## special shortcuts for manipulating the editor
# Some keys on the keyboard generate unicode characters, others generate
# terminfo key codes. We need to modify different places in the two cases.
# tab - insert two spaces
scenario editor-inserts-two-spaces-on-tab [
assume-screen 10/width, 5/height
# 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:screen, 0/left, 5/right
assume-console [
press tab
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
. ab .
.cd .
]
]
after <handle-special-character> [
{
tab?:boolean <- equal c, 9/tab
break-unless tab?
<insert-character-begin>
editor, screen, go-render?:boolean <- insert-at-cursor editor, 32/space, screen
editor, screen, go-render?:boolean <- insert-at-cursor editor, 32/space, screen
<insert-character-end>
go-render? <- copy 1/true
return
}
]
# backspace - delete character before cursor
scenario editor-handles-backspace-key [
assume-screen 10/width, 5/height
1:address:array:character <- new [abc]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
assume-console [
left-click 1, 1
press backspace
]
run [
editor-event-loop screen:address:screen, console:address:console, 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 [
. .
.bc .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
memory-should-contain [
4 <- 1
5 <- 0
]
check-trace-count-for-label 3, [print-character] # length of original line to overwrite
]
after <handle-special-character> [
{
delete-previous-character?:boolean <- equal c, 8/backspace
break-unless delete-previous-character?
<backspace-character-begin>
editor, screen, go-render?:boolean, backspaced-cell:address:duplex-list:character <- delete-before-cursor editor, screen
<backspace-character-end>
return
}
]
# return values:
# go-render? - whether caller needs to update the screen
# backspaced-cell - value deleted (or 0 if nothing was deleted) so we can save it for undo, etc.
def delete-before-cursor editor:address:editor-data, screen:address:screen -> editor:address:editor-data, screen:address:screen, go-render?:boolean, backspaced-cell:address:duplex-list:character [
local-scope
load-ingredients
before-cursor:address:duplex-list:character <- get *editor, before-cursor:offset
data:address:duplex-list:character <- get *editor, data:offset
# if at start of text (before-cursor at § sentinel), return
prev:address:duplex-list:character <- prev before-cursor
go-render?, backspaced-cell <- copy 0/no-more-render, 0/nothing-deleted
return-unless prev
go-render? <- copy 1/true
trace 10, [app], [delete-before-cursor]
original-row:number <- get *editor, cursor-row:offset
editor <- move-cursor-coordinates-left editor
backspaced-cell:address:duplex-list:character <- copy before-cursor
data <- remove before-cursor, data # will also neatly trim next/prev pointers in backspaced-cell/before-cursor
before-cursor <- copy prev
*editor <- put *editor, before-cursor:offset, before-cursor
screen-width:number <- screen-width screen
cursor-row:number <- get *editor, cursor-row:offset
cursor-column:number <- get *editor, cursor-column:offset
# did we just backspace over a newline?
same-row?:boolean <- equal cursor-row, original-row
return-unless same-row?
left:number <- get *editor, left:offset
right:number <- get *editor, right:offset
curr:address:duplex-list:character <- next before-cursor
screen <- move-cursor screen, cursor-row, cursor-column
curr-column:number <- copy cursor-column
{
# hit right margin? give up and let caller render
at-right?:boolean <- greater-or-equal curr-column, right
return-if at-right?
break-unless curr
# newline? done.
currc:character <- get *curr, value:offset
at-newline?:boolean <- equal currc, 10/newline
break-if at-newline?
screen <- print screen, currc
curr-column <- add curr-column, 1
curr <- next curr
loop
}
# we're guaranteed not to be at the right margin
space:character <- copy 32/space
screen <- print screen, space
go-render? <- copy 0/false
]
def move-cursor-coordinates-left editor:address:editor-data -> editor:address:editor-data [
local-scope
load-ingredients
before-cursor:address:duplex-list:character <- get *editor, before-cursor:offset
cursor-row:number <- get *editor, cursor-row:offset
cursor-column:number <- get *editor, cursor-column:offset
left:number <- get *editor, left:offset
# if not at left margin, move one character left
{
at-left-margin?:boolean <- equal cursor-column, left
break-if at-left-margin?
trace 10, [app], [decrementing cursor column]
cursor-column <- subtract cursor-column, 1
*editor <- put *editor, cursor-column:offset, cursor-column
return
}
# if at left margin, we must move to previous row:
top-of-screen?:boolean <- equal cursor-row, 1 # exclude menu bar
{
break-if top-of-screen?
cursor-row <- subtract cursor-row, 1
*editor <- put *editor, cursor-row:offset, cursor-row
}
{
break-unless top-of-screen?
# no scroll, so do nothing
}
{
# case 1: if previous character was newline, figure out how long the previous line is
previous-character:character <- get *before-cursor, value:offset
previous-character-is-newline?:boolean <- equal previous-character, 10/newline
break-unless previous-character-is-newline?
# compute length of previous line
trace 10, [app], [switching to previous line]
d:address:duplex-list:character <- get *editor, data:offset
end-of-line:number <- previous-line-length before-cursor, d
right:number <- get *editor, right:offset
width:number <- subtract right, left
wrap?:boolean <- greater-than end-of-line, width
{
break-unless wrap?
