#set document(title: "11.5 Using modules with classes", author: "OpenStax / XYZ Homework")
#set page(width: 8.5in, height: auto, margin: 1in)
#import "@preview/cetz:0.5.2"
#set text(font: ("STIX Two Text", "Libertinus Serif", "New Computer Modern"), size: 10.5pt, lang: "en")
#show math.equation: set text(font: ("STIX Two Math", "New Computer Modern Math"))
#set par(justify: true, leading: 0.62em, spacing: 0.9em)
#set enum(spacing: 1.1em)   // room between list items so tall inline fractions don't collide
#set list(spacing: 1.1em)
#set table(stroke: 0.5pt + rgb("#c7ccd3"))

#let BLUE = rgb("#183B6F")     // brand navy — section bars + example/solution labels (white on navy 11.09:1)
#let ORANGE = rgb("#A94509")   // brand primary-700 — AA-safe deep orange for TEXT (5.93:1 on white; raw brand #F37021 is 2.94:1 and must never carry text)
#let RED = rgb("#DC2626")      // brand error-600
#let GREEN = rgb("#059669")    // brand success-600 (decoration only; small green text uses green-text #007942)

#show heading.where(level: 1): it => block(width: 100%, above: 0pt, below: 16pt,
  fill: gradient.linear(BLUE, rgb("#2C5AA0")), inset: (x: 14pt, y: 12pt), radius: 3pt,
  text(fill: white, weight: "bold", size: 19pt, it.body))
#show heading.where(level: 2): it => block(width: 100%, above: 18pt, below: 10pt,
  fill: BLUE, inset: (x: 10pt, y: 6pt), radius: 2pt,
  text(fill: white, weight: "bold", size: 12pt, it.body))
#show heading.where(level: 3): it => text(fill: ORANGE, weight: "bold", size: 12.5pt, it.body)
#show heading.where(level: 4): it => text(fill: BLUE, weight: "bold", size: 10.5pt, it.body)

#let examplebox(label, title, body) = block(width: 100%, breakable: true,
  fill: rgb("#EFF1F5"), stroke: 0.5pt + rgb("#CFDDF0"), radius: 4pt, inset: 10pt,
  above: 12pt, below: 12pt)[
  #block(below: 6pt)[#box(fill: BLUE, inset: (x: 6pt, y: 2pt), radius: 2pt,
    text(fill: white, weight: "bold", size: 8.5pt, label)) #h(0.4em) #strong[#title]]
  #body]

// rail = decorative left rule (raw brand token); labelcolor = AA-safe label text shade
#let notebox(label, rail, labelcolor, tint, body) = block(width: 100%, breakable: true, fill: tint,
    stroke: (left: 3pt + rail), inset: (left: 10pt, rest: 8pt), radius: (right: 4pt),
    above: 11pt, below: 11pt)[
    #text(fill: labelcolor, weight: "bold", size: 7.5pt, tracking: 0.5pt)[#upper(label)]
    #linebreak() #body]

#let solutionbox(body) = block(above: 4pt, below: 8pt)[
  #text(fill: BLUE, weight: "bold", size: 8.5pt)[Solution] #linebreak() #body]

#let figph(msg) = block(width: 100%, height: 60pt, fill: rgb("#f6f7f9"),
  stroke: (paint: rgb("#c7ccd3"), dash: "dashed"), radius: 4pt, inset: 10pt)[
  #align(center + horizon, text(fill: rgb("#889"), style: "italic", size: 9pt, msg))]

// Standardize inlined figure sizes: measure the natural CeTZ canvas, then scale to a
// consistent envelope (aspect-aware; see build_typst.py FIG_* constants). Unlike the
// print preamble, dimensions are FLOORED: in an editor a user can trim a figure to a
// degenerate 1-D shape (a bare line), and w/h or tw/w would then divide by zero.
#let _STD_W = 3.5
#let _WIDE_W = 5.6
#let _MAX_H = 3.4
#let _ASPECT_WIDE = 2.2
#let _UPSCALE_MAX = 1.15
#let stdfig(body) = context {
  let m = measure(body)
  let w = calc.max(m.width / 1in, 0.01)
  let h = calc.max(m.height / 1in, 0.01)
  let tw = if w / h > _ASPECT_WIDE { _WIDE_W } else { _STD_W }
  let s = calc.min(tw / w, _MAX_H / h, _UPSCALE_MAX)
  align(center, box(scale(x: s * 100%, y: s * 100%, reflow: true, body)))
}

