# -*- tcl -*- tcl.tk//DSL diagram//EN//1.0

proc showcorners {e corners} {
    foreach {c anchor text} $corners {
	circle radius 2 at [$e $c] color red text $text anchor $anchor
    }
}

proc annotate {e} {
    showcorners $e {
	start  se start
	center se center
	end    se end
    }
}

block { annotate [line right up] }
move
block { annotate [line right then down [1 cm] left then right] }
move
block { annotate [arc cw] }
move
block { annotate [spline right then right then down then down [1 cm] left then left] }