autoclose.tcl

#!/usr/bin/env tclsh

namespace eval ::autofile {
}

rename ::proc ::autofile::proc
rename ::open ::autofile::open
set ::autofile::files(::) {}

::autofile::proc proc {name args body} {
    set ns [uplevel {
        namespace current
    }]
    if {$ns eq "::"} {
        set ns {}
    }
    set name $ns\::$name
    ::autofile::proc $name $args $body
    trace add execution $name leave ::autofile::autoclose
}

::autofile::proc open args {
    set cmd [uplevel {
        if {[dict exists [info frame -2] proc]} {
            namespace which [dict get [info frame -2] proc]
        }
    }]
    set file [::autofile::open {*}$args]
    lappend ::autofile::files($cmd) $file
    puts "don't forget to close $::autofile::files($cmd) for $cmd"
    return $file
}

::autofile::proc ::autofile::autoclose {cmd args} {
    foreach file $::autofile::files($cmd) {
        puts "closing $file for $cmd"
        ::close $file
    }
}

namespace eval ::test {
    proc hi args {
        set f [open /dev/urandom]
        puts [binary encode base64 [read $f 4]]
    }
}

::test::hi

puts bye