Trying to decide if Tcl is worth learning.

mandel.tcl

#!/usr/bin/tclsh

set rows 40
set cols 80

if {$argc == 2} {
    set rows [lindex $argv 0]
    set cols [lindex $argv 1]
} elseif {$argc != 0} {
    puts "Invalid arguments! Need two (rows, cols) or none."
    exit
}

proc mandel {real imag} {
    set z_r 0.0
    set z_i 0.0

    for {set i 0} {$i < 20} {incr i} {
        set z_r_t [expr $z_r * $z_r - $z_i * $z_i + $real]
        set z_i_t [expr 2 * $z_r * $z_i + $imag]

        set z_r $z_r_t
        set z_i $z_i_t

        if {$z_r * $z_r + $z_i * $z_i > 4} {
            return [expr {$i < 5 ? " " : $i < 10 ? "░" : $i < 15 ? "▒" : "▓"}]
        }
    }

    return "█"
}

for {set i 0} {$i < $rows} {incr i} {
    for {set j 0} {$j < $cols} {incr j} {
        puts -nonewline [mandel [expr  4.0 * $j / $cols - 2]\
                                [expr -4.0 * $i / $rows + 2]]
    }
    puts ""
}