Built-in Functions

Harbor has one built-in function: print. The respond keyword also uses call syntax but is a language keyword, not a function.

print(value)

Prints a value to standard output followed by a newline.

print("Hello, world!")
print(42)
print(10 + 20)

Output:

Hello, world!
42
30

print takes exactly one argument. It works with strings and numbers. Passing other internal types (like None) may produce no output.

respond

While respond uses function-call-like syntax, it is a language keyword. It can only be used inside route handlers.

get "/" {
    respond "OK"
}

respond sends its argument as the HTTP response body with a 200 OK status. The argument must evaluate to a string.

Both of these forms are valid:

respond "hello"
respond("hello")

See Routes for more details on using respond in handlers.