187 lines
5 KiB
Python
187 lines
5 KiB
Python
import argparse
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import curses
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import sys
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class Buffer:
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def __init__(self, lines):
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self.lines = lines
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def __len__(self):
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return len(self.lines)
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def __getitem__(self, index):
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return self.lines[index]
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@property
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def bottom(self):
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return len(self) - 1
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def insert(self, cursor, string):
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row, col = cursor.row, cursor.col
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current = self.lines.pop(row)
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new = current[:col] + string + current[col:]
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self.lines.insert(row, new)
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def split(self, cursor):
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row, col = cursor.row, cursor.col
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current = self.lines.pop(row)
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self.lines.insert(row, current[:col])
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self.lines.insert(row + 1, current[col:])
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def delete(self, cursor):
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row, col = cursor.row, cursor.col
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if (row, col) < (self.bottom, len(self[row])):
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current = self.lines.pop(row)
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if col < len(self[row]):
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new = current[:col] + current[col + 1:]
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self.lines.insert(row, new)
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else:
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next = self.lines.pop(row)
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new = current + next
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self.lines.insert(row, new)
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def clamp(x, lower, upper):
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if x < lower:
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return lower
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if x > upper:
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return upper
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return x
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class Cursor:
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def __init__(self, row=0, col=0, col_hint=None):
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self.row = row
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self._col = col
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self._col_hint = col if col_hint is None else col_hint
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@property
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def col(self):
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return self._col
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@col.setter
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def col(self, col):
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self._col = col
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self._col_hint = col
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def _clamp_col(self, buffer):
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self._col = min(self._col_hint, len(buffer[self.row]))
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def up(self, buffer):
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if self.row > 0:
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self.row -= 1
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self._clamp_col(buffer)
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def down(self, buffer):
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if self.row < len(buffer) - 1:
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self.row += 1
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self._clamp_col(buffer)
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def left(self, buffer):
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if self.col > 0:
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self.col -= 1
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elif self.row > 0:
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self.row -= 1
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self.col = len(buffer[self.row])
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def right(self, buffer):
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if self.col < len(buffer[self.row]):
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self.col += 1
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elif self.row < len(buffer) - 1:
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self.row += 1
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self.col = 0
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class Window:
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def __init__(self, n_rows, n_cols, row=0, col=0):
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self.n_rows = n_rows
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self.n_cols = n_cols
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self.row = row
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self.col = col
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@property
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def bottom(self):
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return self.row + self.n_rows - 1
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def up(self, cursor):
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if cursor.row == self.row - 1 and self.row > 0:
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self.row -= 1
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def down(self, buffer, cursor):
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if cursor.row == self.bottom + 1 and self.bottom < len(buffer) - 1:
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self.row += 1
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def horizontal_scroll(self, cursor, left_margin=5, right_margin=2):
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n_pages = cursor.col // (self.n_cols - right_margin)
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self.col = max(n_pages * self.n_cols - right_margin - left_margin, 0)
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def translate(self, cursor):
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return cursor.row - self.row, cursor.col - self.col
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def left(window, buffer, cursor):
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cursor.left(buffer)
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window.up(cursor)
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window.horizontal_scroll(cursor)
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def right(window, buffer, cursor):
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cursor.right(buffer)
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window.down(buffer, cursor)
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window.horizontal_scroll(cursor)
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def main(stdscr):
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parser = argparse.ArgumentParser()
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parser.add_argument("filename")
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args = parser.parse_args()
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with open(args.filename) as f:
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buffer = Buffer(f.read().splitlines())
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window = Window(curses.LINES - 1, curses.COLS - 1)
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cursor = Cursor()
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while True:
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stdscr.erase()
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for row, line in enumerate(buffer[window.row:window.row + window.n_rows]):
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if row == cursor.row - window.row and window.col > 0:
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line = "«" + line[window.col + 1:]
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if len(line) > window.n_cols:
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line = line[:window.n_cols - 1] + "»"
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stdscr.addstr(row, 0, line)
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stdscr.move(*window.translate(cursor))
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k = stdscr.getkey()
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if k == "q":
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sys.exit(0)
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elif k == "KEY_LEFT":
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left(window, buffer, cursor)
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elif k == "KEY_DOWN":
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cursor.down(buffer)
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window.down(buffer, cursor)
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window.horizontal_scroll(cursor)
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elif k == "KEY_UP":
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cursor.up(buffer)
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window.up(cursor)
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window.horizontal_scroll(cursor)
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elif k == "KEY_RIGHT":
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right(window, buffer, cursor)
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elif k == "\n":
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buffer.split(cursor)
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right(window, buffer, cursor)
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elif k in ("KEY_DELETE", "\x04"):
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buffer.delete(cursor)
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elif k in ("KEY_BACKSPACE", "\x7f"):
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if (cursor.row, cursor.col) > (0, 0):
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left(window, buffer, cursor)
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buffer.delete(cursor)
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else:
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buffer.insert(cursor, k)
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for _ in k:
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right(window, buffer, cursor)
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if __name__ == "__main__":
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curses.wrapper(main)
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