| 1 | \ SAVE-INPUT and RESTORE-INPUT |
| 2 | |
| 3 | anew task-save-input.fth |
| 4 | |
| 5 | private{ |
| 6 | |
| 7 | : save-buffer ( -- column source-id 2 ) >in @ source-id 2 ; |
| 8 | |
| 9 | : restore-column ( column -- flag ) |
| 10 | source nip over < |
| 11 | IF drop true |
| 12 | ELSE >in ! false |
| 13 | THEN |
| 14 | ; |
| 15 | |
| 16 | \ Return the file-position of the beginning of the current line in |
| 17 | \ file SOURCE-ID. Assume that the current line is stored in SOURCE |
| 18 | \ and that the current file-position is at an end-of-line (or |
| 19 | \ end-of-file). |
| 20 | : line-start-position ( -- ud ) |
| 21 | source-id file-position throw |
| 22 | \ unless at end-of-file, subtract newline |
| 23 | source-id file-size throw 2over d= 0= IF 1 s>d d- THEN |
| 24 | \ subtract line length |
| 25 | source nip s>d d- |
| 26 | ; |
| 27 | |
| 28 | : save-file ( column line filepos:ud source-id 5 -- ) |
| 29 | >in @ |
| 30 | source-line-number@ |
| 31 | line-start-position |
| 32 | source-id |
| 33 | 5 |
| 34 | ; |
| 35 | |
| 36 | : restore-file ( column line filepos:ud -- flag ) |
| 37 | source-id reposition-file IF 2drop true exit THEN |
| 38 | refill 0= IF 2drop true exit THEN |
| 39 | source-line-number! |
| 40 | restore-column |
| 41 | ; |
| 42 | |
| 43 | : ndrop ( n*x n -- ) 0 ?do drop loop ; |
| 44 | |
| 45 | }private |
| 46 | |
| 47 | \ Source Stack |
| 48 | \ EVALUATE >IN SourceID=(-1) 2 |
| 49 | \ keyboard >IN SourceID=(0) 2 |
| 50 | \ file >IN lineNumber filePos SourceID=(fileID) 5 |
| 51 | : SAVE-INPUT ( -- column {line filepos}? source-id n ) |
| 52 | source-id case |
| 53 | -1 of save-buffer endof |
| 54 | 0 of save-buffer endof |
| 55 | drop save-file exit |
| 56 | endcase |
| 57 | ; |
| 58 | |
| 59 | : RESTORE-INPUT ( column {line filepos}? source-id n -- flag ) |
| 60 | over source-id <> IF ndrop true exit THEN |
| 61 | drop |
| 62 | case |
| 63 | -1 of restore-column endof |
| 64 | 0 of restore-column endof |
| 65 | drop restore-file exit |
| 66 | endcase |
| 67 | ; |
| 68 | |
| 69 | privatize |