feat: add [x; _] literal

crates/erg_compiler/lib/std/_erg_array.py

@@ -3,6 +3,8 @@ from _erg_range import Range
 from _erg_nat import NatMut
 from _erg_int import IntMut
 from _erg_contains_operator import contains_operator
+from _erg_result import is_ok
+from _erg_result import Error
 
 class Array(list):
     def try_new(arr):  # -> Result[Array]
@@ -11,6 +13,21 @@ class Array(list):
         else:
             return Error("not a list")
 
+    def generic_try_new(arr, cls = None):  # -> Result[Array]
+        if cls is None:
+            return Array.try_new(arr)
+        else:
+            elem_t = cls.__args__[0]
+            elems = []
+            for elem in arr:
+                # TODO: nested check
+                elem = elem_t.try_new(elem)
+                if is_ok(elem):
+                    elems.append(elem)
+                else:
+                    return Error("not a " + str(elem_t))
+            return Array(elems)
+
     def dedup(self, same_bucket=None):
         if same_bucket is None:
             return Array(list(set(self)))
@@ -77,3 +94,8 @@ class Array(list):
 
     def update_nth(self, index, f):
         self[index] = f(self[index])
+
+class UnsizedArray:
+    elem: object
+    def __init__(self, elem):
+        self.elem = elem

crates/erg_compiler/lib/std/_erg_contains_operator.py

@@ -12,6 +12,8 @@ def contains_operator(y, elem) -> bool:
     elif is_type(y):
         if _isinstance(elem, y):
             return True
+        elif hasattr(y, "generic_try_new"):
+            return is_ok(y.generic_try_new(elem, y))
         elif hasattr(y, "try_new") and is_ok(y.try_new(elem)):
             return True
         elif hasattr(y, "__origin__") and hasattr(y.__origin__, "type_check"):

crates/erg_compiler/lib/std/_erg_std_prelude.py

@@ -13,7 +13,7 @@ from _erg_nat import Nat, NatMut
 from _erg_bool import Bool
 from _erg_bytes import Bytes
 from _erg_str import Str, StrMut
-from _erg_array import Array
+from _erg_array import Array, UnsizedArray
 from _erg_dict import Dict
 from _erg_set import Set
 from _erg_contains_operator import contains_operator