From 024a387f89cd4c08b67ffca0d8df311a34cc8a49 Mon Sep 17 00:00:00 2001 From: Jack Jansen Date: Thu, 18 Jul 1996 16:07:05 +0000 Subject: - Added a file dialog example - Added pointers to library documentation --- Mac/Demo/example0.html | 75 ++++++++++++++++++++++++++++++++++++++++++ Mac/Demo/example0/checktext.py | 39 ++++++++++++++++++++++ Mac/Demo/index.html | 15 ++++++++- Mac/Demo/using.html | 5 ++- 4 files changed, 132 insertions(+), 2 deletions(-) create mode 100644 Mac/Demo/example0.html create mode 100644 Mac/Demo/example0/checktext.py diff --git a/Mac/Demo/example0.html b/Mac/Demo/example0.html new file mode 100644 index 0000000..c0336a5 --- /dev/null +++ b/Mac/Demo/example0.html @@ -0,0 +1,75 @@ +Using python to create Macintosh applications, part zero + +

Using python to create Macintosh applications, part zero

+
+ +This document will show you how to create a simple mac-style +application using Python. We will glance at how to use file dialogs and +messages.

+ +Our example program checktext.py asks +the user for a text file and checks what style end-of-lines the file has. +This may need a little explanation: ASCII text files are almost identical +on different machines, with one exception: +

+ +Let us have a look at the program. The first interesting statement in the main +program is the call to macfs.PromptGetFile. This is one of the routines +that allow you to ask the user to specify a file. You pass it one required +argument, the prompt string. There are up to four optional MacOS file type arguments +you can pass, as 4-byte strings. Specifying no file +type will allow the user to select any file, specifying one or more types restricts +the user to files of this type. File types are explained in most books on the Mac.

+ +PromptGetFile returns two values: an FSSpec object and a +success indicator. The FSSpec object is the "official" MacOS way of specifying a +file, more on it later. The success indicator tells you whether the user clicked OK +or Cancel. In the event of Cancel we simply exit back to the finder.

+ +PromptGetFile has a number of friends that do similar things: +

+All routines return an FSSpec and a success indicator.

+ +There are many things you can do with FSSpec objects (see the +macfs section in the +Python Library Reference +for details), but passing them to open is not +one of them. For this, we first have to convert the FSSpec object to a pathname, with +the as_pathname method. This returns a standard MacOS-style pathname with +colon-separated components. This can then be passed to open. Note that +we call open with mode parameter 'rb': we want to read the file in binary +mode. Python, like C and C++, uses unix-style line endings internally and opening a +file in text mode ('r') would result in conversion of carriage-returns to +linefeeds upon reading. This is something that Mac and DOS programmers are usually aware +of but that never ceases to amaze unix buffs.

+ +After we open the file we attempt to read all data into memory. If this fails we use +EasyDialogs.Message to display a message in a standard dialog box and exit. +The EasyDialogs module has a few more useful simple dialog routines, more on that in +example 1.

+ +The rest of the code is pretty straightforward: we check that the file actually contains +data, count the number of linefeeds and returns and display a message with our guess of the +end-of-line convention used in the file.

+ +The example0 folder has three text files in Mac, Unix and DOS style +for you to try the program on. After that, you can continue with example 1 +or go back to the index to find another interesting topic.

+ +

+Jack Jansen, +jack@cwi.nl, 18-July-1996. + diff --git a/Mac/Demo/example0/checktext.py b/Mac/Demo/example0/checktext.py new file mode 100644 index 0000000..93a814d --- /dev/null +++ b/Mac/Demo/example0/checktext.py @@ -0,0 +1,39 @@ +"""checktext - Check that a text file has macintosh-style newlines""" + +import macfs +import sys +import EasyDialogs +import string + +def main(): + fsspec, ok = macfs.PromptGetFile('File to check end-of-lines in:', 'TEXT') + if not ok: + sys.exit(0) + pathname = fsspec.as_pathname() + fp = open(pathname, 'rb') + try: + data = fp.read() + except MemoryError: + EasyDialogs.Message('Sorry, file is too big.') + sys.exit(0) + if len(data) == 0: + EasyDialogs.Message('File is empty.') + sys.exit(0) + number_cr = string.count(data, '\r') + number_lf = string.count(data, '\n') + if number_cr == number_lf == 0: + EasyDialogs.Message('File contains no lines.') + if number_cr == 0: + EasyDialogs.Message('File has unix-style line endings') + elif number_lf == 0: + EasyDialogs.Message('File has mac-style line endings') + elif number_cr == number_lf: + EasyDialogs.Message('File probably has MSDOS-style line endings') + else: + EasyDialogs.Message('File has no recognizable line endings (binary file?)') + sys.exit(0) + +if __name__ == '__main__': + main() + + diff --git a/Mac/Demo/index.html b/Mac/Demo/index.html index 8d691f4..57b28fd 100644 --- a/Mac/Demo/index.html +++ b/Mac/Demo/index.html @@ -19,6 +19,12 @@ HREF="http://www-acs.ucsd.edu/~jstrout/python/"> http://www-acs.ucsd.edu/~jstrout/python/.

+The Python Library Reference contains a section on +Macintosh-specific modules +that you should also read. Documentation is also available in PostScript and other +forms, see the documentation section +on the webserver.

+ Some of these documents were actually written while I was working on a "real" project: creating a single-button application that will allow my girlfriend to read her mail (which actually pass thry my @@ -37,6 +43,12 @@ with earlier versions of Python, some will definitely not.