_, column-offset:number <- divide-with-remainder end-of-line, width
cursor-column <- add left, column-offset
*editor <- put *editor, cursor-column:offset, cursor-column
}
{
break-if wrap?
cursor-column <- add left, end-of-line
*editor <- put *editor, cursor-column:offset, cursor-column
}
return
}
# case 2: if previous-character was not newline, we're just at a wrapped line
trace 10, [app], [wrapping to previous line]
right:number <- get *editor, right:offset
cursor-column <- subtract right, 1 # leave room for wrap icon
*editor <- put *editor, cursor-column:offset, cursor-column
]
# takes a pointer 'curr' into the doubly-linked list and its sentinel, counts
# the length of the previous line before the 'curr' pointer.
def previous-line-length curr:address:duplex-list:character, start:address:duplex-list:character -> result:number [
local-scope
load-ingredients
result:number <- copy 0
return-unless curr
at-start?:boolean <- equal curr, start
return-if at-start?
{
curr <- prev curr
break-unless curr
at-start?:boolean <- equal curr, start
break-if at-start?
c:character <- get *curr, value:offset
at-newline?:boolean <- equal c, 10/newline
break-if at-newline?
result <- add result, 1
loop
}
]
scenario editor-clears-last-line-on-backspace [
assume-screen 10/width, 5/height
# 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:screen, 0/left, 10/right
assume-console [
left-click 2, 0 # cursor at only character in final line
press backspace
]
run [
editor-event-loop screen:address:screen, console:address:console, 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-joins-and-wraps-lines-on-backspace [
assume-screen 10/width, 5/height
# initialize editor with two long-ish but non-wrapping lines
1:address:array:character <- new [abc def
ghi jkl]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# position the cursor at the start of the second and hit backspace
assume-console [
left-click 2, 0
press backspace
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
# resulting single line should wrap correctly
screen-should-contain [
. .
.abc defgh↩.
.i jkl .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
scenario editor-wraps-long-lines-on-backspace [
assume-screen 10/width, 5/height
# initialize editor in part of the screen with a long line
1:address:array:character <- new [abc def ghij]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 8/right
editor-render screen, 2:address:editor-data
# confirm that it wraps
screen-should-contain [
. .
.abc def↩ .
. ghij .
.┈┈┈┈┈┈┈┈ .
]
$clear-trace
# position the cursor somewhere in the middle of the top screen line and hit backspace
assume-console [
left-click 1, 4
press backspace
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
# resulting single line should wrap correctly and not overflow its bounds
screen-should-contain [
. .
.abcdef ↩ .
.ghij .
.┈┈┈┈┈┈┈┈ .
. .
]
]
# delete - delete character at cursor
scenario editor-handles-delete-key [
assume-screen 10/width, 5/height
1:address:array:character <- new [abc]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
assume-console [
press delete
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
.bc .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
check-trace-count-for-label 3, [print-character] # length of original line to overwrite
$clear-trace
assume-console [
press delete
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
.c .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
check-trace-count-for-label 2, [print-character] # new length to overwrite
]
after <handle-special-key> [
{
delete-next-character?:boolean <- equal k, 65522/delete
break-unless delete-next-character?
<delete-character-begin>
editor, screen, go-render?:boolean, deleted-cell:address:duplex-list:character <- delete-at-cursor editor, screen
<delete-character-end>
return
}
]
def delete-at-cursor editor:address:editor-data, screen:address:screen -> editor:address:editor-data, screen:address:screen, go-render?:boolean, deleted-cell:address:duplex-list:character [
local-scope
load-ingredients
before-cursor:address:duplex-list:character <- get *editor, before-cursor:offset
data:address:duplex-list:character <- get *editor, data:offset
deleted-cell:address:duplex-list:character <- next before-cursor
go-render? <- copy 0/false
return-unless deleted-cell
currc:character <- get *deleted-cell, value:offset
data <- remove deleted-cell, data
deleted-newline?:boolean <- equal currc, 10/newline
go-render? <- copy 1/true
return-if deleted-newline?
# wasn't a newline? render rest of line
curr:address:duplex-list:character <- next before-cursor # refresh after remove above
cursor-row:number <- get *editor, cursor-row:offset
cursor-column:number <- get *editor, cursor-column:offset
screen <- move-cursor screen, cursor-row, cursor-column
curr-column:number <- copy cursor-column
screen-width:number <- screen-width screen
{
# hit right margin? give up and let caller render
at-right?:boolean <- greater-or-equal curr-column, screen-width
go-render? <- copy 1/true
return-if at-right?
break-unless curr
# newline? done.
currc:character <- get *curr, value:offset
at-newline?:boolean <- equal currc, 10/newline
break-if at-newline?
screen <- print screen, currc
curr-column <- add curr-column, 1
curr <- next curr
loop
}
# we're guaranteed not to be at the right margin
space:character <- copy 32/space
screen <- print screen, space
go-render? <- copy 0/false
]
# right arrow
scenario editor-moves-cursor-right-with-key [
assume-screen 10/width, 5/height
1:address:array:character <- new [abc]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
assume-console [
press right-arrow
type [0]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
.a0bc .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
check-trace-count-for-label 3, [print-character] # 0 and following characters
]
after <handle-special-key> [
{
move-to-next-character?:boolean <- equal k, 65514/right-arrow
break-unless move-to-next-character?
