getting rid of IDLE and other junk

Akuli · Akuli · commit 08885b2e9124 · 2017-02-28T21:55:59.000+02:00
diff --git a/basics/editor-setup.md b/basics/editor-setup.md
@@ -223,6 +223,9 @@ you need to keep in mind when reading the rest of this tutorial:
     but code in a file does nothing to the result. For example, typing
     `1 + 2` to the `>>>` prompt makes it echo `3`, but we need to do
     `print(1 + 2)` if we want to do the same thing in a file.
+- The editor doesn't replace the `>>>` prompt. The prompt is good for
+    trying things out quickly, and the editor is better when we want to
+    write longer programs.
 
 ## You're done!
 
diff --git a/basics/getting-started.md b/basics/getting-started.md
@@ -58,39 +58,11 @@ We didn't get an error... but `(3, 14)` is not at all what we expected!
 So from now on, let's use a dot with decimal numbers, because `3.14`
 worked just fine. Later we'll learn what `(3, 14)` is.
 
-What if we type a `#`?
-
-```python
->>> #
->>>
-```
-
-Nothing happened at all. Maybe we can type a `#` and then some text
-after it?
-
-```python
->>> # hello there
->>>
-```
-
-Again, nothing happened.
-
-If you're not using IDLE, the prompt will change from `>>>` to
-`...`. Just press Enter again to get it back to `>>>`.
-
-```python
->>> # hello again
-...
->>>
-```
-
-In Python, these pieces of text starting with a `#` are known as
-**comments**. They don't change how the code works in any way, but
-we can use them to explain what our code does.
-
 ## Using Python as a calculator
 
-Maybe we could type mathematical statements?
+**WARNING:** This part contains boring math. Be careful!
+
+Let's type some math stuff into Python and see what it does.
 
 ```python
 >>> 17 + 3
@@ -106,19 +78,22 @@ Maybe we could type mathematical statements?
 
 It's working, Python just calculates the result and echoes it back.
 
-The spaces between numbers and operators don't affect anything, they
-just make the code easier to read when they are used correctly.
+I added a space on both sides of `+`, `-`, `*` and `/`. Everything would
+work without those spaces too:
 
 ```python
->>> 14 + 2 + 1
-17
->>> 14            +2+ 1
-17
+>>> 4 + 2 + 1
+7
+>>> 4+2+1
+7
 >>>
 ```
 
-The evaluation order is similar to math. The parentheses `(` and `)`
-also work the same way.
+However, I recommend always adding the spaces because they make the code
+easier to read.
+
+Things are calculated in the same order as in math. The parentheses `(`
+and `)` also work the same way.
 
 ```python
 >>> 1 + 2 * 3        # 2 * 3 is calculated first
@@ -128,78 +103,33 @@ also work the same way.
 >>>
 ```
 
-Square brackets `[]` and curly brackets `{}` cannot be used to change
-the evaluation order. We'll learn more about what they do later.
+Python also supports many other kinds of calculations, but most of the
+time you don't need them. Actually you don't need even these
+calculations most of the time, but these calculations are probably
+enough when you need to calculate something.
 
-```python
->>> [1 + 2] * 3
-[3, 3, 3]
->>> {1 + 2} * 3
-Traceback (most recent call last):
-  File "<stdin>", line 1, in <module>
-TypeError: unsupported operand type(s) for *: 'set' and 'int'
->>>
-```
-
-## More advanced math
-
-I decided to include this in my tutorial because some people might be
-interested in this. Feel free to [skip this](#summary) if you're not
-interested.
+## Comments
 
-The `//` operator will divide and then throw away the dot and everything
-after it. For example, `17 / 3` is `5.666666666666667`, and so `17 // 3`
-is `5` because we throw away the `.666666666666667` part.
+We can also type a `#` and then whatever we want after that. These bits
+of text are known as **comments**, and we'll find uses for them later.
 
 ```python
->>> 17 / 3
-5.666666666666667
->>> 17 // 3
-5
+>>> 1 + 2     # can you guess what the result is?
+3
 >>>
 ```
 
-The `%` operator gets the division remainder.
+Again, I put a space after the `#` and multiple spaces before it just to
+make things easier to read.
 
-```python
->>> 17 % 3
-2
->>>
-```
-
-For example, if there were 17 apples that should be given evenly to 3
-people, everyone would get 5 apples and there would be 2 apples left
-over.
+If we write comment on a line with no code on it, the prompt changes
+from `>>>` to `...`. To be honest, I have no idea why it does that and I
+think it would be better if it would just stay as `>>>`. The prompt goes
+back to `>>>` when we press Enter again.
 
