Fix indexing return type and casting to and from a char

reid/lib/std.reid

@@ -31,6 +31,16 @@ pub fn new_string() -> String {
     String {
         inner: allocate(0),
         length: 0,
+        max_length: 0,
+    }
+}
+
+pub fn from_str(str: *char) -> String {
+    let length = str_length(str, 0);
+    String {
+        inner: str,
+        length: length,
+        max_length: length
     }
 }
 
@@ -42,13 +52,17 @@ pub fn add_char(string: &mut String, c: char) {
         free((*string).inner as *u8);
         (*string).max_length = (*string).max_length + 4;
         (*string).inner = new;
-
     }
+
     (*string).inner[(*string).length] = c;
     (((*string).inner) as *u8)[((*string).length + 1)] = 0;
     (*string).length = (*string).length + 1;
 }
 
+pub fn free_string(string: &mut String) {
+    free((*string).inner as *u8);
+}
+
 fn copy_bits(from: *char, to: *char, pos: u64, max: u64) -> u8 {
     if (pos >= max) {
         return 0;
@@ -57,6 +71,9 @@ fn copy_bits(from: *char, to: *char, pos: u64, max: u64) -> u8 {
     return copy_bits(from, to, pos + 1, max);
 }
 
-pub fn free_string(string: &mut String) {
-    free((*string).inner as *u8);
+fn str_length(string: *char, position: u32) -> u32 {
+    if ((string[position] as u8) == 0) {
+        return 0;
+    }
+    return str_length(string, position + 1) + 1;
 }

reid/src/codegen.rs

@@ -1083,7 +1083,9 @@ impl mir::Expression {
                             )),
                             _ => panic!(),
                         },
-                        (TypeKind::UserPtr(_), TypeKind::UserPtr(_)) => Some(StackValue(
+                        (TypeKind::UserPtr(_), TypeKind::UserPtr(_))
+                        | (TypeKind::Char, TypeKind::U8)
+                        | (TypeKind::U8, TypeKind::Char) => Some(StackValue(
                             val.0.derive(
                                 scope
                                     .block

reid/src/mir/implement.rs

@@ -394,6 +394,8 @@ impl Expression {
                 let expr_type = expression.return_type(refs, mod_id)?;
                 if let TypeKind::Array(elem_ty, _) = expr_type.1.resolve_weak(refs) {
                     Ok((ReturnKind::Soft, *elem_ty))
+                } else if let TypeKind::UserPtr(_) = expr_type.1.resolve_weak(refs) {
+                    Ok((ReturnKind::Soft, expr_type.1))
                 } else {
                     Err(ReturnTypeOther::IndexingNonArray(expression.1))
                 }