int-to-utf8

Function Signature

(int-to-utf8 value)

• Input: int | uint
• Output: (string-utf8 40)

Why it matters

The int-to-utf8 function is crucial for:

1. Converting integer values to their UTF-8 string representations.
2. Facilitating the display and logging of numeric data in a more versatile encoding.
3. Enabling the use of numeric values in contexts that require UTF-8 strings.
4. Simplifying the process of creating human-readable outputs from numeric data.

When to use it

Use int-to-utf8 when you need to:

• Convert an integer or unsigned integer to a UTF-8 string.
• Display numeric values in a human-readable format.
• Log or store numeric data as UTF-8 strings.
• Prepare numeric data for concatenation with other UTF-8 strings.

Best Practices

• Ensure the integer value is within the range that can be represented as a string.
• Use meaningful variable names for better readability.
• Combine with other string functions for more complex string manipulations.
• Be aware of the maximum length of the resulting string (40 characters).

Practical Example: Logging a User's Balance

Let's implement a function that logs a user's balance as a UTF-8 string:

(define-map userBalances { userId: principal } { balance: uint })

(define-public (log-balance (user principal))
  (let
    (
      (balance (default-to u0 (map-get? userBalances { userId: user })))
      (balanceStr (int-to-utf8 balance))
    )
    (print balanceStr)
  )
)

;; Usage
(map-set userBalances { userId: tx-sender } { balance: u100 })
(log-balance tx-sender) ;; Logs "100"

This example demonstrates:

1. Using int-to-utf8 to convert a user's balance to a UTF-8 string.
2. Logging the string representation of the balance using print.
3. Handling the case where the user has no balance set.

Common Pitfalls

1. Assuming the resulting string will always fit within 40 characters.
2. Forgetting to handle cases where the integer value is not set or is zero.
3. Using int-to-utf8 in performance-critical sections without considering the overhead.
4. Not combining with other string functions for more complex manipulations.

Related Functions

• print: Used to log or display string values.
• concat: Used to concatenate multiple strings.
• default-to: Used to provide default values for optional types.

Conclusion

The int-to-utf8 function is a powerful tool for converting integer values to their UTF-8 string representations in Clarity smart contracts. It enables developers to create human-readable outputs from numeric data, facilitating logging, display, and storage of numeric values as strings. When used effectively, int-to-utf8 enhances the readability and usability of numeric data within your smart contract code.