implement equivalent of vi's 'b' cursor motion

This commit is contained in:
2024-10-24 06:26:40 +01:00
parent 80cdcdccd6
commit 15ff3a111a
3 changed files with 243 additions and 61 deletions

View File

@@ -132,6 +132,22 @@ struct
in
(newApp, drawMsg)
end
fun prevWord (app: app_type) =
let
val {buffer, windowWidth, windowHeight, startLine, cursorIdx, ...} = app
val buffer = LineGap.goToIdx (cursorIdx, buffer)
val cursorIdx = Cursor.prevWord (buffer, cursorIdx)
val buffer = LineGap.goToLine (startLine, buffer)
val drawMsg = TextBuilder.build
(startLine, cursorIdx, buffer, windowWidth, windowHeight)
val newApp = AppWith.bufferAndCursorIdx (app, buffer, cursorIdx)
in
(newApp, drawMsg)
end
fun handleChr (app: app_type, chr) =
case chr of
@@ -142,6 +158,7 @@ struct
| #"0" => moveToLineStart app
| #"$" => moveToLineEnd app
| #"w" => nextWord app
| #"b" => prevWord app
| _ => (app, [])
fun update (app, msg) =

View File

@@ -861,79 +861,79 @@ struct
fun helpNextWordString
( strPos, str, absIdx
, strTl, lineTl
, wordType, hasPassedSpace) =
if strPos = String.size str then
helpNextWordList
(strTl, lineTl, absIdx, wordType, hasPassedSpace)
else
let
val chr = String.sub (str, strPos)
in
if Char.isAlphaNum chr orelse chr = #"_" then
case wordType of
ALPHA_NUM =>
(* current chr is ALPHA_NUM
* and previous chr was also ALPHA_NUM
* so continue iterating *)
helpNextWordString
( strPos + 1, str, absIdx + 1
, strTl, lineTl
, ALPHA_NUM, hasPassedSpace
)
| SPACE=>
(* we moved from SPACE to ALPHA_NUM,
* meaning we may have reached a new word. *)
if hasPassedSpace then
absIdx
else
, prevWordType, hasPassedSpace) =
if strPos = String.size str then
helpNextWordList
(strTl, lineTl, absIdx, prevWordType, hasPassedSpace)
else
let
val chr = String.sub (str, strPos)
in
if Char.isAlphaNum chr orelse chr = #"_" then
case prevWordType of
ALPHA_NUM =>
(* current chr is ALPHA_NUM
* and previous chr was also ALPHA_NUM
* so continue iterating *)
helpNextWordString
( strPos + 1, str, absIdx + 1
, strTl, lineTl
, ALPHA_NUM, true
, ALPHA_NUM, hasPassedSpace
)
| NON_BLANK=>
(* moved from NON_BLANK to ALPHA_NUM,
* meaning we reached new word *)
absIdx
else if Char.isSpace chr then
(* nothing to do on space, except keep iterating *)
helpNextWordString
( strPos + 1, str, absIdx + 1
, strTl, lineTl
, SPACE, true
)
else
(* chr is NON_BLANK. *)
case wordType of
NON_BLANK =>
(* moved from non-blank to non-blank
* so keep iterating *)
helpNextWordString
( strPos + 1, str, absIdx + 1
, strTl, lineTl
, NON_BLANK, hasPassedSpace
)
| ALPHA_NUM =>
(* moved from ALPHA_NUM to non-blank
* so we have reached new word *)
absIdx
| SPACE =>
(* from space to non-blank *)
if hasPassedSpace then
absIdx
else
| SPACE =>
(* we moved from SPACE to ALPHA_NUM,
* meaning we may have reached a new word. *)
if hasPassedSpace then
absIdx
else
helpNextWordString
( strPos + 1, str, absIdx + 1
, strTl, lineTl
, ALPHA_NUM, true
)
| NON_BLANK=>
(* moved from NON_BLANK to ALPHA_NUM,
* meaning we reached new word *)
absIdx
else if Char.isSpace chr then
(* nothing to do on space, except keep iterating *)
helpNextWordString
( strPos + 1, str, absIdx + 1
, strTl, lineTl
, SPACE, true
)
else
(* chr is NON_BLANK. *)
case prevWordType of
NON_BLANK =>
(* moved from non-blank to non-blank
* so keep iterating *)
helpNextWordString
( strPos + 1, str, absIdx + 1
, strTl, lineTl
, NON_BLANK, true
, NON_BLANK, hasPassedSpace
)
end
| ALPHA_NUM =>
(* moved from ALPHA_NUM to non-blank
* so we have reached new word *)
absIdx
| SPACE =>
(* from space to non-blank *)
if hasPassedSpace then
absIdx
else
helpNextWordString
( strPos + 1, str, absIdx + 1
, strTl, lineTl
, NON_BLANK, true
)
end
and helpNextWordList (strings, lines, absIdx, wordType, hasPassedSpace) =
and helpNextWordList (strings, lines, absIdx, prevWordType, hasPassedSpace) =
case (strings, lines) of
(strHd::strTl, lineHd::lineTl) =>
helpNextWordString
( 0, strHd, absIdx, strTl, lineTl, wordType, hasPassedSpace )
