From 9ac8248609da5d0bbcf7ccfaf63325a0a44c6b39 Mon Sep 17 00:00:00 2001
From: Shunsuke Shibayama <sbym1346@gmail.com>
Date: Sun, 27 Nov 2022 16:35:50 +0900
Subject: [PATCH] Implement some primitive types methods

---
 compiler/erg_compiler/lib/std/_erg_array.py |  4 +++
 compiler/erg_compiler/lib/std/_erg_nat.py   |  6 +++++
 compiler/erg_compiler/lib/std/_erg_str.py   | 29 +++++++++++++++++++++
 3 files changed, 39 insertions(+)

diff --git a/compiler/erg_compiler/lib/std/_erg_array.py b/compiler/erg_compiler/lib/std/_erg_array.py
index 2d5af648..43c6f1c4 100644
--- a/compiler/erg_compiler/lib/std/_erg_array.py
+++ b/compiler/erg_compiler/lib/std/_erg_array.py
@@ -1,4 +1,8 @@
 class Array(list):
+    def dedup(self):
+        return Array(list(set(self)))
+    def dedup_by(self, f):
+        return Array(list(set(map(f, self))))
     def push(self, value):
         self.append(value)
         return self
diff --git a/compiler/erg_compiler/lib/std/_erg_nat.py b/compiler/erg_compiler/lib/std/_erg_nat.py
index d47c36b0..dbaefc4e 100644
--- a/compiler/erg_compiler/lib/std/_erg_nat.py
+++ b/compiler/erg_compiler/lib/std/_erg_nat.py
@@ -10,3 +10,9 @@ class Nat(int):
     def times(self, f):
         for _ in range(self):
             f()
+
+    def saturating_sub(self, other: Nat):
+        if self > other:
+            return self - other
+        else:
+            return 0
diff --git a/compiler/erg_compiler/lib/std/_erg_str.py b/compiler/erg_compiler/lib/std/_erg_str.py
index 74b76039..6d278376 100644
--- a/compiler/erg_compiler/lib/std/_erg_str.py
+++ b/compiler/erg_compiler/lib/std/_erg_str.py
@@ -8,3 +8,32 @@ class Str(str):
             return Str(s)
         else:
             return Error("Str can't be other than str")
+    def get(self, i: int):
+        if len(self) > i:
+            return Str(self[i])
+        else:
+            return None
+
+class StrMut(Str):
+    def try_new(s: str):
+        if isinstance(s, str):
+            return StrMut(s)
+        else:
+            return Error("Str! can't be other than str")
+    def clear(self):
+        self = ""
+    def pop(self):
+        if len(self) > 0:
+            last = self[-1]
+            self = self[:-1]
+            return last
+        else:
+            return Error("Can't pop from empty `Str!`")
+    def push(self, c: str):
+        self += c
+    def remove(self, idx: int):
+        char = self[idx]
+        self = self[:idx] + self[idx+1:]
+        return char
+    def insert(self, idx: int, c: str):
+        self = self[:idx] + c + self[idx:]