Gidubba/readme.md

Gidubba
========

Gidubba (Sumerian for 'stylus') is a simple line editor for the
Thingamajig computer architecture. Its git repository can be found at
https://ahti.space/git/crazyettin/Gidubba and that of Thingamajig at
https://ahti.space/git/crazyettin/Thingamajig.

System requirements
-------------------

Gidubba requires a terminal with local echo at address FFFF and
optionally a line printer at address FFFE and a punched tape reader and
punch at FFFD. If your setup differs from this you may have to modify
the code yourself.

Usage
-----

The commands are individual letters that can be followed by one or two
arguments separated by a comma. The first argument is a target line
number between 0 and FFFF and the second the range of lines between 0
and FF the command affects. Inserting lines to a target that does not
exist or the shortcut hash (#) appends them to the text; otherwise
targets or parts of ranges that do not exist are ignored.

Commands with a single argument:
  * I: Insert a line or lines

Commands with two arguments:
  * D: Delete a line
  * L: List a line

Commands with no argument:
  * P: Print (requires a printer)
  * W: Writes to tape (requires a tape punch)
  * R: Reads from tape (requires a tape reader)
  * H: Halt

Both commands and arguments are case-insensitive. In both the command
prompt as well as when inserting lines sending an escape (^[) will allow
retyping the line in question. To finish inserting lines send a
substitute (^Z): the line on which this is done is not saved.