# if not at end of text
next-cursor:address:duplex-list:character <- next before-cursor
break-unless next-cursor
# scan to next character
<move-cursor-begin>
before-cursor <- copy next-cursor
*editor <- put *editor, before-cursor:offset, before-cursor
editor, go-render?:boolean <- move-cursor-coordinates-right editor, screen-height
screen <- move-cursor screen, cursor-row, cursor-column
undo-coalesce-tag:number <- copy 2/right-arrow
<move-cursor-end>
return
}
]
def move-cursor-coordinates-right editor:address:editor-data, screen-height:number -> editor:address:editor-data, go-render?:boolean [
local-scope
load-ingredients
before-cursor:address:duplex-list:character <- get *editor before-cursor:offset
cursor-row:number <- get *editor, cursor-row:offset
cursor-column:number <- get *editor, cursor-column:offset
left:number <- get *editor, left:offset
right:number <- get *editor, right:offset
# if crossed a newline, move cursor to start of next row
{
old-cursor-character:character <- get *before-cursor, value:offset
was-at-newline?:boolean <- equal old-cursor-character, 10/newline
break-unless was-at-newline?
cursor-row <- add cursor-row, 1
*editor <- put *editor, cursor-row:offset, cursor-row
cursor-column <- copy left
*editor <- put *editor, cursor-column:offset, cursor-column
below-screen?:boolean <- greater-or-equal cursor-row, screen-height # must be equal
go-render? <- copy 0/false
return-unless below-screen?
cursor-row <- subtract cursor-row, 1 # bring back into screen range
*editor <- put *editor, cursor-row:offset, cursor-row
go-render? <- copy 1/true
return
}
# if the line wraps, move cursor to start of next row
{
# if we're at the column just before the wrap indicator
wrap-column:number <- subtract right, 1
at-wrap?:boolean <- equal cursor-column, wrap-column
break-unless at-wrap?
# and if next character isn't newline
next:address:duplex-list:character <- next before-cursor
break-unless next
next-character:character <- get *next, value:offset
newline?:boolean <- equal next-character, 10/newline
break-if newline?
cursor-row <- add cursor-row, 1
*editor <- put *editor, cursor-row:offset, cursor-row
cursor-column <- copy left
*editor <- put *editor, cursor-column:offset, cursor-column
below-screen?:boolean <- greater-or-equal cursor-row, screen-height # must be equal
return-unless below-screen?, editor/same-as-ingredient:0, 0/no-more-render
cursor-row <- subtract cursor-row, 1 # bring back into screen range
*editor <- put *editor, cursor-row:offset, cursor-row
go-render? <- copy 1/true
return
}
# otherwise move cursor one character right
cursor-column <- add cursor-column, 1
*editor <- put *editor, cursor-column:offset, cursor-column
go-render? <- copy 0/false
]
scenario editor-moves-cursor-to-next-line-with-right-arrow [
assume-screen 10/width, 5/height
1:address:array:character <- new [abc
d]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# type right-arrow a few times to get to start of second line
assume-console [
press right-arrow
press right-arrow
press right-arrow
press right-arrow # next line
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
check-trace-count-for-label 0, [print-character]
# type something and ensure it goes where it should
assume-console [
type [0]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
.abc .
.0d .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
check-trace-count-for-label 2, [print-character] # new length of second line
]
scenario editor-moves-cursor-to-next-line-with-right-arrow-2 [
assume-screen 10/width, 5/height
1:address:array:character <- new [abc
d]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 1/left, 10/right
editor-render screen, 2:address:editor-data
assume-console [
press right-arrow
press right-arrow
press right-arrow
press right-arrow # next line
type [0]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
. abc .
. 0d .
. ┈┈┈┈┈┈┈┈┈.
. .
]
]
scenario editor-moves-cursor-to-next-wrapped-line-with-right-arrow [
assume-screen 10/width, 5/height
1:address:array:character <- new [abcdef]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 5/right
editor-render screen, 2:address:editor-data
$clear-trace
assume-console [
left-click 1, 3
press right-arrow
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
screen-should-contain [
. .
.abcd↩ .
.ef .
.┈┈┈┈┈ .
. .
]
memory-should-contain [
3 <- 2
4 <- 0
]
check-trace-count-for-label 0, [print-character]
]
scenario editor-moves-cursor-to-next-wrapped-line-with-right-arrow-2 [
assume-screen 10/width, 5/height
# line just barely wrapping
1:address:array:character <- new [abcde]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 5/right
editor-render screen, 2:address:editor-data
$clear-trace
# position cursor at last character before wrap and hit right-arrow
assume-console [
left-click 1, 3
press right-arrow
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
memory-should-contain [
3 <- 2
4 <- 0
]
# now hit right arrow again
assume-console [
press right-arrow
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
memory-should-contain [
3 <- 2
4 <- 1
]
check-trace-count-for-label 0, [print-character]
]
scenario editor-moves-cursor-to-next-wrapped-line-with-right-arrow-3 [
assume-screen 10/width, 5/height
1:address:array:character <- new [abcdef]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 1/left, 6/right
editor-render screen, 2:address:editor-data
$clear-trace
assume-console [
left-click 1, 4
press right-arrow
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
screen-should-contain [
. .
. abcd↩ .
. ef .
. ┈┈┈┈┈ .
