Crafting Interpreters

Builtin Types

• Number - 64 bit float
• Str
• Bool
• Array
• Function
• Nil

Native Functions

In case of errors or invalid arguments, a global error variable named "errString" is set with the error message and the function returns nil. Otherwise, the global error variable is set to nil.

1. clock() -> Number

   Returns the current epoch in milliseconds.

2. print(Str)

   Prints the given string to the output.

3. readnumber(String) -> Number

   Reads a number from the input, displaying the given string as a prompt.

4. input(String) -> Str

   Reads a string from the input, displaying the optional given string as a prompt.

5. typeof(Any) -> String

   Returns the type of the given value.

6. str(Any) -> String

   Converts the given value to a string.

7. int(Any) -> Number

   Converts the given value (number, bool, or string) to an integer.

8. float(Any) -> Number

   Converts the given value (number, bool, or string) to a float.

9. bool(Any) -> Bool

   Converts the given value to a boolean following pythonic truthiness rules.

10. stringat(String, Number) -> String

    Returns the character at the given index in the string.

11. len(Str/Array) -> Number

    Returns the length of the given string or array.

12. ceil(Number) -> Number

    Returns the smallest integer greater than or equal to the given number.

13. floor(Number) -> Number

    Returns the largest integer less than or equal to the given number.

14. abs(Number) -> Number

    Returns the absolute value of the given number.

15. rand() -> Number

    Returns a 32-bit unsigned integer (as Number).

16. sort(Array)

    Sorts an array of numbers in ascending order. If the array has non-numbers, it's an error.

17. indexof(Array, Any) -> Number

    Returns the index of the given value in the array. If the value is not found, returns the length of the array.