module Deduce(ded, turnstile, (|-), eps) where

import SlideWare
import Symbol

ded :: [Pict] -> Pict -> Pict
ded ps c =
    let t = label "top" (hblAppend (spacing gapSize : ps))
	l = lineWidth 2 $ line (findLB "top" t, findRB "top" t)
	tl = ltSuperimpose [t, l]
	tlc = vcAppend [tl, c]
    in  tlc

turnstile :: Pict
turnstile =
    let b = label "b" $ blank (gapSize * 0.5) (gapSize * 0.6)
	lv = line (findLB "b" b, findLT "b" b)
	hv = line (findLC "b" b, findRC "b" b)
	ts = lineWidth 2 $ ltSuperimpose [lv, hv]
    in  ccSuperimpose [ts, blank 0 gapSize]

(|-) :: Pict -> Pict -> Pict
a |- b = hblAppend [spacing (gapSize/3), a, turnstile, b]

x `eps` y = hblAppend [x, sepsilon, y]