Typed: Libraries and Utilities

Typed: Libraries and Utilities

Typed: Libraries and Utilities

David Van Horn <dvanhorn@ccs.neu.edu>

This package contains a set of typed libraries. It is still under development.

1 util

(require (planet dvanhorn/typed:1:4/util))

cast : (All (T) ((Any -> Boolean : T) Any -> T))

Cast the given value to the type described by the predicate. Note the predicate must be symmetric. The cast will fail at run-time if the value does not satisfy the predicate.

Casting is useful to embed type refinements the programmer can prove that Typed Scheme is not able to reason about.

Examples:
  > (sin pi)
  - : Number
  1.2246467991473532e-16
  > (cast real? (sin pi))
  - : Number
  1.2246467991473532e-16
  > (cast string? 5)
  Cast failed

exact-round : (Real -> Integer)

exact-floor : (Real -> Integer)

exact-ceiling : (Real -> Integer)

exact-truncate : (Real -> Integer)

These operations coerce their result to exact integers.

Examples:
  > (round 3/2)
  - : Number
  2
  > (exact-round 3/2)
  - : Integer
  2
  > (round 2.5)
  - : Number
  2.0
  > (exact-round 2.5)
  - : Integer
  2

It is a contract violation to apply these operations to a non-rational real (i.e., +inf.0, -inf.0, or +nan.0), since there is no exact representation of these values.

Examples:
  > (round +inf.0)
  - : Number
  +inf.0
  > (exact-round +inf.0)
  /Users/dvanhorn/Documents/planet/typed/private/util.ss:2.19:

    (file

  /Users/dvanhorn/Documents/planet/typed/util.ss)
   broke the
  contract (-> rational? any/c) on exact-round; expected
  <rational?>, given: +inf.0

2 2htdp/image

(require (planet dvanhorn/typed:1:4/2htdp/image))

This module provides a typed variant of the 2htdp/image library.

Base types.

Image, Color, and Pen are opaque types with predicates image?, color?, and pen?, respectively.

Angle is a synonym for Real and Nat for Exact-Nonnegative-Integer.

Image-Color is (U Color String Symbol) and the image-color? procedure is its predicate.

Mode is (U 'solid "solid" 'outline "outline") and the mode? procedure is its predicate.

Example:
  > (cast mode? "outline")
  - : Mode
  "outline"

X-Place is (U 'left 'right 'middle 'center "left" "right" "middle" "center") and the x-place? procedure is its predicate.

Example:
  > (cast x-place? "left")
  - : X-Place
  "left"

Y-Place is (U 'top 'bottom 'middle 'center 'baseline "top" "bottom" "middle" "center" "baseline") and the y-place? procedure is its predicate.

Example:
  > (cast y-place? "baseline")
  - : Y-Place
  "baseline"

Pen-Style is (U "solid" 'solid "dot" 'dot "long-dash" 'long-dash "short-dash" 'short-dash "dot-dash" 'dot-dash) and the pen-style? procedure is its predicate.

Example:
  > (cast pen-style? "dot")
  - : Pen-Style
  "dot"

Pen-Cap is (U "round" 'round "projecting" 'projecting "butt" 'butt) and the pen-cap? procedure is its predicate.

Example:
  > (cast pen-cap? "butt")
  - : Pen-Cap
  "butt"

Pen-Join is (U "round" 'round "bevel" 'bevel "miter" 'miter) and the pen-join? procedure is its predicate.