 ```python
->>> 17 // 3
-5
->>> 17 % 3
-2
->>>
-```
-
-This is also useful for converting time from minutes to seconds. 500
-seconds is 8 minutes and 20 seconds.
-
-```python
->>> 500 // 60
-8
->>> 500 % 60
-20
->>>
-```
-
-`**` can be used to raise to a power, so 3² in math is `3**2` in Python.
-Powers are calculated before `*` and `/`, but after `()`.
-
-```python
->>> 2 ** 3
-8
->>> 2 * 3 ** 2      # 3 ** 2 is calculated first
-18
->>> (2 * 3) ** 2    # 2 * 3 is calculated first
-36
+>>> # hello there
+...
 >>>
 ```
 
@@ -208,8 +138,8 @@ Powers are calculated before `*` and `/`, but after `()`.
 - Errors don't matter.
 - We can enter any Python commands to the interactive `>>>` prompt, and
     it will echo back the result.
-- Pieces of text starting with a `#` are comments.
 - `+`, `-`, `*` and `/` work in Python just like in math.
+- Pieces of text starting with a `#` are comments.
 
 ***
 
diff --git a/basics/if.md b/basics/if.md
@@ -40,19 +40,6 @@ An important thing to notice is that the line with a print is
 **indented**. You can press the tab key, or if it doesn't work
 just press space a few times.
 
-IDLE does this a bit differently, so if you use IDLE, running the
-example code looks more like this:
-
-```python
->>> its_raining = True
->>> if its_raining:
-        print("It's raining!")
-
-
-It's raining!
->>>
-```
-
 But why is that `if its_raining` instead of `if(its_raining)`?
 
 Earlier we learned that `if` is a **keyword**.
@@ -66,12 +53,12 @@ SyntaxError: invalid syntax
 >>>
 ```
 
-**Functions** like `print` need `()` after their name to work. But `if` is
-a keyword, not a function, so it doesn't need `()`. Python has separate
-functions and keywords because it's possible to create custom functions,
-but it's not possible to create custom keywords. That's why keywords are
-usually used for "magic" things that would be difficult to do with just
-functions.
+**Functions** like `print` need `()` after their name to work. But `if`
+is **a keyword**, not a function, so it doesn't need `()`. Python has
+separate functions and keywords because it's possible to create custom
+functions, but it's not possible to create custom keywords. That's why
+keywords are usually used for "magic" things that would be difficult to
+do with just functions.
 
 Also note that if statements check the condition once only, so if we
 set it to false later the if statement won't notice it.
@@ -86,62 +73,6 @@ It's not raining, but this runs anyway.
 >>>
 ```
 
-## Storing code in files
-
-At this point it's easier to put our code into a file and use it
-there. If you use IDLE, go to File at top left and select New File, or
-just press Ctrl+N.
-
-![New File in IDLE](../images/idle-new.png)
-
-If you don't use IDLE, please take the time to
-[set up your editor correctly](../editor-setup.md). When you're done your
-editor should give you four spaces every time you press tab.
-
-Create a file called `rain.py`, and type the following content into it:
-
-```python
-its_raining = True
-if its_raining:
-    print("It's raining!")
-```
-
-You can save the file anywhere you want, for example on your desktop.
-Give it a name that ends with `.py`, for example `rain.py`. The `.py`
-is short for Python.
-
-Now we can run the rain program. Most editors (including IDLE) will
-run our code when we press F5. If your editor doesn't, run it from
-PowerShell, command prompt or terminal. You probably need to first go
-to wherever you saved your file with `cd`. For example, if the file is
-on your desktop, type `cd Desktop` before running the file.
-
-Running from IDLE looks like this:
-
-    >>>
-    ========================= RESTART: /some/place/rain.py =========================
-    It's raining!
-    >>>
-
-And running from the Windows PowerShell or command prompt looks like
-this:
-
-    C:\Users\You> cd Desktop
-    C:\Users\You\Desktop> py rain.py
-    It's raining!
-    C:\Users\You\Desktop>
-
-Running from a terminal looks like this:
-
-    you@YourComputer:~$ cd Desktop
-    you@YourComputer:~/Desktop$ python3 rain.py
-    It's raining!
-    you@YourComputer:~/Desktop$
-
-From now on, **if a code example starts with `>>>` run it on the
-interactive prompt, and if it doesn't, write it to a file and run the
-file**.
-
 ## Using else
 
 What if we want to print a different message if it's not raining? We
@@ -157,6 +88,9 @@ if its_not_raining:
     print("It's not raining.")
 ```
 
