simple example doesn't work

[JeNeSuisPasDave]

This simple example from Teach Yourself Scheme in Fixnum Days does not work.

If I put the code in a "hello.scm" file and run picrin hello.scm I get this:

$ picrin hello.scm
error: "uninitialized global variable: 2.16356e-314" 2.16356e-314
  at (anonymous lambda) (unknown location)
  at (anonymous lambda) (native function)

If I type the code into the REPL, I get this:

$ picrin
> (begin
  (display "Hello, World!")
  (newline))
Hello, World!
#undefined
> 

Yep, I'm trying to learn Scheme. Perhaps picrin isn't the best tool for that ...

[KeenS]

@JeNeSuisPasDave
That's because picrin is R7RS implementation. Unlike R5RS, R7RS scheme separates functions into libraries and you need to explicitly import them. To run your example, put import like below,

(import (scheme base)
        (scheme write))

(begin
 (display "Hello, World!")
 (newline))

(scheme base) is the basis library and (scheme write) is a IO library. This is R7RS way.
However, if you want to learn R5RS scheme, you can use (scheme r5rs) library, which is compat library to R5RS scheme,

(import (scheme r5rs))

(begin
 (display "Hello, World!")
 (newline))

Bests

[JeNeSuisPasDave]

Forgot to say "thanks". :-/