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(guile-tut.info)Jump Start

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Jump Start
**********

Before giving an overview of Guile, I present some simple commands and
programs that you can type to get going immediately.

  Start by invoking the Guile interpreter (usually you do this by just
typing `guile').  Then type (or paste) the following expressions at the
prompt; the interpreter's response is preceded (in this manual) by =>.

     <shell-prompt> guile

     (+ 20 35)
     => 55
     (define (recursive-factorial n)
              (if (= n 0)
                  1
                 (* n (recursive-factorial (- n 1)))))
     (recursive-factorial 5)
     => 120
     (recursive-factorial 500)
     => 1220136825991110068701238785423046926253574342803192842192413588
        3858453731538819976054964475022032818630136164771482035841633787
        2207817720048078520515932928547790757193933060377296085908627042
        9174547882424912726344305670173270769461062802310452644218878789
        4657547771498634943677810376442740338273653974713864778784954384
        8959553753799042324106127132698432774571554630997720278101456108
        1188373709531016356324432987029563896628911658974769572087926928
        8712817800702651745077684107196243903943225364226052349458501299
        1857150124870696156814162535905669342381300885624924689156412677
        5654481886506593847951775360894005745238940335798476363944905313
        0623237490664450488246650759467358620746379251842004593696929810
        2226397195259719094521782333175693458150855233282076282002340262
        6907898342451712006207714640979456116127629145951237229913340169
        5523638509428855920187274337951730145863575708283557801587354327
        6888868012039988238470215146760544540766353598417443048012893831
        3896881639487469658817504506926365338175055478128640000000000000
        0000000000000000000000000000000000000000000000000000000000000000
        00000000000000000000000000000000000000000000000
     <control-D>

  In this example we did some simple arithmetic `(+ 20 35)' and got the
answer `55'.  Then we coded the classic (and rather wasteful) factorial
algorithm, and got a glimpse of Scheme's nice _bignumbers_ by asking
for the factorial of 1000.  Then we quit with `(quit)'.

  This is the most basic use of Guile: a simple Scheme interpreter.  In
the rest of this tutorial I will show you how Guile has many facets: it
is also an _extensible_ interpreter (to which many features can be
easilly added) and an _embeddable_ interpreter (which can be invoked
from your C programs).