( Library of Forth code. )

( Push a 42, and check it after all is done, just to make sure none of
  this code leaves anything on the stack. )
42

( TODO:
    - Make sure that dp is aligned before definitions are started.
      Do this by redefining colon to take care of the alignment and
      then call the old colon. )

( Used mainly in debugging tests. )
: dup4 dup dup dup dup ;


( Stack and dp display. )
: show dup . cr ;
: showr r@ . cr ;
: ps 10 print_stack ;
: pr 10 print_rstack ;
: prs r> 10 print_rstack >r ;
: dp ( Just an alias. ) here ;
: ph ( Show where we are. ) here . cr ;


( Storing things in the dictionary by hand. )
: size_t ( The length of one entry. ) 4 ;             
: dp+ ( Increment dp by exactly one entry. ) size_t allot ;
: dp!+ ( [ n -- ] Store a value in dp and advance. ) here ! dp+ ;

( Ahhhh. )
: recurse last dp!+ ; immediate

: sq dup * ;

( Push a space. )
: bl 32 ;

( Conditionals. )
: push_bze ( Push &bze onto the stack. ) literal bze ;
: push_branch ( Push &branch onto the stack. ) literal branch ;

( Note how IF and THEN save and restore the rstack.  They must do this
  because the very act of entering them pushes a value on the
  rstack -- a value which will be popped when IF or THEN is finished
  executing -- so we need to work "underneath" that value. 
  [See doc/design for discussion of conditionals.] )

: if r> push_bze dp!+ here >r dp+ >r ; immediate

( THEN means ENDIF in this bizarre language. )
: then r> here r> ! dp+ >r ; immediate

( ELSE )
: else r> push_branch dp!+ here r> ! here >r dp+ >r ; immediate

( STRING: take the delimiter, compile the string into the
  dictionary.  This definition stolen from page 252 of Brodie.)
( c -- )
( : string word c@ 1 + allot ; )