The Io module provides functionality for terminal input/output operations, cursor manipulation, and console formatting. It offers both basic printing capabilities and advanced terminal controls.

Key Concepts

• Terminal input/output operations
• Colored text output
• Cursor manipulation
• Terminal information retrieval
• Multi-line input handling

Basic Usage

Output Operations

; basic printing (with newline)
print "Hello world"
print ["Multiple" "values" "joined"]   ; Multiple values joined

; printing without newline
prints "Loading..."
print "."                             ; Loading....

; print items on separate lines
print.lines ["one" "two" "three"]
; one
; two
; three

Input Operations

; basic input with prompt
name: input "What's your name? "

; single character input
ch: input ø    ; returns single character without echo

; REPL-style input with history
cmd: input.repl ">> "

Colored Output

; using color function
print color #red "Error!"
print color.bold #blue "Important"
print color.underline #green "Success"

; keep color active
prints color.keep #red "This "
prints "and this "
print "all red"

; combining styles
print color.bold.underline #blue "Highlighted"

Cursor Control

; hide/show cursor
cursor false      ; hide cursor
cursor true       ; show cursor

; move cursor to specific position
goto 10 5         ; move to x:10, y:5
print "X"
goto ø 10         ; move to current x, line 10
print "Y"
goto 5 ø          ; move to column 5, current line
print "Z"

; clear screen
clear

Common Patterns

Progress Indicators

; simple progress indicator
loop 1..5 'i [
    prints "."
    pause 500    ; pause for 500ms
]
print ""

; animated spinner
spinner: ["⠋" "⠙" "⠹" "⠸" "⠼" "⠴" "⠦" "⠧" "⠇" "⠏"]
loop 1..20 'i [
    prints "\b"        ; go back one character
    prints spinner\[i % size spinner]
    pause 100
]
print ""

Interactive Menus

clearMenu: function [][
    clear
    cursor false
]

showMenu: function [options][
    selected: 0
    while [true][
        clearMenu
        
        loop options 'opt -> 
            print ["   " opt]
            
        goto 0 selected
        prints "→ "
        
        key: input ø
        case key [
            'w' -> if selected > 0 [dec 'selected]
            's' -> if selected < (size options)-1 [inc 'selected]
            '\r' [
                cursor true
                return selected
            ]
        ]
    ]
]

; usage
choice: showMenu ["Start" "Settings" "Exit"]
print ["Selection:" choice]

Status Updates

; colorful status messages
printStatus: function [kind message][
    case kind [
        "info"    -> print [color #blue "ℹ" message]
        "success" -> print [color #green "✓" message]
        "warning" -> print [color #yellow "⚠" message]
        "error"   -> print [color #red "✗" message]
    ]
]

; usage
printStatus "info" "Loading configuration..."
printStatus "success" "Configuration loaded"
printStatus "warning" "Disk space low"
printStatus "error" "Connection failed"

Terminal Information

; get terminal information
print ["Width:" terminal\width]
print ["Height:" terminal\height]