mk90.guide

Text editor

Named and unnamed buffers, movement, saving and BASIC insertion.

Open a buffer

Use edit path to load an existing regular file or create a new empty buffer at a missing filename. The parent directory must exist. Files longer than 1,280 bytes produce status 20 and are not truncated.

edit without a path is an unnamed scratch buffer. SU+S reports status 16; there is no save-as prompt. For persistent work, open a pathname at the start.

Editor controls

Key sequenceAction
Left / RightMove one character within the buffer.
Up / DownMove vertically by displayed rows, following line wrapping.
BKInsert a line feed.
BackspaceDelete the character immediately before the cursor.
SU, then SSave the current named file; stay in the editor.
SU, then QExit; if changed, ask whether to discard.
R/LToggle lowercase/uppercase state.
FK, then a legend keyInsert its BASIC word in a .bas buffer.

Screen and status

The first row shows the basename, a star for unsaved changes, and case state [A] or [a]. BASIC buffers show BAS; an armed function-key prefix shows FK. An underscore marks the insertion position in the displayed text.

The body uses eight display rows and scrolls to keep the cursor visible. Long physical lines wrap to the 30-column console. Cursor motion follows this displayed layout.

Save and exit

Saving uses the transactional file writer. A successful save clears the changed flag. A failed save leaves the buffer available and does not publish a partial replacement.

SU+Q exits immediately if unchanged. Otherwise it asks SCARTARE? YES + BK (“Discard?”). YES, case-insensitive, discards; another answer returns to editing. A ROM file can be edited in RAM but cannot be saved in place.

BASIC mode

A .bas suffix, ignoring case, selects BASIC insertion. FK is a sequential prefix: press and release FK, then the desired legend key. Pressing FK again toggles the prefix off. An expansion inserts the whole word only if it fits; no partial keyword is inserted at the buffer limit.

For example, FK then R inserts RUN , and FK then P inserts PRINT . This is text entry, not command execution. Factory legends include words unsupported by MBC-16; see the full macro table.

The editor does not compile, execute, syntax-check, indent or colorize the buffer. Leave it, then use MBC and EXEC.

Limits

  • 1,280 bytes total, including line feeds and inserted macro text.
  • Printable single-byte text; no Unicode editing or tab expansion.
  • No undo, selection, clipboard, search/replace, save-as or multiple open buffers.
  • SU+C is not an editor exit command: code 3 is used for up-arrow movement.