Added documentaion comments for textmanip

This commit is contained in:
Sasha Koshka 2023-03-31 19:40:25 -04:00
parent 03dfcf02bf
commit 50d7d74097

View File

@ -2,12 +2,18 @@ package textmanip
import "unicode"
// Dot represents a cursor or text selection. It has a start and end position,
// referring to where the user began and ended the selection respectively.
type Dot struct { Start, End int }
// EmptyDot returns a zero-width dot at the specified position.
func EmptyDot (position int) Dot {
return Dot { position, position }
}
// Canon places the lesser value at the start, and the greater value at the end.
// Note that a canonized dot does not in all cases correspond directly to the
// original.
func (dot Dot) Canon () Dot {
if dot.Start > dot.End {
return Dot { dot.End, dot.Start }
@ -16,10 +22,12 @@ func (dot Dot) Canon () Dot {
}
}
// Empty returns whether or not the
func (dot Dot) Empty () bool {
return dot.Start == dot.End
}
// Add shifts the dot to the right by the specified amount.
func (dot Dot) Add (delta int) Dot {
return Dot {
dot.Start + delta,
@ -27,6 +35,7 @@ func (dot Dot) Add (delta int) Dot {
}
}
// Add shifts the dot to the left by the specified amount.
func (dot Dot) Sub (delta int) Dot {
return Dot {
dot.Start - delta,
@ -34,6 +43,7 @@ func (dot Dot) Sub (delta int) Dot {
}
}
// Constrain constrains the dot's start and end from zero to length (inclusive).
func (dot Dot) Constrain (length int) Dot {
if dot.Start < 0 { dot.Start = 0 }
if dot.Start > length { dot.Start = length}
@ -42,16 +52,20 @@ func (dot Dot) Constrain (length int) Dot {
return dot
}
// Width returns how many runes the dot spans.
func (dot Dot) Width () int {
dot = dot.Canon()
return dot.End - dot.Start
}
// Slice returns the subset of text that the dot covers.
func (dot Dot) Slice (text []rune) []rune {
dot = dot.Canon().Constrain(len(text))
return text[dot.Start:dot.End]
}
// WordToLeft returns how far away to the left the next word boundary is from a
// given position.
func WordToLeft (text []rune, position int) (length int) {
if position < 1 { return }
if position > len(text) { position = len(text) }
@ -68,6 +82,8 @@ func WordToLeft (text []rune, position int) (length int) {
return
}
// WordToRight returns how far away to the right the next word boundary is from
// a given position.
func WordToRight (text []rune, position int) (length int) {
if position < 0 { return }
if position > len(text) { position = len(text) }
@ -84,6 +100,7 @@ func WordToRight (text []rune, position int) (length int) {
return
}
// WordAround returns a dot that surrounds the word at the specified position.
func WordAround (text []rune, position int) (around Dot) {
return Dot {
WordToLeft(text, position),
@ -91,6 +108,9 @@ func WordAround (text []rune, position int) (around Dot) {
}
}
// Backspace deletes the rune to the left of the dot. If word is true, it
// deletes up until the next word boundary on the left. If the dot is non-empty,
// it deletes the text inside of the dot.
func Backspace (text []rune, dot Dot, word bool) (result []rune, moved Dot) {
dot = dot.Constrain(len(text))
if dot.Empty() {
@ -109,6 +129,9 @@ func Backspace (text []rune, dot Dot, word bool) (result []rune, moved Dot) {
}
}
// Delete deletes the rune to the right of the dot. If word is true, it deletes
// up until the next word boundary on the right. If the dot is non-empty, it
// deletes the text inside of the dot.
func Delete (text []rune, dot Dot, word bool) (result []rune, moved Dot) {
dot = dot.Constrain(len(text))
if dot.Empty() {
@ -131,6 +154,7 @@ func Delete (text []rune, dot Dot, word bool) (result []rune, moved Dot) {
}
}
// Lift removes the section of text inside of the dot, and returns a copy of it.
func Lift (text []rune, dot Dot) (result []rune, moved Dot, lifted []rune) {
dot = dot.Constrain(len(text))
if dot.Empty() {
@ -147,6 +171,8 @@ func Lift (text []rune, dot Dot) (result []rune, moved Dot, lifted []rune) {
return
}
// Type inserts one of more runes into the text at the dot position. If the dot
// is non-empty, it replaces the text inside of the dot with the new runes.
func Type (text []rune, dot Dot, characters ...rune) (result []rune, moved Dot) {
dot = dot.Constrain(len(text))
if dot.Empty() {
@ -167,6 +193,8 @@ func Type (text []rune, dot Dot, characters ...rune) (result []rune, moved Dot)
}
}
// MoveLeft moves the dot left one rune. If word is true, it moves the dot to
// the next word boundary on the left.
func MoveLeft (text []rune, dot Dot, word bool) (moved Dot) {
dot = dot.Canon().Constrain(len(text))
distance := 0
@ -180,6 +208,8 @@ func MoveLeft (text []rune, dot Dot, word bool) (moved Dot) {
return
}
// MoveRight moves the dot right one rune. If word is true, it moves the dot to
// the next word boundary on the right.
func MoveRight (text []rune, dot Dot, word bool) (moved Dot) {
dot = dot.Canon().Constrain(len(text))
distance := 0
@ -193,6 +223,8 @@ func MoveRight (text []rune, dot Dot, word bool) (moved Dot) {
return
}
// SelectLeft moves the end of the dot left one rune. If word is true, it moves
// the end of the dot to the next word boundary on the left.
func SelectLeft (text []rune, dot Dot, word bool) (moved Dot) {
dot = dot.Constrain(len(text))
distance := 1
@ -203,6 +235,8 @@ func SelectLeft (text []rune, dot Dot, word bool) (moved Dot) {
return dot
}
// SelectRight moves the end of the dot right one rune. If word is true, it
// moves the end of the dot to the next word boundary on the right.
func SelectRight (text []rune, dot Dot, word bool) (moved Dot) {
dot = dot.Constrain(len(text))
distance := 1