Example:
  > (cast pen-join? "bevel")
  - : Pen-Join
  "bevel"

circle : (Real Mode (U Pen Image-Color) -> Image)

ellipse : (Real Real Mode (U Pen Image-Color) -> Image)

triangle : (Real Mode (U Pen Image-Color) -> Image)

right-triangle : (Real Real Mode (U Pen Image-Color) -> Image)

isosceles-triangle : (Real Angle Mode (U Pen Image-Color) -> Image)

square : (Real Mode (U Pen Image-Color) -> Image)

rectangle : (Real Real Mode (U Pen Image-Color) -> Image)

rhombus : (Real Angle Mode (U Pen Image-Color) -> Image)

regular-polygon : (Real Nat Mode (U Pen Image-Color) -> Image)

star : (Real Mode (U Pen Image-Color) -> Image)

star-polygon : (Real Nat Nat Mode (U Pen Image-Color) -> Image)

polygon : ([Listof Posn] Mode (U Pen Image-Color) -> Image)

line : (Real Real Image-Color -> Image)

add-line : (Image Real Real Real Real (U Pen Image-Color) -> Image)

(Image Real Real Angle Real Real Real Angle Real

(U Pen Image-Color) -> Image)

text : (String Integer Image-Color -> Image)

(String Exact-Positive-Integer Image-Color (Option String)

(U 'default 'decorative 'roman 'script

'swiss 'modern 'symbol 'system)

(U 'normal 'italic 'slant)

(U 'normal 'bold 'light)

Any

-> Image)

overlay : (Image Image Image * -> Image)

overlay/align : (X-Place Y-Place Image Image Image * -> Image)

overlay/xy : (Image Real Real Image -> Image)

underlay : (Image Image Image * -> Image)

underlay/align : (X-Place Y-Place Image Image Image * -> Image)

underlay/xy : (Image Real Real Image -> Image)

beside : (Image Image Image * -> Image)

beside/align : (Y-Place Image Image Image * -> Image)

above : (Image Image Image * -> Image)

above/align : (X-Place Image Image Image * -> Image)

empty-scene : (Real Real -> Image)

place-image : (Image Real Real Image -> Image)

place-image/align : (Image Real Real X-Place Y-Place Image -> Image)

scene+line : (Image Real Real Real Real (U Pen Image-Color) -> Image)

(Image Real Real Angle Real Real Real Angle Real

(U Pen Image-Color) -> Image)

rotate : (Angle Image -> Image)

scale : (Real Image -> Image)

scale/xy : (Real Real Image -> Image)

crop : (Real Real Real Real Image -> Image)

frame : (Image -> Image)

image? : (Any -> Boolean : Image)

image-width : (Image -> Nat)

image-height : (Image -> Nat)

image-baseline : (Image -> Nat)

mode? : (Any -> Boolean : Mode)

image-color? : (Any -> Boolean : Image-Color)

color? : (Any -> Boolean : Color)

make-color : (Nat Nat Nat -> Color)

color-red : (Color -> Nat)

color-green : (Color -> Nat)

color-blue : (Color -> Nat)

y-place? : (Any -> Boolean : Y-Place)

x-place? : (Any -> Boolean : X-Place)

angle? : (Any -> Boolean)

side-count? : (Any -> Boolean)

pen? : (Any -> Boolean : Pen)

make-pen : (Image-Color Real Pen-Style Pen-Cap Pen-Join -> Pen)

pen-color : (Pen -> Image-Color)

pen-width : (Pen -> Real)

pen-style : (Pen -> Pen-Style)

pen-cap : (Pen -> Pen-Cap)

pen-join : (Pen -> Pen-Join)

pen-style? : (Any -> Boolean : Pen-Style)

pen-cap? : (Any -> Boolean : Pen-Cap)

pen-join? : (Any -> Boolean : Pen-Join)

Typed variants of the image teachpack.

Additionally, the library defines the following:

hspace : (Real -> Image)

Creates an image of 0 height and given width.

vspace : (Real -> Image)

Creates an image of 0 width and given height.

above0 : (Image * -> Image)

Extension of above to zero- and un-ary case.

beside0 : (Image * -> Image)

Extension of beside to zero- and un-ary case.

beside/align0 : (Image * -> Image)

Extension of beside/align to zero- and un-ary case.

3 2htdp/universe

(require (planet dvanhorn/typed:1:4/2htdp/universe))

This module provides a typed variant of the 2htdp/universe library.

animate : ((Nat -> Image) -> Nat)

Typed animate.