Implement Str.chars and Str.substr

CodeGen.pm

@@ -38,6 +38,9 @@ use 5.010;
             { islist       => [f => 'Boolean'] },
         'CLRImportObject' =>
             { val          => [f => 'Object'] },
+        'String' =>
+            { Length       => [f => 'Int32'],
+              Substring    => [m => 'String'] },
 
         'Kernel.SlurpyHelper'  => [c => 'List<Variable>'],
         'Kernel.Bind'          => [c => 'Void'],

setting

@@ -174,6 +174,14 @@ my class Num {
 my class Str {
     method Str () { self }
     method ACCEPTS($t) { self eq $t }
+    method chars() { Q:CgOp {
+        (box Num (cast Double (getfield Length (unbox String (@ (l self))))))
+    } }
+    method substr($from, $len) { Q:CgOp {
+        (box Str (rawcall [unbox String (@ (l self))] Substring
+                    [cast Int32 (unbox Double (@ (l $from)))]
+                    [cast Int32 (unbox Double (@ (l $len)))]))
+    } }
 }
 my class Blob { }
 my class Char { }

test.pl

@@ -10,7 +10,7 @@ ($num)
     say ("1.." ~ $num);
 }
 
-plan 91;
+plan 93;
 
 ok 1, "one is true";
 ok 2, "two is also true";
@@ -286,3 +286,8 @@ ($num)
     ok foo == 42, "constants without sigils work";
     ok $bar == 51, "constants with sigils work";
 }
+
+{
+    ok "Hello".substr(1,3) eq "ell", "substr works";
+    ok "Hello".chars == 5, ".chars works";
+}