First video! add operation for sets implemented as ordered lists.

add.py

@@ -0,0 +1,124 @@
+from manimlib.imports import *
+from aanim.list import List
+from aanim.code import code_text, Code
+from aanim.state import State, Value
+
+
+class Add(Scene):
+
+    def construct(self):
+        # present code text
+        code = Code(open('add.txt').read())
+        #code.highlight(4)
+        code.scale(0.5)
+        code.to_edge(LEFT)
+        self.add(code.text)
+        self.wait()
+
+        # present call
+        call = code_text("add(s=\{4,7,-10\}, e=6)")
+        call.to_edge(UP)
+        call.shift(RIGHT * FRAME_WIDTH * 0.25)  # starting from ORIGIN
+        self.play(Write(call))
+
+        # start execution
+        self.play(FadeIn(code.line))
+
+        # variables
+        vars = State([
+            ('s', List([-10, 4, 7])),
+            ('n', Value('0')),
+            ('saux', List([])),
+            ('is\_member', Value('false')),
+            ('d', Value('X')),
+        ])
+
+        # place state in the middle right (not so nice)
+        vars.scale(0.5)
+        vars.next_to(call, DOWN, buff=MED_LARGE_BUFF)
+        vars.move_to(ORIGIN + RIGHT * FRAME_WIDTH * 0.20)
+
+        # parameter s
+        self.play(Write(vars.var('s')))
+        self.play(FadeIn(vars.value('s')))
+
+        # declarations
+        for name in ['n', 'saux', 'is\_member', 'd']:
+            code.play_runstep(self)
+            self.play(Write(vars.var(name)))
+
+        # initializations
+        code.play_runstep(self, 2)
+        self.play(FadeIn(vars.value('n')))
+        code.play_runstep(self, 1)
+        saux = vars.value('saux')
+        saux = vars.value('s').play_list_copy(self, saux)
+        vars.set_value('saux', saux)
+        code.play_runstep(self, 1)
+        self.play(FadeIn(vars.value('is\_member')))       
+
+        # main loop
+        code.play_runstep(self, 3)
+        nvals = [1, 2, 2]
+        branch = [2, 2, 3]
+        for i in range(3):
+            # evaluate condition
+            code.play_hint(self, 'true')
+
+            # update d: head
+            code.play_runstep(self, 1)
+            d = vars.value('d')
+            new_d = saux.play_head(self, d)
+            vars.set_value('d', new_d)
+
+            # evaluate if
+            code.play_runstep(self, branch[i])
+            vars.value('n').play_change(self, str(nvals[i]))
+
+            # tail
+            code.play_runstep(self, 5 - branch[i])
+            saux.play_tail(self)
+
+            # move back to condition
+            code.play_runstep(self, -6)
+
+        # loop terminates
+        code.play_hint(self, 'false')
+
+        # evaluate last if
+        code.play_runstep(self, 9)
+        code.play_hint(self, 'true')
+
+        # list_add_at
+        code.play_runstep(self, 1)
+        vars.value('s').play_add_at(self, 2, 6)
+
+        # list_destroy
+        code.play_runstep(self, 3)
+        self.play(FadeOut(saux))
+        vars.del_value('saux')
+
+        # end: fade out variables
+        code.play_runstep(self, 1)
+        s_var, s_value = vars.var('s'), vars.value('s')
+        vars.del_var('s')
+        self.play(FadeOut(vars))        
+
+        # show result as list
+        g = VGroup(s_var, s_value)
+        # https://github.com/3b1b/manim/issues/865
+        def f(g):
+            g.move_to(ORIGIN + RIGHT * FRAME_WIDTH * 0.25)
+            g.scale(2.0)
+            return g
+        self.play(ApplyFunction(f, g))
+
+        # now as set
+        result = code_text("\{6, 4,7,-10\}")
+        result.replace(s_value)
+        #result.set_height(s.get_height())  # too big
+        result.shift(DOWN * 1.5)  # i would like to animate this
+        #result.next_to(s, DOWN)
+        self.play(FadeIn(result))  #, ApplyMethod(result.shift, DOWN))
+
+        self.wait()

add.txt

@@ -0,0 +1,26 @@
+proc add(in/out s : Set of T, in e : T)
+  var n : nat
+  var saux : List of T
+  var is_member : bool
+  var d : T
+
+  n := 0
+  saux := list_copy(s)
+  is_member := False
+
+  {- encuentro el lugar donde va el elemento -}
+  do (not is_empty(saux) /\ not is_member)
+    d := head(saux)
+    if d = e -> is_member := true
+       d < e -> n := n+1
+       d > e -> skip
+    fi
+    tail(saux)
+  od
+
+  if (not is_member)
+    then list_add_at(s,n,e)
+  fi
+
+  list_destroy(saux)
+end proc