# Create a single word alias (proc) for one or more words
# e.g. alias x info exists
# if {[x var]} ...
proc alias {name args} {
	set prefix $args
	proc $name args prefix {
		tailcall {*}$prefix {*}$args
	}
}

# Creates an anonymous procedure
proc lambda {arglist args} {
	set name [ref {} function lambda.finalizer]
	tailcall proc $name $arglist {*}$args
}

proc lambda.finalizer {name val} {
	rename $name {}
}

# Like alias, but creates and returns an anonyous procedure
proc curry {args} {
	set prefix $args
	lambda args prefix {
		tailcall {*}$prefix {*}$args
	}
}

# Returns the given argument.
# Useful with 'local' as follows:
#   proc a {} {...}
#   local function a 
#
#   set x [lambda ...]
#   local function $x
#
proc function {value} {
	return $value
}

# Returns a list of proc filename line ...
# with 3 entries for each stack frame (proc),
# (deepest level first)
proc stacktrace {} {
	set trace {}
	foreach level [range 1 [info level]] {
		lassign [info frame -$level] p f l
		lappend trace $p $f $l
	}
	return $trace
}

# Returns a human-readable version of a stack trace
proc stackdump {stacktrace} {
	set result {}
	set count 0
	foreach {l f p} [lreverse $stacktrace] {
		if {$count} {
			append result \n
		}
		incr count
		if {$p ne ""} {
			append result "in procedure '$p' "
			if {$f ne ""} {
				append result "called "
			}
		}
		if {$f ne ""} {
			append result "at file \"$f\", line $l"
		}
	}
	return $result
}