. .
]
memory-should-contain [
3 <- 2
4 <- 1
]
check-trace-count-for-label 0, [print-character]
]
scenario editor-moves-cursor-to-next-line-with-right-arrow-at-end-of-line [
assume-screen 10/width, 5/height
1:address:array:character <- new [abc
d]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# move to end of line, press right-arrow, type a character
assume-console [
left-click 1, 3
press right-arrow
type [0]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
# new character should be in next line
screen-should-contain [
. .
.abc .
.0d .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
check-trace-count-for-label 2, [print-character]
]
# todo: ctrl-right: next word-end
# left arrow
scenario editor-moves-cursor-left-with-key [
assume-screen 10/width, 5/height
1:address:array:character <- new [abc]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
assume-console [
left-click 1, 2
press left-arrow
type [0]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
.a0bc .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
check-trace-count-for-label 3, [print-character]
]
after <handle-special-key> [
{
move-to-previous-character?:boolean <- equal k, 65515/left-arrow
break-unless move-to-previous-character?
trace 10, [app], [left arrow]
# if not at start of text (before-cursor at § sentinel)
prev:address:duplex-list:character <- prev before-cursor
go-render? <- copy 0/false
return-unless prev
<move-cursor-begin>
editor <- move-cursor-coordinates-left editor
before-cursor <- copy prev
*editor <- put *editor, before-cursor:offset, before-cursor
undo-coalesce-tag:number <- copy 1/left-arrow
<move-cursor-end>
return
}
]
scenario editor-moves-cursor-to-previous-line-with-left-arrow-at-start-of-line [
assume-screen 10/width, 5/height
# initialize editor with two lines
1:address:array:character <- new [abc
d]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# position cursor at start of second line (so there's no previous newline)
assume-console [
left-click 2, 0
press left-arrow
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
memory-should-contain [
3 <- 1
4 <- 3
]
check-trace-count-for-label 0, [print-character]
]
scenario editor-moves-cursor-to-previous-line-with-left-arrow-at-start-of-line-2 [
assume-screen 10/width, 5/height
# initialize editor with three lines
1:address:array:character <- new [abc
def
g]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# position cursor further down (so there's a newline before the character at
# the cursor)
assume-console [
left-click 3, 0
press left-arrow
type [0]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
.abc .
.def0 .
.g .
.┈┈┈┈┈┈┈┈┈┈.
]
check-trace-count-for-label 1, [print-character] # just the '0'
]
scenario editor-moves-cursor-to-previous-line-with-left-arrow-at-start-of-line-3 [
assume-screen 10/width, 5/height
1:address:array:character <- new [abc
def
g]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# position cursor at start of text, press left-arrow, then type a character
assume-console [
left-click 1, 0
press left-arrow
type [0]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
# left-arrow should have had no effect
screen-should-contain [
. .
.0abc .
.def .
.g .
.┈┈┈┈┈┈┈┈┈┈.
]
check-trace-count-for-label 4, [print-character] # length of first line
]
scenario editor-moves-cursor-to-previous-line-with-left-arrow-at-start-of-line-4 [
assume-screen 10/width, 5/height
# initialize editor with text containing an empty line
1:address:array:character <- new [abc
d]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# position cursor right after empty line
assume-console [
left-click 3, 0
press left-arrow
type [0]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
.abc .
.0 .
.d .
.┈┈┈┈┈┈┈┈┈┈.
]
check-trace-count-for-label 1, [print-character] # just the '0'
]
scenario editor-moves-across-screen-lines-across-wrap-with-left-arrow [
assume-screen 10/width, 5/height
# initialize editor with a wrapping line
1:address:array:character <- new [abcdef]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 5/right
editor-render screen, 2:address:editor-data
$clear-trace
screen-should-contain [
. .
.abcd↩ .
.ef .
.┈┈┈┈┈ .
. .
]
# position cursor right after empty line
assume-console [
left-click 2, 0
press left-arrow
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
memory-should-contain [
3 <- 1 # previous row
4 <- 3 # right margin except wrap icon
]
check-trace-count-for-label 0, [print-character]
]
scenario editor-moves-across-screen-lines-to-wrapping-line-with-left-arrow [
assume-screen 10/width, 5/height
# initialize editor with a wrapping line followed by a second line
1:address:array:character <- new [abcdef
g]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 5/right
editor-render screen, 2:address:editor-data
$clear-trace
screen-should-contain [
. .
.abcd↩ .
.ef .
.g .
.┈┈┈┈┈ .
]
# position cursor right after empty line
assume-console [
left-click 3, 0
press left-arrow
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
memory-should-contain [
3 <- 2 # previous row
4 <- 2 # end of wrapped line
]
check-trace-count-for-label 0, [print-character]
]
scenario editor-moves-across-screen-lines-to-non-wrapping-line-with-left-arrow [
assume-screen 10/width, 5/height
# initialize editor with a line on the verge of wrapping, followed by a second line
1:address:array:character <- new [abcd
e]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 5/right
editor-render screen, 2:address:editor-data
$clear-trace
screen-should-contain [
. .
.abcd .
.e .
.┈┈┈┈┈ .
. .
