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Editing Programs

The Curses UI provides a full-screen text editor for writing BASIC programs.

Editor Layout

┌─ MBASIC Editor ─────────────────────────┐
│ 10 PRINT "Hello, World!"                │
│ 20 END                                   │
│ _                                        │
│                                          │
│                                          │
│                                          │
│                                          │
│                                          │
│                                          │
└─ [{{kbd:run:curses}}: Run] [{{kbd:parse:curses}}: Help] ─────────┘

Entering Programs

  1. Type line numbers followed by BASIC statements
  2. Press Enter to add each line
  3. Lines are automatically sorted by number

Example: 

10 PRINT "Hello"_    (press Enter)
20 END_              (press Enter)

Line Numbers

  • Required - Every program line needs a number
  • Range - 0 to 65529
  • Convention - Use multiples of 10 (10, 20, 30...)
  • Sorting - Lines are automatically sorted by number

Editing Existing Lines

To change a line, just retype it with the same number:

10 PRINT "Old text"

Change to: 

10 PRINT "New text"_

The new version replaces the old one.

Deleting Lines

Type just the line number and press Enter:

20_    (press Enter - deletes line 20)

Or use the DELETE command: 

DELETE 20
DELETE 10-30

Inserting Lines

Use line numbers between existing lines:

10 PRINT "First"
30 PRINT "Third"

Insert line 20: 

20 PRINT "Second"_

Result: 

10 PRINT "First"
20 PRINT "Second"
30 PRINT "Third"

Key Action
Arrow Keys Move cursor
Home/End Start/end of line
Page Up/Down Scroll editor

Keyboard Shortcuts

See your UI's keyboard shortcuts documentation for the complete list.

Common shortcuts: - {{kbd:run:curses}} - Run program - {{kbd🆕curses}} - New program (clear) - {{kbd:save:curses}} - Save program - {{kbd:open:curses}} - Load program - {{kbd:parse:curses}} - Help

Renumbering Lines

Use RENUM to renumber your program:

RENUM        (renumber starting from 10, step 10)
RENUM 100    (start from 100)
RENUM 100,20 (start from 100, step 20)

See: RENUM Command

Auto-Numbering

Type AUTO to start automatic line numbering:

AUTO
10 PRINT "Line 1"    (number added automatically)
20 PRINT "Line 2"    (number added automatically)
30 PRINT "Line 3"    (number added automatically)

Exit AUTO mode with {{kbd:continue:curses}} or by typing a line number manually.

See: AUTO Command

Line Editing with EDIT

The EDIT command is supported for compatibility with traditional BASIC, but the Curses UI provides full-screen editing capabilities that make it unnecessary. You can directly navigate to any line and edit it in the full-screen editor.

See: EDIT Command for traditional usage

Direct Mode

Lines without numbers execute immediately:

PRINT 2 + 2
 4

This is useful for testing expressions.

Multiple Statements Per Line

Use colon (:) to separate statements:

10 A = 5 : B = 10 : PRINT A + B

Comments

Use REM or apostrophe for comments:

10 REM This is a comment
20 ' This is also a comment
30 PRINT "Hello"  ' Comment at end of line

Tips

  1. Use 10 increments - Leaves room to insert lines
  2. RENUM periodically - Keep numbers clean
  3. Save often - Don't lose your work
  4. Use comments - Document your code
  5. Test as you go - Run small sections first

Common Mistakes

Forgetting line numbers: 

PRINT "Hello"    ← Executes immediately, not saved

Line numbers out of order: 

30 PRINT "Second"
10 PRINT "First"
The editor automatically sorts them as 10, 30.

Typos in line numbers: 

10 PRINT "Test"
1O PRINT "Oops"   ← Letter O instead of zero
This is a syntax error! The parser will reject "1O" as an invalid line number.

See Also