% Copyright    Barbara Liskov    1985

x_geometry = proc (spec, defspec: string)
	       returns (int, int, int, int, bool, bool, bool)
    i1: int := string$indexc('x', defspec)
    i2: int
    if i1 = 0
       then i1 := string$indexc('+', defspec)
	    i2 := string$indexc('-', defspec)
	    if i2 > 0  cand  (i1 = 0  cor  i2 < i1)
	       then i1 := i2 end
	    if i1 = 0
	       then i1 := string$size(defspec) + 1 end
       end
    dw: int := int$parse(string$substr(defspec, 2, i1 - 2))
       except others: dw := 1 end
    if i1 <= string$size(defspec)  cand  defspec[i1] = 'x'
       then i1 := i1 + 1 end
    defspec := string$rest(defspec, i1)
    i1 := string$indexc('+', defspec)
    i2 := string$indexc('-', defspec)
    dxp: bool := true
    if i2 > 0  cand  (i1 = 0  cor  i2 < i1)
       then i1 := i2
	    dxp := false
       end
    if i1 = 0
       then i1 := string$size(defspec) + 1 end
    dh: int := int$parse(string$substr(defspec, 1, i1 - 1))
       except others: dh := 1 end
    defspec := string$rest(defspec, i1 + 1)
       except when bounds: defspec := "" end
    i1 := string$indexc('+', defspec)
    dyp: bool := true
    if i1 = 0
       then i1 := string$indexc('-', defspec)
	    if i1 = 0
	       then i1 := string$size(defspec) + 1
	       else dyp := false
	       end
       end
    dx: int := int$parse(string$substr(defspec, 1, i1 - 1))
       except others: dx := 1 end
    dy: int := int$parse(string$rest(defspec, i1 + 1))
       except others: dy := 1 end

    i1 := string$indexc('x', spec)
    if i1 = 0
       then i1 := string$indexc('+', spec)
	    i2 := string$indexc('-', spec)
	    if i2 > 0  cand  (i1 = 0  cor  i2 < i1)
	       then i1 := i2 end
	    if i1 = 0
	       then i1 := string$size(spec) + 1 end
       end
    width: int := int$parse(string$substr(spec, 2, i1 - 2))
       except others: width := dw end
    if width <= 0
       then width := dw end
    if i1 <= string$size(spec)  cand  spec[i1] = 'x'
       then i1 := i1 + 1 end
    spec := string$rest(spec, i1)
    i1 := string$indexc('+', spec)
    i2 := string$indexc('-', spec)
    xplus: bool := true
    place: bool := true
    if i2 > 0  cand  (i1 = 0  cor  i2 < i1)
       then i1 := i2
	    xplus := false
       end
    if i1 = 0
       then i1 := string$size(defspec) + 1
	    place := false
       end
    height: int := int$parse(string$substr(spec, 1, i1 - 1))
       except others: height := dh end
    if height <= 0
       then height := dh end
    spec := string$rest(spec, i1 + 1)
       except when bounds: spec := "" end
    i1 := string$indexc('+', spec)
    yplus: bool := true
    if i1 = 0
       then i1 := string$indexc('-', spec)
	    if i1 = 0
	       then i1 := string$size(spec) + 1
	       else yplus := false
	       end
       end
    x: int := int$parse(string$substr(spec, 1, i1 - 1))
       except others:
		   x := dx
		   xplus := dxp
	      end
    y: int := int$parse(string$rest(spec, i1 + 1))
       except others:
		   y := dy
		   yplus := dyp
	      end
    return(width, height, x, y, xplus, yplus, place)
    end x_geometry