+Note that this code example doesn't start with `>>>`, so you should
+[save it to a file and run the file](editor-setup.md).
+
 Now our program will print a different value depending on what the
 value of `its_raining` is.
 
@@ -208,19 +142,19 @@ else:
     print("Access denied.")
 ```
 
-The program prints different things depending on what we enter.
-
-    >>> ================================ RESTART ================================
-    >>>
-    Hello!
-    Enter your password: secret
-    Welcome!
-    >>> ================================ RESTART ================================
-    >>>
-    Hello!
-    Enter your password: lol
-    Access denied.
-    >>>
+The program prints different things depending on what we enter:
+
+```
+Hello!
+Enter your password: secret
+Welcome!
+```
+
+```
+Hello!
+Enter your password: lol
+Access denied.
+```
 
 Using the input function for passwords doesn't work very well because
 we can't hide the password with asterisks. There are better ways to get
diff --git a/basics/installing-python.md b/basics/installing-python.md
@@ -18,8 +18,7 @@ Let's get started!
 
 ### Windows
 
-Use the official Python installer, it will install Python and IDLE for
-you.
+Installing Python on Windows is a lot like installing any other program.
 
 1. Go to [the official Python website](https://www.python.org/).
 2. Move your mouse over the blue Downloads button, but don't click it.
diff --git a/basics/modules.md b/basics/modules.md
@@ -76,11 +76,13 @@ AttributeError: 'module' object has no attribute 'randint'
 
 But what was that? Why didn't it work?
 
+**TODO:** update the `-i` instructions.
+
 Let's go ahead and check what's wrong. If you don't use IDLE, you'll
 need to pass the `-i` option to Python, so if you would normally run
-`python3 random.py` you should now do `python3 -i random.py`. This
-will run the file and then give you a `>>>` prompt that we can use
-to check what's wrong. If you use IDLE, just run the file normally.
+`python3 random.py` you should now do `python3 -i random.py`. This will
+run the file and then give you a `>>>` prompt that we can use to check
+what's wrong. If you use IDLE, just run the file normally.
 
 We should end up with the same error message, and then a `>>>`.
 Like this:
@@ -211,12 +213,11 @@ The module name "sys" is short for "system", and it contains things
 that are built into Python. The official documentation is
 [here](https://docs.python.org/3/library/sys.html).
 
+`sys.stdin`, `sys.stdout` and `sys.stderr` are [file objects](files.md),
+just like the file objects that `open()` gives us.
+
 ```python
 >>> import sys
->>> # special files that the print and input functions use
->>> # stdin is short for standard input
->>> # stdout is short for standard output
->>> # stderr is short for standard errors
 >>> print("Hello!", file=sys.stdout)  # this is where prints go by default
 Hello!
 >>> print("Hello!", file=sys.stderr)  # use this for error messages
@@ -235,8 +236,7 @@ sys.version_info(major=3, minor=4, micro=2, releaselevel='final', serial=0)
 >>> sys.exit()  # exit out of Python
 ```
 
-If you use IDLE you'll notice that printing to `sys.stderr` makes
-the message show up in red instead of the normal blue.
+**TODO:** why stderr instead of stdout.
 
 `sys.exit()` does the same thing as `sys.exit(0)`. The zero means that
 the program succeeded, and everything's fine. If our program has an
@@ -251,9 +251,6 @@ if something_went_wrong:
     sys.exit(1)
 ```
 
-`sys.exit` doesn't work for getting out of IDLE's `>>>` prompt. You can
-just close the window to get out of IDLE.
-
 ### Mathematics
 
 There's no math.py anywhere, math is a built-in module like
diff --git a/basics/using-functions.md b/basics/using-functions.md
