ASCII ruler generation
Not going to beat the dynamic languages today, but anyway...

Haskell, 341

import Data.List
main=interact$unlines.m.map read.words
m[l,r]|r&gt;l=ᴛ.("┌│││└":).(++["┬   ─","┐│││┘"]).ʀ.t.ʀ.t.takeWhile((&gt;4).length).ᴛ$[c"┬",c"│    ",[l,l+10..r]&gt;&gt;=h.show,c" ",c"─"]|True=["NaR"]
h s=p s$length s;p s@('-':_)l=r(6-l)ꜱ++s++r 4ꜱ;p s l=r 5ꜱ++s++r(5-l)ꜱ
ᴛ=transpose;ʀ=reverse;r=replicate;c=cycle
ꜱ=' ';t l@(c:o)|c!!2==ꜱ=t o|True=l


I took the liberty of exchanging the actual ASCII characters with better-looking unicode box drawing chars.

$ echo "-50 30" | runhaskell  def0.hs
┌┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┬┐
│  │    │    │    │    │    │    │    │    │    │    │    │    │    │    │    │    │  │
│-50       -40       -30       -20       -10         0         10        20        30 │
│                                                                                     │
└─────────────────────────────────────────────────────────────────────────────────────┘