]
# position cursor right after empty line
assume-console [
left-click 2, 0
press left-arrow
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
memory-should-contain [
3 <- 1 # previous row
4 <- 4 # end of wrapped line
]
check-trace-count-for-label 0, [print-character]
]
# todo: ctrl-left: previous word-start
# up arrow
scenario editor-moves-to-previous-line-with-up-arrow [
assume-screen 10/width, 5/height
1:address:array:character <- new [abc
def]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
assume-console [
left-click 2, 1
press up-arrow
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
memory-should-contain [
3 <- 1
4 <- 1
]
check-trace-count-for-label 0, [print-character]
assume-console [
type [0]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
.a0bc .
.def .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
after <handle-special-key> [
{
move-to-previous-line?:boolean <- equal k, 65517/up-arrow
break-unless move-to-previous-line?
<move-cursor-begin>
editor, go-render? <- move-to-previous-line editor
undo-coalesce-tag:number <- copy 3/up-arrow
<move-cursor-end>
return
}
]
def move-to-previous-line editor:address:editor-data -> editor:address:editor-data, go-render?:boolean [
local-scope
load-ingredients
cursor-row:number <- get *editor, cursor-row:offset
cursor-column:number <- get *editor, cursor-column:offset
before-cursor:address:duplex-list:character <- get *editor, before-cursor:offset
left:number <- get *editor, left:offset
right:number <- get *editor, right:offset
already-at-top?:boolean <- lesser-or-equal cursor-row, 1/top
{
# if cursor not at top, move it
break-if already-at-top?
# if not at newline, move to start of line (previous newline)
# then scan back another line
# if either step fails, give up without modifying cursor or coordinates
curr:address:duplex-list:character <- copy before-cursor
{
old:address:duplex-list:character <- copy curr
c2:character <- get *curr, value:offset
at-newline?:boolean <- equal c2, 10/newline
break-if at-newline?
curr:address:duplex-list:character <- before-previous-line curr, editor
no-motion?:boolean <- equal curr, old
go-render? <- copy 0/false
return-if no-motion?
}
{
old <- copy curr
curr <- before-previous-line curr, editor
no-motion?:boolean <- equal curr, old
go-render? <- copy 0/false
return-if no-motion?
}
before-cursor <- copy curr
*editor <- put *editor, before-cursor:offset, before-cursor
cursor-row <- subtract cursor-row, 1
*editor <- put *editor, cursor-row:offset, cursor-row
# scan ahead to right column or until end of line
target-column:number <- copy cursor-column
cursor-column <- copy left
*editor <- put *editor, cursor-column:offset, cursor-column
{
done?:boolean <- greater-or-equal cursor-column, target-column
break-if done?
curr:address:duplex-list:character <- next before-cursor
break-unless curr
currc:character <- get *curr, value:offset
at-newline?:boolean <- equal currc, 10/newline
break-if at-newline?
#
before-cursor <- copy curr
*editor <- put *editor, before-cursor:offset, before-cursor
cursor-column <- add cursor-column, 1
*editor <- put *editor, cursor-column:offset, cursor-column
loop
}
go-render? <- copy 0/false
return
}
{
# if cursor already at top, do nothing
break-unless already-at-top?
go-render? <- copy 0/true
return
}
]
scenario editor-adjusts-column-at-previous-line [
assume-screen 10/width, 5/height
1:address:array:character <- new [ab
def]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
assume-console [
left-click 2, 3
press up-arrow
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
memory-should-contain [
3 <- 1
4 <- 2
]
check-trace-count-for-label 0, [print-character]
assume-console [
type [0]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
.ab0 .
.def .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
scenario editor-adjusts-column-at-empty-line [
assume-screen 10/width, 5/height
1:address:array:character <- new [
def]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
assume-console [
left-click 2, 3
press up-arrow
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
memory-should-contain [
3 <- 1
4 <- 0
]
check-trace-count-for-label 0, [print-character]
assume-console [
type [0]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
.0 .
.def .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
scenario editor-moves-to-previous-line-from-left-margin [
assume-screen 10/width, 5/height
# start out with three lines
1:address:array:character <- new [abc
def
ghi]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# click on the third line and hit up-arrow, so you end up just after a newline
assume-console [
left-click 3, 0
press up-arrow
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
memory-should-contain [
3 <- 2
4 <- 0
]
check-trace-count-for-label 0, [print-character]
assume-console [
type [0]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
.abc .
.0def .
.ghi .
.┈┈┈┈┈┈┈┈┈┈.
]
]
# down arrow
scenario editor-moves-to-next-line-with-down-arrow [
assume-screen 10/width, 5/height
1:address:array:character <- new [abc
def]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# cursor starts out at (1, 0)
assume-console [
press down-arrow
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
# ..and ends at (2, 0)
memory-should-contain [
3 <- 2
4 <- 0
]
check-trace-count-for-label 0, [print-character]
assume-console [
type [0]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
.abc .
.0def .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
after <handle-special-key> [
{
move-to-next-line?:boolean <- equal k, 65516/down-arrow
break-unless move-to-next-line?
