Initial support for bidirectional editing.
Makefile.in (obj): Include bidi.o. (bidi.o): New target. makefile.w32-in (OBJ1): Add $(BLD)/bidi.$(O). ($(BLD)/bidi.$(O)): New target. bidi.c: New file. buffer.h (struct buffer): New members bidi_display_reordering and bidi_paragraph_direction. buffer.c (init_buffer_once): Initialize bidi_display_reordering and bidi_paragraph_direction. (syms_of_buffer): Declare Lisp variables bidi-display-reordering and bidi-paragraph-direction. (Fbuffer_swap_text): Swap the values of bidi_display_reordering and bidi_paragraph_direction. dispextern.h (BIDI_MAXLEVEL, BIDI_AT_BASE_LEVEL): New macros. (bidi_type_t, bidi_dir_t): New types. (bidi_saved_info, bidi_stack, bidi_it): New structures. (struct it): New members bidi_p, bidi_it, paragraph_embedding, prev_stop, base_level_stop, and eol_pos. (bidi_init_it, bidi_get_next_char_visually): New prototypes. (IT_STACK_SIZE): Enlarge to 5. (struct glyph_row): New member reversed_p. <string_buffer_position>: Update prototype. (PRODUCE_GLYPHS): Set the reversed_p flag in the iterator's glyph_row if bidi_it.paragraph_dir == R2L. (struct glyph): New members resolved_level and bidi_type. dispnew.c (direct_output_forward_char): Give up if we need bidi processing or buffer's direction is right-to-left. (prepare_desired_row): Preserve the reversed_p flag. (row_equal_p): Compare the reversed_p attributes as well. xdisp.c (init_iterator): Initialize it->bidi_p. Call bidi_init_it and set it->paragraph_embedding from the current buffer's value of bidi_paragraph_direction. (reseat_1): Initialize bidi_it.first_elt. (set_iterator_to_next, next_element_from_buffer): Use the value of paragraph_embedding to determine the paragraph direction. (set_iterator_to_next): Under bidi reordering, call bidi_get_next_char_visually. Call bidi_paragraph_init if the new_paragraph flag is set in the bidi iterator. (next_element_from_buffer): If bidi_it.first_elt is set, initialize paragraph direction and find the first character to display in the visual order. If reseated to a middle of a line, prime the bidi iterator starting at the line's beginning. Handle the situation where we overstepped stop_charpos due to non-linearity of the bidi iteration. Likewise for when we back up beyond the previous stop_charpos. When moving across stop_charpos, record it in prev_stop. (display_line): Set row->end and it->start for the next row to the next character in logical order. Always extend reversed_p rows to the end of line, even if they end at ZV. Copy the reversed_p flag to the next glyph row. Keep calling set_cursor_from_row for bidi-reordered rows even if we already have a possible candidate for cursor position. Set row_end after all the row's glyphs have been produced, by looping over the glyphs. Record the position after EOL in it->eol_pos, and use it to set end_pos of the last row produced for a continued line. <Qright_to_left, Qleft_to_right>: New variables. (syms_of_xdisp): Initialize and staticpro them. (string_buffer_position_lim): New function. (string_buffer_position): Most of code moved to string_buffer_position_lim. Last argument and return value are now EMACS_INT; all callers changed. (set_cursor_from_row): Rewritten to support bidirectional text and reversed glyph rows. (text_outside_line_unchanged_p, try_window_id): Disable optimizations if we are reordering bidirectional text and the paragraph direction can be affected by the change. (append_glyph, append_composite_glyph) (produce_image_glyph, append_stretch_glyph): Set the resolved_level and bidi_type members of each glyph. (append_glyph): If the glyph row is reversed, prepend the glyph rather than appending it. (handle_stop_backwards): New function. (reseat_1, pop_it, push_it): Set prev_stop and base_level_stop. (reseat): call handle_stop_backwards to recompute prev_stop and base_level_stop for the new position. (handle_invisible_prop): Under bidi iteration, skip invisible text using bidi_get_next_char_visually. If we are `reseat'ed, init the paragraph direction. Update IT->prev_stop after skipping invisible text. (move_it_in_display_line_to): New variables prev_method and prev_pos. Compare for strict equality in BUFFER_POS_REACHED_P. (try_cursor_movement): Examine all the candidate rows that occlude point, to return the best match. If rows are bidi-reordered and point moved backwards, back up to the row that is not a continuation line, and start looking for a suitable row from there. term.c (append_glyph): Reverse glyphs by pre-pending them, rather than appending, if the glyph_row's reversed_p flag is set. Set the resolved_level and bidi_type members of each glyph. .gdbinit (pbiditype): New command. (pgx): Use it to display bidi level and type of the glyph. (pitx): Display some bidi information about the iterator. (prowlims, pmtxrows): New commands. files.el: Make bidi-display-reordering safe variable for boolean values. mule.texi (International): Mention support of bidirectional editing. (Bidirectional Editing): New section. HELLO: Reorder Arabic and Hebrew into logical order, and insert RLM before the opening paren, to make the display more reasonable. Add setting for bidi-display-reordering in the local variables section. NEWS: Mention initial support for bidirectional editing.
Showing with 3623 additions and 221 deletions