\ a few forth examples.
\ to load into bashforth, do:
\ include demo.f
\ these require bashforth 0.37a, because of the
\ recent addition of ?do, used in some examples


\ -------------- example 1 --------------

\ standard beginner example:
: star  42 emit  ;
: stars  0 ?do star loop  ;
10 stars

\ -------------- example 2 --------------

\ catching errors:
: new  ( -- ) 
   cr ." starting a new interpreter"
   prompt
   ['] quit catch
   ?dup if
       cr ." interpreter aborted with error:"
       throw
   then  ;
\ execute  "new" to start new interpreter,
\ then cause an error, for example, by trying
\ to execute a non-existing word

\ -------------- example 3 --------------

\ beginners example again, using create> does
\ a word, creating words which emit characters
: emits ( c -- )
   create ,
   does> @ emit  ;

\ a word, creating words which can execute a word n times
: plural ( a -- )
   create ,
   does> @ swap
   0 ?do 
      dup >r execute r>
   loop drop  ;

\ -- using the above two words --
46 emits dot
' dot plural dots

5 dots


\ -------------- example 4 --------------

\ -- using create does> to build new datatype: array --

: array ( n -- )
   create allot
   does> +  ;


\ -- putting arrays to use --
: inc ( a -- )     dup @ 1+ swap !  ;

variable #contacts
: contact ( -- )
  #contacts @ constant
  #contacts inc ;   

contact alf
contact ben
contact carl
contact dee

#contacts @ array age   \ define array with name age, #contacts elements

25 carl age !
28 alf age !
22 dee age !
32 ben !

.( alf's age: )  alf age @ .