<move-cursor-begin>
editor <- move-to-next-line editor, screen-height
undo-coalesce-tag:number <- copy 4/down-arrow
<move-cursor-end>
return
}
]
def move-to-next-line editor:address:editor-data, screen-height:number -> editor:address:editor-data [
local-scope
load-ingredients
cursor-row:number <- get *editor, cursor-row:offset
cursor-column:number <- get *editor, cursor-column:offset
before-cursor:address:duplex-list:character <- get *editor, before-cursor:offset
left:number <- get *editor, left:offset
right:number <- get *editor, right:offset
last-line:number <- subtract screen-height, 1
already-at-bottom?:boolean <- greater-or-equal cursor-row, last-line
# if cursor not at bottom
return-if already-at-bottom?
# scan to start of next line, then to right column or until end of line
max:number <- subtract right, left
next-line:address:duplex-list:character <- before-start-of-next-line before-cursor, max
# already at end of buffer? do nothing
no-motion?:boolean <- equal next-line, before-cursor
return-if no-motion?
cursor-row <- add cursor-row, 1
*editor <- put *editor, cursor-row:offset, cursor-row
before-cursor <- copy next-line
*editor <- put *editor, before-cursor:offset, before-cursor
target-column:number <- copy cursor-column
cursor-column <- copy left
*editor <- put *editor, cursor-column:offset, cursor-column
{
done?:boolean <- greater-or-equal cursor-column, target-column
break-if done?
curr:address:duplex-list:character <- next before-cursor
break-unless curr
currc:character <- get *curr, value:offset
at-newline?:boolean <- equal currc, 10/newline
break-if at-newline?
#
before-cursor <- copy curr
*editor <- put *editor, before-cursor:offset, before-cursor
cursor-column <- add cursor-column, 1
*editor <- put *editor, cursor-column:offset, cursor-column
loop
}
]
scenario editor-adjusts-column-at-next-line [
assume-screen 10/width, 5/height
1:address:array:character <- new [abc
de]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
assume-console [
left-click 1, 3
press down-arrow
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
memory-should-contain [
3 <- 2
4 <- 2
]
check-trace-count-for-label 0, [print-character]
assume-console [
type [0]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
screen-should-contain [
. .
.abc .
.de0 .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
# ctrl-a/home - move cursor to start of line
scenario editor-moves-to-start-of-line-with-ctrl-a [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# start on second line, press ctrl-a
assume-console [
left-click 2, 3
press ctrl-a
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
4:number <- get *2:address:editor-data, cursor-row:offset
5:number <- get *2:address:editor-data, cursor-column:offset
]
# cursor moves to start of line
memory-should-contain [
4 <- 2
5 <- 0
]
check-trace-count-for-label 0, [print-character]
]
after <handle-special-character> [
{
move-to-start-of-line?:boolean <- equal c, 1/ctrl-a
break-unless move-to-start-of-line?
<move-cursor-begin>
move-to-start-of-line editor
undo-coalesce-tag:number <- copy 0/never
<move-cursor-end>
go-render? <- copy 0/false
return
}
]
after <handle-special-key> [
{
move-to-start-of-line?:boolean <- equal k, 65521/home
break-unless move-to-start-of-line?
<move-cursor-begin>
move-to-start-of-line editor
undo-coalesce-tag:number <- copy 0/never
<move-cursor-end>
go-render? <- copy 0/false
return
}
]
def move-to-start-of-line editor:address:editor-data -> editor:address:editor-data [
local-scope
load-ingredients
# update cursor column
left:number <- get *editor, left:offset
cursor-column:number <- copy left
*editor <- put *editor, cursor-column:offset, cursor-column
# update before-cursor
before-cursor:address:duplex-list:character <- get *editor, before-cursor:offset
init:address:duplex-list:character <- get *editor, data:offset
# while not at start of line, move
{
at-start-of-text?:boolean <- equal before-cursor, init
break-if at-start-of-text?
prev:character <- get *before-cursor, value:offset
at-start-of-line?:boolean <- equal prev, 10/newline
break-if at-start-of-line?
before-cursor <- prev before-cursor
*editor <- put *editor, before-cursor:offset, before-cursor
assert before-cursor, [move-to-start-of-line tried to move before start of text]
loop
}
]
scenario editor-moves-to-start-of-line-with-ctrl-a-2 [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# start on first line (no newline before), press ctrl-a
assume-console [
left-click 1, 3
press ctrl-a
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
4:number <- get *2:address:editor-data, cursor-row:offset
5:number <- get *2:address:editor-data, cursor-column:offset
]
# cursor moves to start of line
memory-should-contain [
4 <- 1
5 <- 0
]
check-trace-count-for-label 0, [print-character]
]
scenario editor-moves-to-start-of-line-with-home [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
$clear-trace
# start on second line, press 'home'
assume-console [
left-click 2, 3
press home
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
# cursor moves to start of line
memory-should-contain [
3 <- 2
4 <- 0
]
check-trace-count-for-label 0, [print-character]
]
scenario editor-moves-to-start-of-line-with-home-2 [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# start on first line (no newline before), press 'home'
assume-console [
left-click 1, 3
press home
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
# cursor moves to start of line
memory-should-contain [
3 <- 1
4 <- 0
]
check-trace-count-for-label 0, [print-character]
]
# ctrl-e/end - move cursor to end of line
scenario editor-moves-to-end-of-line-with-ctrl-e [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# start on first line, press ctrl-e
assume-console [
left-click 1, 1
press ctrl-e
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
4:number <- get *2:address:editor-data, cursor-row:offset
5:number <- get *2:address:editor-data, cursor-column:offset
]
# cursor moves to end of line
memory-should-contain [
4 <- 1
5 <- 3
]
check-trace-count-for-label 0, [print-character]
# editor inserts future characters at cursor
assume-console [
type [z]
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
4:number <- get *2:address:editor-data, cursor-row:offset
5:number <- get *2:address:editor-data, cursor-column:offset
]
memory-should-contain [
4 <- 1
5 <- 4
]
screen-should-contain [
. .