#show figure: set block(breakable: false)
#set figure(gap: 8pt)
#show figure.caption: set text(size: 8.5pt, fill: rgb("#555"))


  
== 11.5#h(0.6em)Using modules with classes


  
    
=== Learning objectives


    By the end of this section you should be able to


    - Construct an import statement that selectively imports classes.
- Create an alias to import a module.


  
  
    
=== Importing classes from modules


    Import statements, as discussed in the Modules chapter, allow code from other files, including classes, to be imported into a program. Accessing an imported class depends on whether the whole module is imported or only selected parts.


    Multiple classes can be grouped in a module. For good organization, classes should be grouped in a module only if the grouping enables module reuse, as a key benefit of modules is reusability.


    #notebox("Note", rgb("#8a94a6"), rgb("#556666"), rgb("#f7f8fa"))[
#emph[Importing classes from files]


      #link("https://www.openstax.org/r/importing-classes")[Importing classes from files; ch 11, video 10]
]


    #notebox("Note", rgb("#8a94a6"), rgb("#556666"), rgb("#f7f8fa"))[
#emph[Importing classes]
]


  
  
    
=== Using aliases


    #strong[Aliasing] allows the programmer to use an alternative name for imported items. Ex: import triangle as tri allows the program to refer to the triangle module as tri. Aliasing is useful to avoid name collisions but should be used carefully to avoid confusion.


    #examplebox("Example 1")[Using aliasing to import character][
#emph[character.py]


      
    class Level:
      def \_\_init\_\_(self, level=1):
        self.level = level
        ...
      def level\_up(self):
        ...
    class XP:
      def \_\_init\_\_(self, XP=0):
        self.XP = XP
        ...
      def add\_xp(self, num):
        ...
      #emph[main.py]


      
    import character as c
    
    bard\_level = c.Level(1)
    bard\_XP = c.XP(0)
    bard\_XP.add\_xp(300)
    bard\_level.level\_up()
    ...
]


    #notebox("Note", rgb("#8a94a6"), rgb("#556666"), rgb("#f7f8fa"))[
#emph[Using an alias]


      Consider the example above. Suppose a program imports the character module using import character as game\_char.
]


  
  #notebox("Note", rgb("#8a94a6"), rgb("#556666"), rgb("#f7f8fa"))[
#emph[Missing import statement]


    Add the missing import statement to the top of the file. Do not make any changes to the rest of the code. In the end, the program should run without errors.


    from math import sqrt
\# Import statement

def is\_prime(n):
    if n \< 2:
        return False
    for i in range(2, int(sqrt(n)) + 1):
        if n % i == 0:
            return False
    return True

def test(num):
    for n in range(num):
        if is\_prime(n):
            print(n, "is prime")
        else:
            print(n, "is NOT prime")

def pizza\_rate(size, price):
    pizza = Circle(size/2)
    return price / pizza.area()

test(10)
print()
print("  Small for \$4.99:", pizza\_rate(10, 4.99))
print(" Medium for \$5.99:", pizza\_rate(12, 5.99))
print("  Large for \$7.99:", pizza\_rate(14, 7.99))
print("X-Large for \$9.99:", pizza\_rate(16, 9.99))
]


  #notebox("Note", rgb("#8a94a6"), rgb("#556666"), rgb("#f7f8fa"))[
#emph[Missing class import statement]


    Add the missing class import statement to the top of the file. Import only a class, not a full module. Do not make any changes to the rest of the code. In the end, the program should run without errors.


    \# Import statement

class Sequence:
    nums = \[0, 1\]

    def \_\_init\_\_(self):
        for i in range(2, 10):
            self.nums.append(self.nums\[i-2\] + self.nums\[i-1\])


fibs = Sequence()
print(fibs.nums)
sqs = Squares()
print(sqs.nums)
]