MBASIC Curses IDE - Quick Reference Card¶

Note: This reference uses {{kbd:command}} notation for keyboard shortcuts (e.g., {{kbd:run}} is typically ^R for Ctrl+R). Actual key mappings are configurable. To see your current key bindings, press the Help key or check ~/.mbasic/curses_keybindings.json for the full list of default and customized keys.

Starting the IDE¶

python3 mbasic --ui curses [filename.bas]

Editor Commands¶

Key	Command	Description
`{{kbd:new}}`	New	Clear program, start fresh
`{{kbd:open}}`	Load	Load program from file
`{{kbd:save}}`	Save	Save program to file
`{{kbd:quit}}`	Quit	Exit IDE
`{{kbd:help}}`	Help	Open help browser
`ESC`	Menu	Open/close menu bar
Arrow Keys	Navigate	Move cursor in editor

Running Programs¶

Key	Command	Description
`{{kbd:run}}`	Run	Execute current program

Breakpoint Debugging¶

Setting Breakpoints¶

Key	Command	Description
`b` or `F9`	Toggle	Set/clear breakpoint on current line

Visual indicator: ● appears next to line number

At a Breakpoint¶

Status shows: BREAKPOINT at line XX - Press 'c' continue, 's' step, 'e' end

Key	Command	What Happens
`c` or `C`	Continue	Run until next breakpoint or end
`s` or `S`	Step	Execute one line, stop at next
`e` or `E`	End	Stop execution immediately
`ESC`	End	Stop execution immediately

Screen Layout¶

┌──────────────────────────────────────────┐
│ Menu Bar (ESC to activate)               │
├──────────────────────────────────────────┤
│                                          │
│  Editor Window (70%)                     │
│  - Edit your BASIC program here          │
│  - ● markers show breakpoints            │
│                                          │
│                                          │
├──────────────────────────────────────────┤
│                                          │
│  Output Window (30%)                     │
│  - Shows program output                  │
│  - Shows errors                          │
│                                          │
└──────────────────────────────────────────┘

Typical Workflows¶

1. Write and Run¶

1. Type program in editor
2. {{kbd:run}} to run
3. Check output window

2. Debug with Breakpoints¶

1. Set breakpoints on key lines (press 'b')
2. {{kbd:run}} to run
3. At each breakpoint:
   - Press 'c' to continue to next breakpoint
   - Press 's' to step through line-by-line
   - Press 'e' to stop

3. Load, Edit, Save¶

1. {{kbd:open}} to load existing .bas file
2. Edit in editor window
3. {{kbd:run}} to test
4. {{kbd:save}} to save changes

Help System¶

Key	Where	What
`{{kbd:help}}`	Anywhere	Open help browser
Arrow Keys	In help	Scroll up/down
`Space`	In help	Page down
`B`	In help	Page up
`Enter`	In help	Follow link
`U`	In help	Go back/up
`Q` or `ESC`	In help	Exit help

Help Topics¶

Keyboard Shortcuts
BASIC Language Reference
Examples

Debugging Strategy Guide¶

Quick Testing (No Breakpoints)¶

{{kbd:run}} → Watch output → Done

Checkpoint Debugging¶

Set breakpoints at phase boundaries
↓
{{kbd:run}} to start
↓
Press 'c' at each breakpoint to jump to next phase
↓
Verify output at each checkpoint

Detailed Investigation¶

Set breakpoint before problem area
↓
{{kbd:run}} to start
↓
Press 'c' to get to breakpoint
↓
Press 's' to step through suspect code
↓
Press 'e' when done

Loop Analysis¶

Set breakpoint at loop start
↓
{{kbd:run}} to start
↓
Press 's' to watch first few iterations
↓
Press 'c' to let rest complete

Tips¶

✓ Multiple breakpoints: Set as many as you need ✓ Toggle freely: Press 'b' to add/remove anytime (before running) ✓ Continue is your friend: Use 'c' to skip over working code ✓ Step when uncertain: Use 's' only in problem areas ✓ Watch the output: Output window updates as program runs ✓ Use help: Press {{kbd:help}} anytime for full documentation

Common Issues¶

Problem: Breakpoint not stopping - Solution: Make sure ● is visible next to line number

Problem: Can't type in editor - Solution: Press ESC to exit menu mode

Problem: Output not visible - Solution: Output window is at bottom; scroll if needed

Problem: Pressed 's', now every line stops - Solution: Press 'c' to exit step mode

Examples¶

See example programs in the basic/ directory of the MBASIC installation.

More Information¶

Press {{kbd:help}} within the Curses UI to access the built-in help system
See docs/help/ directory for full help documentation
Visit CHOOSING_YOUR_UI.md for UI comparison and selection guide

Pro Tip: Start every debugging session with strategic breakpoints, then use 'c' to jump between them. Only switch to 's' (step) when you find something interesting!