gDS Exerciser — Command Guide

gDSExer is a terminal program that lets you try your compiled tables without writing a full app. You type short commands (add, delete, …), answer questions, and see the tables update on screen.

It uses the same Python code your real program would use.

Schema language (.dd file): gDSCompiler-keywords-and-naming.md.

Remember: gDSExer tests whether the code works. It does not tell you if your table design is right for your application.

How to start

./gDSExer mySchema.dd

When you run it, it starts by explaining the text found in the square brackets at prompts, like [schema: None].

Main commands

When you see Enter a command from the above list:, type one of these (shortcuts in parentheses):

Work on tables

Type Shortcut What it does
add a Add a new row to a table
delete d Remove rows from a table
set rowstatus sr Change the RowStatus on one row
apply p Fix pointers in other tables after a delete
adjust j Change a pointer by hand
dump u Print one table

For add, delete, rowstatus, and dump, you then pick a table by name or number from the menu.

Scripts and testing

You can test ad-hoc, interactively and also record your inputs to gDSExer and play them back later. You can take checkpoints as you record and on subsequent replays, check your progress against the saved gold files.

Here are the commands involved in recording and playback:

Type Shortcut What it does
rec — Start recording everything you type to a .scr file
play — Run a saved .scr file
return — Go back one level (stop inner script)
s/d — While recording: save a snapshot. While playing back: compare to saved snapshot
quit q Exit

Commands are not case-sensitive. A blank line at the main menu does nothing. A wrong command shows help and is not recorded.

Understanding prompts

gAnimal_Kind [schema: None]:
Text in brackets Meaning
[schema: …] Default from your .dd file
[exer: …] Default from gDSExer
[schema: required] You must type something
[exer: !!! - to abort] Type !!! to cancel
  • Press Enter on an empty line to accept the default.
  • Type **!!!** to cancel the whole command (nothing saved to the script).

What you see on screen

Tables (one line per row):

  Table name       Ref Contents
  ----------       --- --------
  gAnimal          0   Name='Bessie'  Kind='cow'  gFarm_Ref='Farm1'  RowStatus=None
  • The number after the table name is the row index (starts at 0).
  • Pointers show the other row’s name when possible.
  • (???) means a bad or missing pointer.

History (five lines on the right of the menu) — your last commands, newest at the bottom.

Status lines — tell you if you are recording or playing a script:

RECORD: '/path/main.scr' line 42
PLAYBACK: '/path/sub.scr'

Scripts (.scr files)

When you rec, your answers are saved to a .scr file. When you play, gDSExer reads that file instead of waiting for you to type.

A script line can be:

Line starts with Meaning
# gDSExer script Header
# PROMPT: The question that was asked
(normal text) Your answer
# OUT: Text that appeared on screen

Only your answers are replayed. Comments are skipped.

You can nest scripts: record a main script, play a smaller script inside it, then return to go back.

Gold snapshots (s/d)

A gold snapshot is a saved copy of all your tables at one moment — used to check nothing changed later.

While recording, s/d saves to folders like myScript_gold/01/, 02/, …

While playing back, s/d compares live tables to that snapshot. You get PASS or FAIL.

Typical delete then apply flow

  1. delete — remove rows from a table (RAL is saved).
  2. apply — fix pointers in other tables that pointed at deleted rows. You may need to run apply more than once if several tables had pointers.
  3. dump or s/d — check the result.

The screen shows [x] or [ ] next to each apply step so you know what is done.

Example session

rec main.scr       # start recording
play setup.scr     # run a helper script inside the recording
return             # done with helper script
add                # add an animal (answer the prompts)
s/d                # save gold snapshot #01
return             # stop recording
(Restart gDSExer)
play main.scr      # run it again; s/d checks gold at each checkpoint
quit

After each good command you see a short message, press Enter, then all table rows print again.