.123z .
.456 .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
check-trace-count-for-label 1, [print-character]
]
after <handle-special-character> [
{
move-to-end-of-line?:boolean <- equal c, 5/ctrl-e
break-unless move-to-end-of-line?
<move-cursor-begin>
move-to-end-of-line editor
undo-coalesce-tag:number <- copy 0/never
<move-cursor-end>
go-render? <- copy 0/false
return
}
]
after <handle-special-key> [
{
move-to-end-of-line?:boolean <- equal k, 65520/end
break-unless move-to-end-of-line?
<move-cursor-begin>
move-to-end-of-line editor
undo-coalesce-tag:number <- copy 0/never
<move-cursor-end>
go-render? <- copy 0/false
return
}
]
def move-to-end-of-line editor:address:editor-data -> editor:address:editor-data [
local-scope
load-ingredients
before-cursor:address:duplex-list:character <- get *editor, before-cursor:offset
cursor-column:number <- get *editor, cursor-column:offset
# while not at start of line, move
{
next:address:duplex-list:character <- next before-cursor
break-unless next # end of text
nextc:character <- get *next, value:offset
at-end-of-line?:boolean <- equal nextc, 10/newline
break-if at-end-of-line?
before-cursor <- copy next
*editor <- put *editor, before-cursor:offset, before-cursor
cursor-column <- add cursor-column, 1
*editor <- put *editor, cursor-column:offset, cursor-column
loop
}
]
scenario editor-moves-to-end-of-line-with-ctrl-e-2 [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# start on second line (no newline after), press ctrl-e
assume-console [
left-click 2, 1
press ctrl-e
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
4:number <- get *2:address:editor-data, cursor-row:offset
5:number <- get *2:address:editor-data, cursor-column:offset
]
# cursor moves to end of line
memory-should-contain [
4 <- 2
5 <- 3
]
check-trace-count-for-label 0, [print-character]
]
scenario editor-moves-to-end-of-line-with-end [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# start on first line, press 'end'
assume-console [
left-click 1, 1
press end
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
# cursor moves to end of line
memory-should-contain [
3 <- 1
4 <- 3
]
check-trace-count-for-label 0, [print-character]
]
scenario editor-moves-to-end-of-line-with-end-2 [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
editor-render screen, 2:address:editor-data
$clear-trace
# start on second line (no newline after), press 'end'
assume-console [
left-click 2, 1
press end
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
3:number <- get *2:address:editor-data, cursor-row:offset
4:number <- get *2:address:editor-data, cursor-column:offset
]
# cursor moves to end of line
memory-should-contain [
3 <- 2
4 <- 3
]
check-trace-count-for-label 0, [print-character]
]
# ctrl-u - delete text from start of line until (but not at) cursor
scenario editor-deletes-to-start-of-line-with-ctrl-u [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
# start on second line, press ctrl-u
assume-console [
left-click 2, 2
press ctrl-u
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
# cursor deletes to start of line
screen-should-contain [
. .
.123 .
.6 .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
after <handle-special-character> [
{
delete-to-start-of-line?:boolean <- equal c, 21/ctrl-u
break-unless delete-to-start-of-line?
<delete-to-start-of-line-begin>
deleted-cells:address:duplex-list:character <- delete-to-start-of-line editor
<delete-to-start-of-line-end>
go-render? <- copy 1/true
return
}
]
def delete-to-start-of-line editor:address:editor-data -> result:address:duplex-list:character, editor:address:editor-data [
local-scope
load-ingredients
# compute range to delete
init:address:duplex-list:character <- get *editor, data:offset
before-cursor:address:duplex-list:character <- get *editor, before-cursor:offset
start:address:duplex-list:character <- copy before-cursor
end:address:duplex-list:character <- next before-cursor
{
at-start-of-text?:boolean <- equal start, init
break-if at-start-of-text?
curr:character <- get *start, value:offset
at-start-of-line?:boolean <- equal curr, 10/newline
break-if at-start-of-line?
start <- prev start
assert start, [delete-to-start-of-line tried to move before start of text]
loop
}
# snip it out
result:address:duplex-list:character <- next start
remove-between start, end
# adjust cursor
before-cursor <- copy start
*editor <- put *editor, before-cursor:offset, before-cursor
left:number <- get *editor, left:offset
*editor <- put *editor, cursor-column:offset, left
]
scenario editor-deletes-to-start-of-line-with-ctrl-u-2 [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
# start on first line (no newline before), press ctrl-u
assume-console [
left-click 1, 2
press ctrl-u
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
# cursor deletes to start of line
screen-should-contain [
. .
.3 .
.456 .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
scenario editor-deletes-to-start-of-line-with-ctrl-u-3 [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
# start past end of line, press ctrl-u
assume-console [
left-click 1, 3
press ctrl-u
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
# cursor deletes to start of line
screen-should-contain [
. .
. .
