Built-in Functions

Here is a list of Hop's built-in functions. Because Hop functions can be overloaded, some of them have multiple signatures. Functions with brackets after their names are generic. Generic functions are described in the generics chapter.

• . - duplicate a value on the stack

  • fn .[T] T -> T T

• ~ - pop a value from the stack

  • fn ~[T] T

• @ - get a pointer to stack's top value

  • fn @[T] T -> T *T

• put - print a primitive value

  • fn put int
  • fn put float
  • fn put byte
  • fn put bool

• putln - print a primitive value with a newline

  • fn putln int
  • fn putln float
  • fn putln byte
  • fn putln bool

• puts - print a string

  • fn puts *byte

• putlns - print a string with a newline

  • fn putlns *byte

• putc - print a character

  • fn putc int

• putlnc - print a character with a newline

  • fn putlnc int

• putp - print a pointer

  • fn putp[T] *T

• putlnp - print a pointer with a newline

  • fn putlnp[T] *T

• ln - print a newline

  • fn ln

• read - read a pointer

  • fn read[T] *T -> T

• write - write to a pointer

  • fn write[T] *T T

• exit - exit the program with the given exit code

  • fn exit int

• realloc - reallocate an allocated pointer

  • fn realloc[T] *T int -> *T

• free - free an allocated pointer

  • fn free[T] *T

• copy - copy values from one pointer to another

  • fn copy[T] let dst: *T src: *T n: int

• pow - raise one float to the power of another

  • fn pow float float -> float

• random - generate a random float in [0, 1)

  • fn random -> float

• time - get the current time in seconds

  • fn time -> float

• stdin - read a line from stdin into a heap-allocated string (or return null on failure)

  • fn -> *byte

• to_byte - convert a number to a byte

  • fn to_byte int -> byte
  • fn to_byte float -> byte

• to_int - convert a number to an int

  • fn to_int byte -> int
  • fn to_int float -> int
  • fn to_int[T] *T -> int

• to_float - convert a number to a float

  • fn to_float byte -> float
  • fn to_float int -> float

• + - add two numbers

  • fn + byte byte -> byte
  • fn + byte int -> int
  • fn + byte float -> float
  • fn + int byte -> int
  • fn + int int -> int
  • fn + int float -> float
  • fn + float byte -> float
  • fn + float int -> float
  • fn + float float -> float
  • fn +[T] *T int -> *T
  • fn +[T] int *T -> *T

• - - subtract two numbers

  • fn - byte byte -> byte
  • fn - byte int -> int
  • fn - byte float -> float
  • fn - int byte -> int
  • fn - int int -> int
  • fn - int float -> float
  • fn - float byte -> float
  • fn - float int -> float
  • fn - float float -> float
  • fn -[T] *T int -> *T
  • fn -[T] *T *T -> int

• * - multiply two numbers

  • fn * byte byte -> byte
  • fn * byte int -> int
  • fn * byte float -> float
  • fn * int byte -> int
  • fn * int int -> int
  • fn * int float -> float
  • fn * float byte -> float
  • fn * float int -> float
  • fn * float float -> float

• / - divide two numbers

  • fn / byte byte -> byte
  • fn / byte int -> int
  • fn / byte float -> float
  • fn / int byte -> int
  • fn / int int -> int
  • fn / int float -> float
  • fn / float byte -> float
  • fn / float int -> float
  • fn / float float -> float

• % - calculate the modulus of two numbers

  • fn % byte byte -> byte
  • fn % byte int -> int
  • fn % byte float -> float
  • fn % int byte -> int
  • fn % int int -> int
  • fn % int float -> float
  • fn % float byte -> float
  • fn % float int -> float
  • fn % float float -> float

• & - logical and

  • fn & byte byte -> byte
  • fn & int int -> int
  • fn & bool bool -> bool

• ^ - logical xor

  • fn ^ byte byte -> byte
  • fn ^ int int -> int
  • fn ^ bool bool -> bool

• | - logical or

  • fn | byte byte -> byte
  • fn | int int -> int
  • fn | bool bool -> bool

• << - bit shift left

  • fn << byte byte -> byte
  • fn << byte int -> byte
  • fn << int byte -> int
  • fn << int int -> int

• >> - bit shift right

  • fn >> byte byte -> byte
  • fn >> byte int -> byte
  • fn >> int byte -> int
  • fn >> int int -> int

• == - check if two numbers are equal

  • fn == byte byte -> bool
  • fn == byte int -> bool
  • fn == byte float -> bool
  • fn == int byte -> bool
  • fn == int int -> bool
  • fn == int float -> bool
  • fn == float byte -> bool
  • fn == float int -> bool
  • fn == float float -> bool
  • fn ==[T] *T *T -> bool

• != - check if two numbers are not equal

  • fn != byte byte -> bool
  • fn != byte int -> bool
  • fn != byte float -> bool
  • fn != int byte -> bool
  • fn != int int -> bool
  • fn != int float -> bool
  • fn != float byte -> bool
  • fn != float int -> bool
  • fn != float float -> bool
  • fn !=[T] *T *T -> bool

• < - compare two numbers

  • fn < byte byte -> bool
  • fn < byte int -> bool
  • fn < byte float -> bool
  • fn < int byte -> bool
  • fn < int int -> bool
  • fn < int float -> bool
  • fn < float byte -> bool
  • fn < float int -> bool
  • fn < float float -> bool
  • fn <[T] *T *T -> bool

• <= - compare two numbers

  • fn <= byte byte -> bool
  • fn <= byte int -> bool
  • fn <= byte float -> bool
  • fn <= int byte -> bool
  • fn <= int int -> bool
  • fn <= int float -> bool
  • fn <= float byte -> bool
  • fn <= float int -> bool
  • fn <= float float -> bool
  • fn <=[T] *T *T -> bool

• > - compare two numbers

  • fn > byte byte -> bool
  • fn > byte int -> bool
  • fn > byte float -> bool
  • fn > int byte -> bool
  • fn > int int -> bool
  • fn > int float -> bool
  • fn > float byte -> bool
  • fn > float int -> bool
  • fn > float float -> bool
  • fn >[T] *T *T -> bool

• >= - compare two numbers

  • fn >= byte byte -> bool
  • fn >= byte int -> bool
  • fn >= byte float -> bool
  • fn >= int byte -> bool
  • fn >= int int -> bool
  • fn >= int float -> bool
  • fn >= float byte -> bool
  • fn >= float int -> bool
  • fn >= float float -> bool
  • fn >=[T] *T *T -> bool

• ! - logical not

  • fn ! bool -> bool
  • fn ! byte -> byte
  • fn ! int -> int

• neg - negate a number

  • fn neg int -> int
  • fn neg float -> float

• strcmp - compare 2 strings

  • fn strcmp *byte *byte -> int

• streq - check if 2 strings are equal

  • fn streq *byte *byte -> bool

• strcpy - copy a string from one allocation to another

  • fn strcpy let dst: *byte src: *byte

• strlen - find a string's length

  • fn strlen *byte -> int

• read_file - read a file into a heap-allocated string (or return null on failure)

  • fn read_file *byte -> *byte

• write_to_file - write a string to a file (and return true on success)

  • fn write_to_file let text: *byte file_path: *byte -> bool

• append_to_file - append a string to a file (and return true on success)

  • fn append_to_file let text: *byte file_path: *byte -> bool