Copy cog from https://gist.github.com/vierofernando/c5796a78292b949341c98a5deaee8eda

jarvis/cogs/dev.py

@@ -5,8 +5,11 @@ import re
 import ulid
 import base64
 import subprocess
-import traceback
+from inspect import getsource
-import inspect
+import discord
+import time
+import sys
+import os
 from discord.ext import commands
 from jarvis.utils import build_embed, convert_bytesize
 from jarvis.utils.field import Field
@@ -238,15 +241,70 @@ class DevCog(commands.Cog):
         output = subprocess.check_output(["cloc", "."]).decode("UTF-8")
         await ctx.send(f"```\n{output}\n```")
 
-    @commands.command(name="eval")
+    def resolve_variable(self, variable):
+        if hasattr(variable, "__iter__"):
+            var_length = len(list(variable))
+            if (var_length > 100) and (not isinstance(variable, str)):
+                return f"<a {type(variable).__name__} iterable with more than 100 values ({var_length})>"
+            elif not var_length:
+                return f"<an empty {type(variable).__name__} iterable>"
+
+        if (not variable) and (not isinstance(variable, bool)):
+            return f"<an empty {type(variable).__name__} object>"
+        return (
+            variable
+            if (len(f"{variable}") <= 1000)
+            else f"<a long {type(variable).__name__} object with the length of {len(f'{variable}'):,}>"
+        )
+
+    def prepare(self, string):
+        arr = (
+            string.strip("```")
+            .replace("py\n", "")
+            .replace("python\n", "")
+            .split("\n")
+        )
+        if not arr[::-1][0].replace(" ", "").startswith("return"):
+            arr[len(arr) - 1] = "return " + arr[::-1][0]
+        return "".join(f"\n\t{i}" for i in arr)
+
+    @commands.command(pass_context=True, aliases=["eval", "exec", "evaluate"])
     @commands.is_owner()
     async def _eval(self, ctx, *, code: str):
-        code = f"async def fn():{code}"
+        silent = "-s" in code
+
+        code = self.prepare(code.replace("-s", ""))
+        args = {
+            "discord": discord,
+            "sauce": getsource,
+            "sys": sys,
+            "os": os,
+            "imp": __import__,
+            "this": self,
+            "ctx": ctx,
+        }
+
         try:
-            output = exec(code, globals(), locals())
+            exec(f"async def func():{code}", args)
-        except Exception:
+            a = time()
-            output = traceback.format_exc()
+            response = await eval("func()", args)
-        await ctx.send(f"```{output}```")
+            if (
+                silent
+                or (response is None)
+                or isinstance(response, discord.Message)
+            ):
+                del args, code
+                return
+
+            await ctx.send(
+                f"```py\n{self.resolve_variable(response)}````{type(response).__name__} | {(time() - a) / 1000} ms`"
+            )
+        except Exception as e:
+            await ctx.send(
+                f"Error occurred:```\n{type(e).__name__}: {str(e)}```"
+            )
+
+        del args, code, silent
 
 
 def setup(bot):