diff options
| -rw-r--r-- | edit.mu | 46 |
1 files changed, 37 insertions, 9 deletions
diff --git a/edit.mu b/edit.mu index 93a47bc6..6ff18546 100644 --- a/edit.mu +++ b/edit.mu @@ -1034,18 +1034,40 @@ recipe delete-before-cursor [ local-scope editor:address:editor-data <- next-ingredient before-cursor:address:address:duplex-list <- get-address *editor, before-cursor:offset - d:address:duplex-list <- get *editor, data:offset - # unless already at start - at-start?:boolean <- equal *before-cursor, d - reply-if at-start? - # delete character + # if at start of text (before-cursor at § sentinel), return prev:address:duplex-list <- prev-duplex *before-cursor + reply-unless prev + # save previous character, then delete it + previous-character:character <- get **before-cursor, value:offset remove-duplex *before-cursor - # update cursor *before-cursor <- copy prev + # update cursor coordinates + cursor-row:address:number <- get-address *editor, cursor-row:offset cursor-column:address:number <- get-address *editor, cursor-column:offset - *cursor-column <- subtract *cursor-column, 1 -#? $print [delete-before-cursor: ], *cursor-column, 10/newline + # 1. if not at left margin, move one character left + { + at-left-margin?:boolean <- equal *cursor-column, 0 + break-if at-left-margin? + *cursor-column <- subtract *cursor-column, 1 + reply + } + # 2. if at left margin, we must move to previous row: + assert *cursor-row, [unimplemented: moving cursor above top of screen] + *cursor-row <- subtract *cursor-row, 1 + { + # 2a. if previous character was newline, figure out how long the previous line is + previous-character-is-newline?:boolean <- equal previous-character, 10/newline + break-unless previous-character-is-newline? + # compute length of previous line + d:address:duplex-list <- get *editor, data:offset + end-of-line:number <- previous-line-length *before-cursor, d + # fudge factor: we're already at the last character, so we didn't count it + *cursor-column <- add end-of-line, 1 + reply + } + # 2b. if previous-character was not newline, we're just at a wrapped line + right:number <- get *editor, right:offset + *cursor-column <- subtract right, 1 # leave room for wrap icon ] # takes a pointer 'curr' into the doubly-linked list and its sentinel, counts @@ -1760,7 +1782,7 @@ scenario editor-clears-last-line-on-backspace [ # just one character in final line 1:address:array:character <- new [ab cd] - 2:address:editor-data <- new-editor 1:address:array:character, screen:address, 0/left, 5/right + 2:address:editor-data <- new-editor 1:address:array:character, screen:address, 0/left, 10/right assume-console [ left-click 2, 0 # cursor at only character in final line type [«] @@ -1769,12 +1791,18 @@ cd] replace-in-console 171/«, 3:event/backspace run [ editor-event-loop screen:address, console:address, 2:address:editor-data + 4:number <- get *2:address:editor-data, cursor-row:offset + 5:number <- get *2:address:editor-data, cursor-column:offset ] screen-should-contain [ . . .abcd . . . ] + memory-should-contain [ + 4 <- 1 + 5 <- 2 + ] ] scenario editor-inserts-two-spaces-on-tab [ |