Skip to content

Variable Management (Curses UI)

The Curses UI provides a visual variable inspector window for viewing and managing variables during program execution and debugging.

Opening the Variables Window

Keyboard Shortcut

Press {{kbd:toggle_variables:curses}} to open the variables window.

Window Layout

┌─── Variables ───────────────────────────┐
│ Name    Type      Value                 │
│ ─────────────────────────────────────── │
│ A       Integer   42                    │
│ B$      String    "Hello World"         │
│ ARR()   Array     Integer[10]           │
│ X!      Single    3.14159               │
│ Total#  Double    1234.56789            │
│                                         │
│ [Tab] Switch  [↑↓] Navigate  [Esc] Close│
└─────────────────────────────────────────┘

Viewing Variables

  • Arrow Keys: Move between variables
  • Page Up/Down: Scroll through long lists
  • Home/End: Jump to first/last variable

Display Information

Each variable shows: - Name: Variable identifier - Type: Integer, String, Single, Double, Array - Value: Current value or array info

Array Inspection

Arrays show: - Type and dimensions: Integer[10] or String[5,5] - Element count - Cannot expand to show individual elements (limitation)

Limitations

Variable Editing Not Available

⚠️ Not Implemented: You cannot edit variable values directly in the variables window.

The variables window is read-only. To modify variables, use immediate mode:

  1. Close variables window (Esc)
  2. Stop program if running ({{kbd:continue:curses}})
  3. Use immediate mode to modify: 
    A = 100
B$ = "New Value"
  4. Continue program or re-run

The variables window provides: - View all variables - See current values - Monitor during execution - Update display in real-time

Filtering and Searching

Search Function

  1. In variables window, press / to search
  2. Type variable name or partial match
  3. Press Enter to find
  4. Press n for next match
  5. Press N for previous match

Filter Options

Press f to cycle through filters: - All: Show all variables - Scalars: Hide arrays - Arrays: Show only arrays - Modified: Show recently changed

Sorting Options

Press s to cycle through sort orders: - Accessed: Most recently accessed (read or written) - shown first (default) - Written: Most recently written to - shown first - Read: Most recently read from - shown first - Name: Alphabetical by variable name

Press d to toggle sort direction (ascending/descending).

Note: The default sort order is "Accessed" with newest first.

During Debugging

Breakpoint Mode

When stopped at a breakpoint: 1. Variables window auto-updates 2. Changed variables highlight briefly 3. Current scope variables shown

Step Mode

During single-stepping: - Window updates after each step - Modified variables flash yellow - Previous values shown in tooltip

Real-time Updates

  • Variables refresh automatically
  • Update frequency: ~100ms during execution
  • Immediate update when paused

Variable Types Display

Type Indicators

Integer    : 42, -100, 32767
String     : "Hello", "Line 1", ""
Single (!) : 3.14159, -0.001, 1.5E10
Double (#) : 3.14159265359, 1.23E-100
Array      : Type[dimensions]

Special Values

Empty String  : ""
Zero         : 0
Uninitialized: (not shown until used)
Error        : [ERROR] or [UNDEFINED]

Window Controls

Resize and Position

  • Ctrl+Arrow: Move window
  • Alt+Arrow: Resize window
  • Ctrl+M: Maximize/restore
  • {{kbd:stop:curses}}: Close window

Display Options

  • v: Toggle value truncation
  • t: Toggle type display
  • d: Show decimal/hex toggle
  • w: Word wrap long strings

Integration with Editor

Synchronized Display

  • Variables window tracks cursor position
  • Shows variables referenced on current line
  • Highlights undefined variables

Quick Navigation

  • Double-click variable name (if mouse enabled)
  • Jumps to first usage in code
  • Shows all references

Performance Considerations

Large Programs

With many variables: - Window may lag slightly - Use filtering to reduce display - Disable auto-update if needed (press u)

Arrays

Large arrays: - Only show dimensions, not contents - Prevents memory/display issues - Use PRINT in immediate mode for elements

Tips and Tricks

  1. Keep window small: Resize to show only needed variables
  2. Use filters: Reduce clutter with type filters
  3. Pin window: Press p to keep always on top
  4. Export list: Press e to save variable list to file
  5. Quick close: Press Esc or q to close

Keyboard Reference

Key Action
{{kbd:toggle_variables:curses}} Open/focus variables window
Esc Close window
Tab Switch between windows
↑↓ Navigate variables
/ Search
f Filter
s Sort
r Refresh
u Toggle auto-update
e Export to file
h Help

Examples

Example 1: Monitoring Loop Variables

10 FOR I = 1 TO 100
20   A = A + I
30   IF I MOD 10 = 0 THEN PRINT I, A
40 NEXT I
- Open variables window - Watch I and A increment - See accumulator pattern

Example 2: String Processing

10 INPUT "Enter text"; T$
20 L = LEN(T$)
30 FOR I = 1 TO L
40   C$ = MID$(T$, I, 1)
50   PRINT C$;
60 NEXT I
- Monitor T, L, I, C - Watch character extraction

Example 3: Array Operations

10 DIM NUMS(10)
20 FOR I = 1 TO 10
30   NUMS(I) = INT(RND * 100)
40 NEXT I
- See NUMS() array declared - Note dimension: Integer[10] - Cannot see individual elements in window

Limitations

Current Limitations

  1. No inline editing: Cannot modify values in window
  2. No array expansion: Cannot view array elements
  3. Limited mouse support: Depends on terminal

Planned Enhancements

  • Full variable editing
  • Array element viewing
  • Better mouse integration
  • Value history tracking

Comparison with Other UIs

Feature Curses CLI Tk Web
Visual window ✅ ❌ ✅ ✅
Edit values ❌ ❌ ✅ ✅
Filtering ✅ ❌ ✅ ✅
Sorting ✅ ❌ ✅ ✅
Real-time ✅ ❌ ✅ ✅

See Also