package require Tcl 8.6
namespace import tcl::mathfunc::min
namespace import tcl::mathfunc::max

proc {#} args {}

# short aliases for common things

proc llen {lst} { return [llength $lst] }
proc slen {str} { return [string length $str] }
proc trim args { return [uplevel [concat string trim $args]] }
proc replace {str a b} { return [string map [list $a $b] $str] }

# sum and product

proc ladd {list} {
    set t 0
    foreach x $list { incr t $x }
    return $t
}

proc lmul {list} {
    set p 1
    foreach x $list { set p [expr {$p * $x}] }
    return $p
}

# split s on a substring
proc splitstr {s sep} {
    # replace $sep with ascii char 30, aka "record separator"
    return [split [replace $s $sep "\x1E"] "\x1E"]
}

proc must_regexp args {
    if {! [uplevel [concat regexp $args]]} {
        error "regexp failed"
    }
}

# transpose a list of strings
#
#     % transpose {abc 123}
#     a1 b2 c3
#     % transpose a1 b2 c3
#     abc 123
#
proc transpose strings {
    set out {}
    set C [slen [lindex $strings 0]]
    for {set i 0} {$i < $C} {incr i} {
        set column {}
        foreach row $strings {
            lappend column [string index $row $i]
        }
        lappend out [join $column ""]
    }
    return $out
}