( 0, strHd, absIdx, strTl, lineTl, prevWordType, hasPassedSpace )
| (_, _) =>
(* reached end of lineGap;
* return last valid chr position *)
@@ -976,4 +976,169 @@ struct
end
| (_, _) => cursorIdx
end
fun isPrevChrSpace (strPos, str, strTl) =
if strPos > 0 then
let
val prevChr = String.sub (str, strPos - 1)
in
Char.isSpace prevChr
end
else
case strTl of
hd :: _ =>
let
val prevChr = String.sub (hd, String.size hd - 1)
in
Char.isSpace prevChr
end
| [] => true
fun helpPrevWordString
(strPos, str, absIdx, strTl, lineTl, lastWordType) =
if strPos < 0 then
helpPrevWordList
(strTl, lineTl, absIdx, lastWordType)
else
let
val chr = String.sub (str, strPos)
in
if Char.isAlphaNum chr orelse chr = #"_" then
case lastWordType of
ALPHA_NUM =>
(* check if prev chr is space;
* if it is, return current idx
* and if not, keep iterating *)
if isPrevChrSpace (strPos, str, strTl) then
absIdx
else
helpPrevWordString
( strPos - 1, str, absIdx - 1
, strTl, lineTl, ALPHA_NUM
)
| SPACE =>
(* last chr checked was space
* and this chr is ALPHA_NUM
* so keep iterating *)
helpPrevWordString
( strPos - 1, str, absIdx - 1
, strTl, lineTl, ALPHA_NUM
)
| NON_BLANK =>
(* last chr was NON_BLANK
* and this chr is ALPHA_NUM
* and this change is a word break.
* So return idx of last chr. *)
absIdx + 1
else if Char.isSpace chr then
case lastWordType of
SPACE =>
(* nothing to do on double space,
* except keep iterating *)
helpPrevWordString
( strPos - 1, str, absIdx - 1
, strTl, lineTl, SPACE
)
| _ =>
(* last chr was either ALPHA_NUM or NON_BLANK
* and current chr is space
* so we have word break.
* thus, return start of last word *)
absIdx + 1
else
(* is NON_BLANK *)
case lastWordType of
NON_BLANK =>
(* last and current wordType is same
* so keep iterating *)
if isPrevChrSpace (strPos, str, strTl) then
absIdx
else
helpPrevWordString
( strPos - 1, str, absIdx - 1
, strTl, lineTl, NON_BLANK
)
| ALPHA_NUM =>
(* word break since we last chr was ALPHA_NUM
* and this one is NON_BLANK
* so return idx of last chr *)
absIdx + 1
| SPACE =>
(* space means keep iterating *)
helpPrevWordString
( strPos - 1, str, absIdx - 1
, strTl, lineTl, NON_BLANK
)
end
and helpPrevWordList (strings, lines, absIdx, lastWordType) =
case (strings, lines) of
(strHd::strTl, lineHd::lineTl) =>
helpPrevWordString
( String.size strHd - 1, strHd, absIdx
, strTl, lineTl, lastWordType
)
| (_, _) =>
(* reached start of lineGap;
* return 0 which is start idx *)
0
fun startPrevWord (shd, strIdx, absIdx, stl, ltl) =
(* we want to start iterating from previous character
* and ignore the character the cursor is at
* so check previous character *)
if strIdx > 0 then
let
val prevChr = String.sub (shd, strIdx - 1)
val prevWordType = getWordType prevChr
in
helpPrevWordString
(strIdx - 1, shd, absIdx - 1, stl, ltl, prevWordType)
end
else
case (stl, ltl) of
(stlhd::stltl, ltlhd::ltltl) =>
let
val prevIdx = String.size stlhd - 1
val prevChr = String.sub (stlhd, prevIdx)
val prevWordType = getWordType prevChr
in
helpPrevWordString
(prevIdx, stlhd, absIdx - 1, stltl, ltltl, prevWordType)
end
| (_, _) =>
(* tl is empty; just return idx 0 *)
0
(* equivalent of vi's `b` command *)
fun prevWord (lineGap: LineGap.t, cursorIdx) =
let
val {rightStrings, rightLines, leftStrings, leftLines, idx = bufferIdx, ...} = lineGap
in
case (rightStrings, rightLines) of
(shd :: stl, lhd :: ltl) =>
let
(* convert absolute cursorIdx to idx relative to hd string *)
val strIdx = cursorIdx - bufferIdx
in
if strIdx < String.size shd then
(* strIdx is in this string *)
startPrevWord
(shd, strIdx, cursorIdx, leftStrings, leftLines)
else
(* strIdx is in tl *)
(case (stl, ltl) of
(stlhd :: stltl, ltlhd :: ltltl) =>
let
val strIdx = strIdx - String.size shd
val leftStrings = shd :: leftStrings
val leftLines = lhd :: leftLines
in
startPrevWord
(stlhd, strIdx, cursorIdx, leftStrings, leftLines)
end
| (_, _) => cursorIdx)
end
| (_, _) => cursorIdx
end
end

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