147 lines
3.7 KiB
Nim
147 lines
3.7 KiB
Nim
# a multiline utf8 text buffer
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import strutils
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import unicode
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import sequtils
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type
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TextBuffer* = ref object
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content: seq[seq[Rune]]
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cursorX: int # rune index
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cursorY: int
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proc newTextBuffer*: TextBuffer =
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new(result)
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result.content = @[]
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result.content.add(@[])
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result.cursorX = 0
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result.cursorY = 0
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proc getLine*(buf: TextBuffer): seq[Rune] =
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buf.content[buf.cursorY]
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proc getContent*(buf: TextBuffer): string =
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buf.content.join("\n")
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proc cline(buf: TextBuffer): var seq[Rune] =
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buf.content[buf.cursorY]
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proc insertRune*(buf: TextBuffer, rune: Rune) =
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buf.cline().insert(rune, buf.cursorX)
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buf.cursorX += 1
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proc isEmpty*(buf: TextBuffer): bool =
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buf.content.len() == 1 and buf.content[0].len() == 0
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proc delete*(buf: TextBuffer) =
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# emulates a delete key
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if buf.cursorX == 0 and buf.cline().len() > 0:
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buf.cline() = buf.cline[1..buf.cline.high()]
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elif buf.cursorX > buf.cline.high():
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if buf.cursorY < buf.content.high():
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# merging lines
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let left = buf.cline()
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buf.content.delete(buf.cursorY)
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buf.cline() = left & buf.cline()
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else:
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buf.cline() = buf.cline[0..buf.cursorX-1] & buf.cline[buf.cursorX+1..buf.cline().high()]
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proc backspace*(buf: TextBuffer) =
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# emulates a backspace key
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if buf.cursorX == 0:
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if buf.cursorY > 0:
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# merging lines
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let right = buf.cline()
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buf.content.delete(buf.cursorY)
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dec buf.cursorY
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buf.cursorX = buf.cline().len()
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buf.cline() &= right
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elif buf.cursorX > buf.cline().high():
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buf.cline() = buf.cline[0..buf.cline().high()-1]
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dec buf.cursorX
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else:
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buf.cline() = buf.cline[0..buf.cursorX-2] & buf.cline[buf.cursorX..buf.cline().high()]
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dec buf.cursorX
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proc moveCursor*(buf: TextBuffer, dx, dy: int) =
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if dx != 0:
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buf.cursorX += dx
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if buf.cursorX < 0:
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buf.cursorX = 0 # TODO switching over lines
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elif buf.cursorX > buf.cline().len():
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buf.cursorX = buf.cline().len() # TODO switching over lines
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if dy != 0:
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buf.cursorY += dy
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if buf.cursorY < 0:
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buf.cursorY = 0
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elif buf.cursorY > buf.content.high():
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buf.cursorY = buf.content.high()
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if buf.cursorX > buf.cline().len():
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buf.cursorX = buf.cline().len()
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proc getCursorPos*(buf: TextBuffer): (int, int) =
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(buf.cursorX, buf.cursorY)
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proc isCursorAtEnd*(buf: TextBuffer): bool =
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return buf.cursorY == buf.content.high() and buf.cursorX > buf.cline().high()
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proc moveToEnd*(buf: TextBuffer, forward: bool) =
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# home/end keys
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if forward:
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buf.cursorX = buf.cline().len()
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else:
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buf.cursorX = 0
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proc enter*(buf: TextBuffer) =
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# emulates an enter in text editors
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let pre = buf.cline[0..buf.cursorX-1]
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let post = buf.cline[buf.cursorX..^1]
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buf.cline() = pre
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inc buf.cursorY
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buf.content.insert(post, buf.cursorY)
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buf.cursorX = 0
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proc newLine*(buf: TextBuffer) =
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# inserts a new empty line below the current one
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# and moves cursor to it
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inc buf.cursorY
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let empty: seq[Rune] = @[]
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buf.content.insert(empty, buf.cursorY)
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buf.cursorX = 0
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proc getLineCount*(buf: TextBuffer): int =
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buf.content.len()
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proc lines*(buf: TextBuffer): seq[seq[Rune]] =
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buf.content
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proc isLastLine*(buf: TextBuffer): bool =
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buf.cursorY == buf.content.high()
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proc isFistLine*(buf: TextBuffer): bool =
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buf.cursorY == 0
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proc isLineEmpty*(buf: TextBuffer): bool =
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buf.cline().len() == 0
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proc stripFinalNewline*(buf: TextBuffer) =
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# nothing if only 1 line
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if buf.content.len() <= 1:
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return
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# nothing if last line not empty
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if buf.content[buf.content.high()].len() > 0:
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return
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# adjust cursor
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if buf.cursorY == buf.content.high():
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dec buf.cursorY
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buf.cursorX = buf.cline().len()
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# pop final element
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buf.content.del(buf.content.high())
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