How to write procedure which will loop the input line N times in TCL-CodePudding

looking for what could be the "proc_of_for_loop"

puts $fp [proc_of_for_loop abc[$i] 5]

output should be like,

abc0
abc1
abc2
abc3
abc4
abc5

CodePudding user response：

The natural way of doing that in Tcl would be this:

proc n_range {varName from to body} {
    upvar 1 $varName var
    for {set var $from} {$var <= $to} {incr var} {
        uplevel 1 $body
    }
}

n_range i 0 5 {
    puts $fp "abc$i"
}

The upvar and uplevel commands are a major part of the secret sauce of Tcl; they let you create your own control constructs in very little code.

CodePudding user response：

Here's the "substitute and collect" approach. Less general than Donal's solution, but closer to what's requested, and not significantly more complicated IMHO:

proc string_for {string count} {
    for {set i 1} {$i <= count} {incr i} {
        append result [subst $string]
    }
    return $result
}

puts $fp [string_for {abc$i\n} 5]