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|
\ tag: forth interpreter
\
\ Copyright (C) 2003 Stefan Reinauer
\
\ See the file "COPYING" for further information about
\ the copyright and warranty status of this work.
\
\
\ 7.3.4.6 Display pause
\
0 value interactive?
0 value terminate?
: exit?
interactive? 0= if
false exit
then
false \ FIXME we should check whether to interrupt output
\ and ask the user how to proceed.
;
\
\ 7.3.9.1 Defining words
\
: forget
s" This word is obsolescent." type cr
['] ' execute
cell - dup
@ dup
last ! latest !
here!
;
\
\ 7.3.9.2.4 Miscellaneous dictionary
\
\ interpreter. This word checks whether the interpreted word
\ is a word in dictionary or a number. It honours compile mode
\ and immediate/compile-only words.
: interpret
0 >in !
begin
parse-word dup 0> \ was there a word at all?
while
$find
if
dup flags? 0<> state @ 0= or if
execute
else
, \ compile mode && !immediate
then
else \ word is not known. maybe it's a number
2dup $number
if
span @ >in ! \ if we encountered an error, don't continue parsing
type 3a emit
-13 throw
else
-rot 2drop 1 handle-lit
then
then
depth 200 >= if -3 throw then
depth 0< if -4 throw then
rdepth 200 >= if -5 throw then
rdepth 0< if -6 throw then
repeat
2drop
;
: refill ( -- )
ib #ib @ expect 0 >in ! ;
: print-status ( exception -- )
space
?dup if
dup sys-debug \ system debug hook
case
-1 of s" Aborted." type endof
-2 of s" Aborted." type endof
-3 of s" Stack Overflow." type 0 depth! endof
-4 of s" Stack Underflow." type 0 depth! endof
-5 of s" Return Stack Overflow." type endof
-6 of s" Return Stack Underflow." type endof
-13 of s" undefined word." type endof
-15 of s" out of memory." type endof
-21 of s" undefined method." type endof
-22 of s" no such device." type endof
dup s" Exception #" type .
0 state !
endcase
else
state @ 0= if
s" ok"
else
s" compiled"
then
type
then
cr
;
defer status
['] noop ['] status (to)
: print-prompt
status
depth . 3e emit space
;
defer outer-interpreter
:noname
cr
begin
print-prompt
source 0 fill \ clean input buffer
refill
['] interpret catch print-status
terminate?
until
; ['] outer-interpreter (to)
\
\ 7.3.8.5 Other control flow commands
\
: save-source ( -- )
r> \ fetch our caller
ib >r #ib @ >r \ save current input buffer
source-id >r \ and all variables
span @ >r \ associated with it.
>in @ >r
>r \ move back our caller
;
: restore-source ( -- )
r>
r> >in !
r> span !
r> ['] source-id (to)
r> #ib !
r> ['] ib (to)
>r
;
: (evaluate) ( str len -- ??? )
save-source
-1 ['] source-id (to)
dup
#ib ! span !
['] ib (to)
interpret
restore-source
;
: evaluate ( str len -- ?? )
2dup + -rot
over + over do
i c@ 0a = if
i over -
(evaluate)
i 1+
then
loop
swap over - (evaluate)
;
: eval evaluate ;
|
