#828: Audit and make documentation for command lpop consistent (#1053)

docs/src/content/docs/commands/LPOP.md

@@ -1,119 +1,133 @@
 ---
 title: LPOP
-description: Documentation for the DiceDB command LPOP
+description: The `LPOP` command in DiceDB removes and returns the first element of a list at a specified key. This command is ideal for implementing queue-like data structures that process elements in a First-In-First-Out (FIFO) order.
 ---
 
-The `LPOP` command is used to remove and return the first element of a list stored at a specified key in DiceDB. This command is useful for implementing queue-like structures where elements are processed in a First-In-First-Out (FIFO) order.
+The `LPOP` command in DiceDB removes and returns the first element of a list at a specified key. This command is ideal for implementing queue-like data structures that process elements in a First-In-First-Out (FIFO) order.
 
 ## Syntax
 
-```
+```plaintext
 LPOP key
 ```
 
 ## Parameters
 
-- `key`: The key of the list from which the first element will be removed and returned. The key must be a valid string.
+| Parameter   | Description                                                                     | Type    | Required |
+| ----------- | --------------------------------------------------------------------------------| ------- | -------- |
+| `key`       | The key of the list from which the first element will be removed and returned.  | String  | Yes      |
+
+
 
 ## Return Value
 
-- `String`: The value of the first element in the list, if the list exists and is not empty.
-- `nil`: If the key does not exist or the list is empty.
+| Condition                                      | Return Value                                                                              |
+|------------------------------------------------|-------------------------------------------------------------------------------------------|
+| Command is successful                          | `String` The value of the first element in the list, if the list exists and is not empty. |
+| If the key does not exist or the list is empty | `nil`                                                                                     |
+| Syntax or specified constraints are invalid    |  error                                                                                    |
 
-## Behaviour
 
-When the `LPOP` command is executed:
 
-1. If the key exists and is associated with a list, the first element of the list is removed and returned.
-2. If the key does not exist, the command returns `nil`.
-3. If the key exists but is not associated with a list, an error is returned.
-4. If the list is empty, the command returns `nil`.
+## Behavior
 
-## Error Handling
+- When the `LPOP` command is executed, DiceDB checks if the key exists and is associated with a list. If so, the first element of the list is removed and returned.
+- If the key does not exist or the list is empty, the command returns `nil`.
+- If the key exists but is not associated with a list, a `WRONGTYPE` error is returned.
+- If more than one argument is passed, an error is returned.
 
-- `WRONGTYPE Operation against a key holding the wrong kind of value`: This error is raised if the key exists but is not associated with a list. For example, if the key is associated with a string, set, or hash, this error will be returned.
+## Errors
 
-## Example Usage
+1. `Wrong type of key`
 
-### Example 1: Basic Usage
+When the `LPOP` command is executed for a key that exists but is not associated with a list, an error is returned. This error occurs if the key is associated with a type other than a list, such as a string or set.
 
-```DiceDB
-RPUSH mylist "one" "two" "three"
-LPOP mylist
+```bash
+127.0.0.1:7379> LPOP mystring
+(error) WRONGTYPE Operation against a key holding the wrong kind of value
 ```
+2. `Wrong number of arguments`
 
-`Output:`
+If the `LPOP` command is executed with more than one key or no key, the following error is returned:
 
+```bash
+127.0.0.1:7379> LPOP
+(error) ERR wrong number of arguments for 'lpop' command
 ```
-"one"
+
+```bash
+127.0.0.1:7379> LPOP mylist secondlist
+(error) ERR wrong number of arguments for 'lpop' command
 ```
 
-`Explanation:`
+## Example Usage
 
-- The list `mylist` initially contains the elements \["one", "two", "three"\].
-- The `LPOP` command removes and returns the first element, which is "one".
-- The list `mylist` now contains \["two", "three"\].
+### Basic Usage
+Setting a list `mylist` with elements \["one", "two", "three"\].
 
-### Example 2: List is Empty
+```bash
+RPUSH mylist "one" "two" "three"
+```
+Removing the first element from the list `mylist`
 
-```DiceDB
-RPUSH mylist "one"
-LPOP mylist
+```bash
 LPOP mylist
+"one"
 ```
 
-`Output:`
+The list `mylist` now contains \["two", "three"\].
 
-```
-"one"
-(nil)
+If the LPOP command is executed one more time:
+```bash
+LPOP mylist
+"two"
 ```
 
-`Explanation:`
+The list `mylist` now contains \["three"\].
 
-- The list `mylist` initially contains the element \["one"\].
-- The first `LPOP` command removes and returns "one".
-- The second `LPOP` command returns `nil` because the list is now empty.
 
-### Example 3: Key Does Not Exist
 
-```DiceDB
-LPOP nonexistinglist
-```
+### Empty List or Non-Existent Key
 
-`Output:`
+Returns `(nil)` if the list is empty or the provided key is non-existent
 
-```
+```bash
+LPOP emptylist
 (nil)
 ```
 
-`Explanation:`
 
-- The key `nonexistinglist` does not exist in the database.
-- The `LPOP` command returns `nil`.
 
-### Example 4: Key is Not a List
 
-```DiceDB
+### Key is Not a List
+
+Setting a key `mystring` with the value `hello`:
+
+```bash
 SET mystring "hello"
-LPOP mystring
+OK
 ```
 
-`Output:`
+Executing `LPOP` command on any key that is not associated with a List type will result in an error:
 
-```
+```bash
+LPOP mystring
 (error) WRONGTYPE Operation against a key holding the wrong kind of value
 ```
 
-`Explanation:`
+### Wrong Number of Arguments
+
+Passing more than one key will result in an error:
 
-- The key `mystring` is associated with a string value "hello".
-- The `LPOP` command returns an error because `mystring` is not a list.
+```bash
+LPOP mylist secondlist
+(error) ERR wrong number of arguments for 'lpop' command
+```
 
-## Best Practices
+### Notes
 
-- Ensure that the key you are using with `LPOP` is associated with a list to avoid errors.
-- Use `EXISTS` command to check if a key exists before using `LPOP` to handle cases where the key might not exist.
+- The key used with the `LPOP` command should be associated with a list to avoid any potential errors.
+- Use the `EXISTS` command to check if a key exists before using `LPOP` to handle cases where the key might not exist.
 - Consider using `LLEN` to check the length of the list if you need to handle empty lists differently.
 
 ## Related Commands