Bring math, random and time symbols into global namespace

README.md

@@ -96,6 +96,11 @@ described below.
 
 Here's some places that have seen recent work
 
+ * Changed the builtin math, time and random functions to no longer
+   include the math., time. or random. prefixes. This makes them more
+   convenient to use. To retain compatibility with Python, you can
+   use 'from math import *' which Snek will ignore.
+
  * [Mu](https://codewith.mu/) version 1.2.0 has Snek support built in
    now. Mu is an IDE designed for new Python users that offers a more
    polished alternative to the simple Snek IDE provide with snek.

doc/lessons/lesson-1/lesson-1-snekboard.adoc

@@ -274,7 +274,7 @@ things in front of it:
 ----
 > *while True:*
 +    *print(read(A1))*
-+    *time.sleep(1)*
++    *sleep(1)*
 +
 0.3484738
 0.3829738
@@ -289,7 +289,7 @@ things in front of it:
 *Ctrl+C*
 ----
 
-You'll need to hit kbd:[Enter] after *time.sleep(1)* to get the
+You'll need to hit kbd:[Enter] after *sleep(1)* to get the
 program to run. Hit kbd:[Ctrl+C] when you're done testing to stop the
 program.
 

doc/lessons/lesson-2/lesson-2-line-bug.adoc

@@ -80,7 +80,7 @@ light sensor using something like this (use <Ctrl>C to stop):
 
 	while True:
 		print(read(A1))
-		time.sleep(1)
+		sleep(1)
 
 Consider:
 

doc/lessons/lesson-3/bumper-car.py

@@ -36,8 +36,8 @@ def WaitUntilCloseOtherDir():
 
 
 def WaitRandom():
-    wait = 0.25 + random.randrange(10) / 10
-    time.sleep(wait)
+    wait = 0.25 + randrange(10) / 10
+    sleep(wait)
 
 
 def Spin():
@@ -62,15 +62,15 @@ def BumperCar():
 
         # Back up a bit and spin around
         MoveOneDir()
-        time.sleep(0.5)
+        sleep(0.5)
         SpinRandom()
 
         MoveOneDir()
         WaitUntilCloseOneDir()
 
         # Back up a bit and spin around
         MoveOtherDir()
-        time.sleep(0.5)
+        sleep(0.5)
         SpinRandom()
 
         MoveOtherDir()

doc/lessons/lesson-3/lesson-3-bumper-car.adoc

@@ -138,7 +138,7 @@ distance:
 ----
 > *while True:*
 +   *print(read(A8))*
-+   *time.sleep(1)*
++   *sleep(1)*
 + 
 0.162149
 0.1758242
@@ -197,30 +197,30 @@ do this, we'll spin in place.
 To make our robot less predictable, let's have it spin a random
 amount. Random numbers are like the roll of a die; you can't predict
 the value. Snek can generate random numbers using the
-`random.randrange` function. `random.randrange` takes one value, and
+`randrange` function. `randrange` takes one value, and
 will generate a random number from zero to one less than this value.
 So, if you want a random number from the set { 0, 1, 2, 3, 4, 5 },
-you'd use `random.randrange(6)`. We can do arithmetic on the number to
+you'd use `randrange(6)`. We can do arithmetic on the number to
 adjust the range further.
 
 Let's explore that:
 
 [subs="verbatim,quotes"]
 ----
-> *random.randrange(6)*
+> *randrange(6)*
 3
-> *random.randrange(6)*
+> *randrange(6)*
 1
 > *for i in range(5):*
-+     *print(random.randrange(6))*
++     *print(randrange(6))*
 + 
 5
 1
 4
 0
 3
 > *for i in range(5):*
-+     *print(random.randrange(6) + 1)*
++     *print(randrange(6) + 1)*
 + 
 6
 5
@@ -236,8 +236,8 @@ say between 1 and 6 seconds:
 [source,python,subs="verbatim,quotes"]
 ----
 def WaitRandom():
-    wait = random.randrange(6) + 1
-    time.sleep(wait)
+    wait = randrange(6) + 1
+    sleep(wait)
 ----
 
 Let's figure out how to get the bumper car to spin. To go straight, we
@@ -277,15 +277,15 @@ def BumperCar():
 
 	# Back up a bit and spin around
 	MoveOneDir()
-	time.sleep(1)
+	sleep(1)
 	SpinRandom()
 
 	MoveOneDir()
 	WaitUntilCloseOneDir()
 
 	# Back up a bit and spin around
 	MoveOtherDir()
-	time.sleep(1)
+	sleep(1)
 	SpinRandom()
 
 	MoveOtherDir()