.456 .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
scenario editor-deletes-to-start-of-final-line-with-ctrl-u [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
# start past end of final line, press ctrl-u
assume-console [
left-click 2, 3
press ctrl-u
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
# cursor deletes to start of line
screen-should-contain [
. .
.123 .
. .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
# ctrl-k - delete text from cursor to end of line (but not the newline)
scenario editor-deletes-to-end-of-line-with-ctrl-k [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
# start on first line, press ctrl-k
assume-console [
left-click 1, 1
press ctrl-k
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
# cursor deletes to end of line
screen-should-contain [
. .
.1 .
.456 .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
after <handle-special-character> [
{
delete-to-end-of-line?:boolean <- equal c, 11/ctrl-k
break-unless delete-to-end-of-line?
<delete-to-end-of-line-begin>
deleted-cells:address:duplex-list:character <- delete-to-end-of-line editor
<delete-to-end-of-line-end>
go-render? <- copy 1/true
return
}
]
def delete-to-end-of-line editor:address:editor-data -> result:address:duplex-list:character, editor:address:editor-data [
local-scope
load-ingredients
# compute range to delete
start:address:duplex-list:character <- get *editor, before-cursor:offset
end:address:duplex-list:character <- next start
{
at-end-of-text?:boolean <- equal end, 0/null
break-if at-end-of-text?
curr:character <- get *end, value:offset
at-end-of-line?:boolean <- equal curr, 10/newline
break-if at-end-of-line?
end <- next end
loop
}
# snip it out
result <- next start
remove-between start, end
]
scenario editor-deletes-to-end-of-line-with-ctrl-k-2 [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
# start on second line (no newline after), press ctrl-k
assume-console [
left-click 2, 1
press ctrl-k
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
# cursor deletes to end of line
screen-should-contain [
. .
.123 .
.4 .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
scenario editor-deletes-to-end-of-line-with-ctrl-k-3 [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
# start at end of line
assume-console [
left-click 1, 2
press ctrl-k
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
# cursor deletes just last character
screen-should-contain [
. .
.12 .
.456 .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
scenario editor-deletes-to-end-of-line-with-ctrl-k-4 [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
# start past end of line
assume-console [
left-click 1, 3
press ctrl-k
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
# cursor deletes nothing
screen-should-contain [
. .
.123 .
.456 .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
scenario editor-deletes-to-end-of-line-with-ctrl-k-5 [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
# start at end of text
assume-console [
left-click 2, 2
press ctrl-k
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
# cursor deletes just the final character
screen-should-contain [
. .
.123 .
.45 .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
scenario editor-deletes-to-end-of-line-with-ctrl-k-6 [
assume-screen 10/width, 5/height
1:address:array:character <- new [123
456]
2:address:editor-data <- new-editor 1:address:array:character, screen:address:screen, 0/left, 10/right
# start past end of text
assume-console [
left-click 2, 3
press ctrl-k
]
run [
editor-event-loop screen:address:screen, console:address:console, 2:address:editor-data
]
# cursor deletes nothing
screen-should-contain [
. .
.123 .
.456 .
.┈┈┈┈┈┈┈┈┈┈.
. .
]
]
# takes a pointer into the doubly-linked list, scans ahead at most 'max'
# positions until the next newline
# beware: never return null pointer.
def before-start-of-next-line original:address:duplex-list:character, max:number -> curr:address:duplex-list:character [
local-scope
load-ingredients
count:number <- copy 0
curr:address:duplex-list:character <- copy original
# skip the initial newline if it exists
{
c:character <- get *curr, value:offset
at-newline?:boolean <- equal c, 10/newline
break-unless at-newline?
curr <- next curr
count <- add count, 1
}
{
return-unless curr, original
done?:boolean <- greater-or-equal count, max
break-if done?
c:character <- get *curr, value:offset
at-newline?:boolean <- equal c, 10/newline
break-if at-newline?
curr <- next curr
count <- add count, 1
loop
}
return-unless curr, original
return curr
]
# takes a pointer into the doubly-linked list, scans back to before start of
# previous *wrapped* line
# beware: never return null pointer
def before-previous-line in:address:duplex-list:character, editor:address:editor-data -> out:address:duplex-list:character [
local-scope
load-ingredients
curr:address:duplex-list:character <- copy in
c:character <- get *curr, value:offset
# compute max, number of characters to skip
# 1 + len%(width-1)
# except rotate second term to vary from 1 to width-1 rather than 0 to width-2
left:number <- get *editor, left:offset
right:number <- get *editor, right:offset
max-line-length:number <- subtract right, left, -1/exclusive-right, 1/wrap-icon
sentinel:address:duplex-list:character <- get *editor, data:offset
len:number <- previous-line-length curr, sentinel
{
break-if len
# empty line; just skip this newline
prev:address:duplex-list:character <- prev curr
return-unless prev, curr
return prev
}
_, max:number <- divide-with-remainder len, max-line-length
# remainder 0 => scan one width-worth
{
break-if max
max <- copy max-line-length
}
max <- add max, 1
count:number <- copy 0
# skip 'max' characters
{
done?:boolean <- greater-or-equal count, max
break-if done?
prev:address:duplex-list:character <- prev curr
break-unless prev
curr <- copy prev
count <- add count, 1
loop
}
return curr
]