🐐 String indexing and slicing

centvrion/ast_nodes.py

@@ -833,6 +833,17 @@ class ArrayIndex(Node):
       if k not in d:
         raise CentvrionError(f"Key not found in dict")
       return vtable, d[k]
+    if isinstance(array, ValStr):
+      if isinstance(index, ValInt):
+        i = index.value()
+      elif isinstance(index, ValFrac) and index.value().denominator == 1:
+        i = index.value().numerator
+      else:
+        raise CentvrionError("String index must be a number")
+      s = array.value()
+      if i < 1 or i > len(s):
+        raise CentvrionError(f"Index {i} out of range for string of length {len(s)}")
+      return vtable, ValStr(s[i - 1])
     if not isinstance(array, ValList):
       raise CentvrionError("Cannot index a non-array value")
     if isinstance(index, ValInt):
@@ -877,6 +888,16 @@ class ArraySlice(Node):
     vtable, array = self.array.eval(vtable)
     vtable, from_val = self.from_index.eval(vtable)
     vtable, to_val = self.to_index.eval(vtable)
+    if isinstance(array, ValStr):
+      from_int = _to_index_int(from_val)
+      to_int = _to_index_int(to_val)
+      s = array.value()
+      if from_int < 1 or to_int > len(s) or from_int > to_int:
+        raise CentvrionError(
+          f"Slice [{from_int} VSQVE {to_int}] out of range"
+          f" for string of length {len(s)}"
+        )
+      return vtable, ValStr(s[from_int - 1 : to_int])
     if not isinstance(array, ValList):
       raise CentvrionError("Cannot slice a non-array value")
     from_int = _to_index_int(from_val)