0]);
+    str result = alloc(src1.length + src2.length) as str;
+    result[0:src1.length] = src1;
+    result[src1.length:] = src2;
     return result;
 }
 
 /**
  * finds index of string, -1 if not found
  */
-function stridx(str haystack, char needle) int {
-   int i = -1;
+function stridx(str haystack, char needle) nat {
+   nat i = -1;
    for (char c in haystack) {
      i = i + 1;
      if (c == needle) {
@@ -70,7 +44,7 @@ function stridx(str haystack, char needle) int {
  */
 function streq(str src1, str src2) bool {
   if (src1.length != src2.length) return false;
-  for (int i=0; src1.length; i++) {
+  for (nat i=0; src1.length; i++) {
     if (src1[i] != src2[i]) return false; 
   }
   return true;
@@ -79,21 +53,31 @@ function streq(str src1, str src2) bool {
 /**
  * Slice string
  */
-function slice(str src, int start, int stop) str {
-   int len = stop - start;
-   str result = malloc(len); 
-   for (int i=start; i<stop; i++) {
+function slice(str src, nat start, nat stop) str {
+   nat len = stop - start;
+   str result = alloc(len) as str; 
+   for (nat i=start; i<stop; i++) {
      result[i] = src[i];
    }
    return result;
 }
 
+/**
+ * Print with a newline
+ */
+function pln(str string) {
+    for (byte c in string) {
+     write = c;
+    }
+    write = '\n';
+}
+
 /**
  * int to string
  */
 function itos(int src) str {
-	byte buffer[6];
-	nat i = 6;
+  byte buffer[6];
+  nat i = 6;
   bool neg = n < 0;
 
   if (neg) n = -n;
@@ -105,8 +89,8 @@ function itos(int src) str {
 
   if(neg) buffer[--i] = '-';
 
-  str result = malloc(6 - i); 
-  memcpy(result, &buffer[0] + i, 6 - i);
+  str result = alloc(6 - i) as str; 
+  result[0:] = buffer[i:6 - i];
   return result;
 }
 
@@ -122,8 +106,8 @@ function ntos(nat src) str {
       n /= 10;
   } while(n > 0);
 
-  str result = malloc(5 - i); 
-  memcpy(result, &buffer[0] + i, 5 - i);
+  str result = alloc(6 - i) as str; 
+  result[0:] = buffer[i:6 - i];
   return result;
 }