\ SAVE-INPUT and RESTORE-INPUT
\ This code is part of pForth.
\ Permission to use, copy, modify, and/or distribute this
\ software for any purpose with or without fee is hereby granted.
\ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
\ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
\ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
\ THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
\ CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
\ FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
\ CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
\ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
: SAVE-BUFFER ( -- column source-id 2 ) >in @ source-id 2 ;
\ Restore >IN from COLUMN unless COLUMN is too large. Valid values
\ for COLUMN are from 0 to (including) the length of SOURCE plus one.
: RESTORE-COLUMN ( column -- flag )
\ Return the file-position of the beginning of the current line in
\ file SOURCE-ID. Assume that the current line is stored in SOURCE
\ and that the current file-position is at an end-of-line (or
: LINE-START-POSITION ( -- ud )
source-id file-position throw
\ unless at end-of-file, subtract newline
source-id file-size throw 2over d= 0= IF 1 s>d d- THEN
: SAVE-FILE ( column line filepos:ud source-id 5 -- )
: RESTORE-FILE ( column line filepos:ud -- flag )
source-id reposition-file IF 2drop true EXIT THEN
refill 0= IF 2drop true EXIT THEN
: NDROP ( n*x n -- ) 0 ?DO drop LOOP ;
\ EVALUATE >IN SourceID=(-1) 2
\ keyboard >IN SourceID=(0) 2
\ file >IN lineNumber filePos SourceID=(fileID) 5
: SAVE-INPUT ( -- column {line filepos}? source-id n )
: RESTORE-INPUT ( column {line filepos}? source-id n -- flag )
over source-id <> IF ndrop true EXIT THEN
-1 OF restore-column ENDOF
0 OF restore-column ENDOF