Move to Print functions

This is the main visual difference in Python 3. These are all still
valid in Python 2, though hopefully we won't go back there.

I've left in place the terminology of "print statements" because:
a) it's teechnically still correct -- `print(x)` _is_ a statement
b) this is easy to change later (at no additional effort) if we
   decide we really want to
c) I think "print statement" sounds nicer than "print funtion call"

Author: PeterJCLaw

IDE/code_checking.md

@@ -32,7 +32,7 @@ So an error on the second line of a file,
 
 ~~~~~ python
 import sr.robot
-print bacon
+print(bacon)
 ~~~~~
 
 Would show up as:

programming/python/functions.md

@@ -22,7 +22,7 @@ This would be used by some other code as follows:
 
 ~~~~~ python
 sq = square(5)
-print sq  # prints: 25
+print(sq)  # prints: 25
 ~~~~~
 
 Another advantage of grouping your code like this is that if you decide you change the way that it works slightly,
@@ -33,6 +33,6 @@ The same function modified & printing a log message:
 
 ~~~~~ python
 def square(num):
-    print "found the square of {:d}".format(num)
+    print("found the square of {:d}".format(num))
     return num * num
 ~~~~~

programming/sr/index.md

@@ -79,10 +79,10 @@ usbkey
     import os
 
     R = Robot()
-    print "The path to the USB key is:", R.usbkey
-    print "My file on the USB contains:"
+    print("The path to the USB key is:", R.usbkey)
+    print("My file on the USB contains:")
     with open(os.path.join(R.usbkey, 'my-file.txt'), 'r') as f:
-        print f.read()
+        print(f.read())
     ~~~~~
 
 [Custom Robot Object Initialisation](#CustomRobotInit) {#CustomRobotInit}

programming/sr/power/index.md

@@ -21,7 +21,7 @@ You can access these values like so:
 
 ~~~~~ python
 # Print the battery voltage and current to the log
-print R.power.battery.voltage, R.power.battery.current
+print(R.power.battery.voltage, R.power.battery.current)
 ~~~~~
 
 A fully charged battery will measure 12.6V.

programming/sr/vision/index.md

@@ -36,11 +36,11 @@ R = Robot()
 
 while True:
     markers = R.see()
-    print "I can see", len(markers), "markers:"
+    print("I can see", len(markers), "markers:")
 
     for m in markers:
         if m.info.marker_type == MARKER_ARENA:
-            print " - Marker #{0} is {1} metres away".format(m.info.code, m.dist)
+            print(" - Marker #{0} is {1} metres away".format(m.info.code, m.dist))
 ~~~~~
 
 [Choosing Resolution](#ChoosingResolution) {#ChoosingResolution}
@@ -217,9 +217,9 @@ polar
     For example, the following code displays the polar coordinate of a `Point` object `p`:
 
     ~~~~~ python
-    print "length", p.polar.length
-    print "rot_x", p.polar.rot_x
-    print "rot_y", p.polar.rot_y
+    print("length", p.polar.length)
+    print("rot_x", p.polar.rot_x)
+    print("rot_y", p.polar.rot_y)
     ~~~~~
 
 [`Orientation`](#Orientation) {#Orientation}

troubleshooting/python.md

@@ -21,7 +21,7 @@ For example:
 
 ~~~~~ python
 def foo(s):
-	print s
+	print(s)
 
 foo "Hello World!"  # should be foo("Hello World!")
 ~~~~~
@@ -51,7 +51,7 @@ Other causes of syntax errors to look out for are:
 
 ~~~~~ python
 x = 5
-print X     # wrong case
+print(X)     # wrong case
 ~~~~~
 
 Error:
@@ -75,8 +75,8 @@ For example:
 
 ~~~~~ python
 a = ["Molly", "Polly", "Dolly"]
-print a[0]
-print a[3]
+print(a[0])
+print(a[3])
 ~~~~~
 
 Error:

tutorials/basic_motor_control.md

@@ -223,7 +223,7 @@ Here's an example:
 
 ~~~~~ python
 for i in [1, 2, 3]:
-	print i
+	print(i)
 ~~~~~
 
 The above would output: