[Webware-discuss] Fwd: Re: ASP & Python indentation

[Chuck E. <ec...@mi...>]

A reply just came in to my earlier ASP question, but was not CCed to the 
list. Here it is:


>From: "Tom Funk" <td...@td...>
>To: "Chuck Esterbrook" <ec...@mi...>
>Subject: Re: ASP & Python indentation
>Date: Tue, 30 May 2000 07:02:45 -0400
>X-Mailer: Microsoft Outlook Express 5.00.2919.6600
>
>Hi,Chuck,
>
>First, please let me apologize for taking so long to respond -- I've been
>installing a new machine at home and it's been fighting me.  I'm finally
>back online.
>
>Now on to the meat of your question.
>
>My experience with indentation when using Python as the ASP scripting
>language has come from using Win32.  Also, all of the following is from
>memory, as I've been away from Python and ASP for a couple of months now.
>
>Under Win32, ASP Python follows the same rules as for "regular" Python.
>Iow, *all* indentation is significant.
>
> >> The following cases are especially interesting:
> >> > * When the contents of the loop go back and forth between HTML and
>Python statements wrapped in <% %>
>
>I've found it best not to use inline constructs like this:
>
>...
>     <td>The value is <% string.lower("ABC") %></td>
>...
>
>The interpreter remembers the indentation from any previous Python code and
>complains if the new code is indented incorrectly.  In a "<%=" construct, I
>think the interpreter starts counting spaces after the "=", so, if you have
>the wrong number of spaces between your Python expression and the "=", the
>interpreter will get sick. Also, when you follow "<%" with one or more
>Python expressions, I belive the  interpreter starts counting spaces after
>the "%".  So, the first character is at the left margin, the next is the
>second character, etc.  I suppose you could keep the indentaion consistent
>by adding the correct number of spaces or tabs afterthe "%".  I'd think this
>would be tedious, though.
>
>For most of my Python ASP I inserted the "<%" at the left margin, added a
>line break and then started the Python code on the left margin, like this:
>
>...
>     <td>The value is
><%
>string.lower("ABC")
>%>
>    </td>
>...
>
>This sometimes shoots your careful HTML indentation out of the water, but it
>keeps the Python interpreter happy.
>
>If you're using a loop construct, you can do that like this:
>
>...
><%
>for i in range(10):
>     if i % 2 == 0:
>         Response.Write("<br>%d is even\n" % (i))
>     else:
>         Response.Write("<br>%d is odd\n" % (i))
>%>
>
>At first I was tempted to use "<%=" and mix it with HTML text, but that got
>confusing.  After the two previous indentations (first for the "for" and
>next for the "if"), when the interpreter encounters something like:
>
><%
>for i in range(10):
>     if i % 2 == 0:
>%>
>         <br><%=i%> is even
><%
>     else:
>%>
>         <br><%=i%> is odd
>
>The interpreter gets upset.  In this case, the "i" after the "<%=" is not
>indented (it's right up against the <%=), so it looks to the interpreter as
>though the "i" is sitting at the left margin.  Since the interpreter was
>expecting to see some code after the "if" statement, you'll get a syntax
>error for invalid indentation. If you insert a space after the "<%=" for
>readability, as I often do, this looks like you've indented by a single
>space.  If this is inconsistent with the expected indentation, the
>interpreter will complain.
>
> >> > * When loops are nested
>
>Nested loops would be the same way:
>...
><table>
><th colspan="10">Numbers from 0 to 99, in a 10x10 matrix</th>
><%
># start on the left margin
>for i in range(10):
>     Response.Write("<tr>\n)
>     # notice the indentation is continued from above
>     for j in range(10):
>         Response.Write("<td>%d</td>" % ((i * 10) + j)
>     Response.Write("\n</tr>\n)
>%>
></table>
>...
>
>If you tried to use the "<%=" construct, you'd again get an error because
>the indentation is inconsistent.  You *can* use the "<%=" construct, but I
>think you'd have to follow the equals sign with the approprate number of
>spaces/tabs for the indentation to be consistent.  Count wrong and you'll
>get an error.
>
>I also tend to use spaces (either two or three spaces per indentation)
>instead of tabs and I count them very deliberately.  Also, as much as
>possible I use function calls whereever I can and define my functions and
>classes at the top of the page.  The previous example could be rewritten as:
>
><%@Language=Python%>
><%
># again, start on the left margin
>def printMatrix(rows, cols):
>     Response.Write("<table>\n")
>     Response.Write("""<th colspan="%d">Numbers from 0 to %d, in a %dx%d
>matrix</th>\n""" % \
>                              (cols, (rows * cols) - 1, rows, cols)
>     for i in range(rows):
>         Response.Write("<tr>\n)
>         for j in range(cols):
>             Response.Write("<td>%d</td>" % ((i * cols) + j)
>         Response.Write("\n</tr>\n)
>%>
>... ... <% # start back at he margin printMatrix(10,10) %> Of course, you 
>can use the entire Python language, including creating classes and invoke 
>methods on those classes to execute your logic. The sky's the limit. I 
>know this was long, but I hope it helps. -=< tom >=- ----- Original 
>Message ----- From: "Chuck Esterbrook" To: ; Cc: Sent: Wednesday, May 24, 
>2000 12:30 PM Subject: ASP & Python indentation > Hi, > > After searching 
>usenet on deja.com, I found that both of you are successfully running 
>Python in Microsoft's ASP. > > My group is struggling with indentation 
>issues/policies for our PSP (Python Server Pages) subproject which could 
>be considered an alternative to ASP. > > Could you point us to a resource 
>that explains more about using Python in MS ASP, and/or show us examples 
>of how indentation works? The following cases are especially 
>interesting: > * When the contents of the loop go back and forth between 
>HTML and Python statements wrapped in <% %> > * When loops are nested > > 
>If you like, you can learn more about our project at: 
>http://webware.sourceforge.net > > Any help is appreciated in 
>advance! > > > -Chuck > >