Title: Processing a "locale" file with Python

Marking Scheme : The program works correctly with any valid file and for all options, but its execution experiences some minor problems.

In this assignment, you will write a Python program vaguely inspired by Unix command locale.Your Python program will parse a file containing information about language "locales" and "charmaps" and will generate output depending on the command line.

These are the specifications for your Python program:

$1.$ It must be named locale.py

$2.$ It should be invoked as:$$python locale.py option argument file

In the command line above, option means one of the options described below, and argument$\_$file means the chosen argument file, which can have any arbitrary name.

The program must check that argument argument$\_$file exists, is a file and is readable. If not, it must print an error message to the standard output and exit. The specifications for the argument$\_$file and option arguments are given below.

$3.$ File argument$\_$file can have any arbitrary name. It must be a file of text with the following format:

$*$ The file consists of an arbitrary number of lines $($including$,$ possibly, zero lines$).$

$*$ Each line must contain three fields separated by commas.

$*$ The three fields are: type, language, filename.

$*$ The type field can only have as value the literal strings locale or charmap.

$*$ The language and filename fields are each a string of characters of arbitrary $($yet reasonably limited$)$ length. Acceptable characters include: lower and upper case letters, digits, underscore, dot.

Fundamental note: your program is not expected to verify that file argument$\_$file complies with the above specifications. It will only be tested with compliant files.

The following example should be regarded as the reference specification for the format of file argument$\_$file:

locale, English, en $\_$AU

locale, French, fr$\_$BE

charmap, English, EN locale,

English, en$\_$US

charmap, Chinese, GBK

$4.$ Your program can be invoked with option: $-$a$.$ In this case, it must print the filenames of all the available locales, in this format:

Available locales:

filename of first locale in appearance order

filename of second locale in appearance order

$...$

filename of last locale in appearance order

Example with the example argument $\_$file given above:

Command line:

python locale.py $-$a argument$\_$file

Expected output:

Available locales:

en$\_$AU

fr$\_$BE

en$\_$US

In the case in which file argument$\_$file is empty or no available locales exist, your program must instead only print:

No locales available

$5.$ Your program can be invoked with option: $-$m$.$ In this case, it must print the filenames of all the available charmaps, in this format:

Available charmaps:

filename of first charmap in appearance order

filename of second charmap in appearance order

$...$

filename of last charmap in appearance order

Example with the example argument$\_$file given above:

Command line:

python locale.py $-$m argument$\_$file

Expected output:

Available charmaps:

EN

GBK

In the case in which file argument$\_$file is empty or no available charmaps exist, your program must instead only print:

No charmaps available

$6.$ Your program can be invoked with option: $-|$ language. The language argument has the same format as the language field in the argument file. In this case, your program must search for the language in the argument file, and if it finds it$,$ print the following information:

Language language:

Total number of locales: total number of locales in that language

$($possibly $0)$

Total number of charmaps: total number of charmaps in that language

$($possibly $0)$

Example with the example argument$\_$file given above:

Command line:

python locale.py $-1$ English argument$\_$file

Expected output:

Language English:

Total number of locales: $2$

Total number of charmaps: $1$

Another example with the example argument$\_$file given above:

Command line:

python locale.py $-1$ Chinese argument$\_$file

Expected output:

Language Chinese:

Total number of locales: $0$

Total number of charmaps: $1$

In the case in which language language is not present at all in argument$\_$file, your program must print:

No locales or charmaps in this language

Example with file argument$\_$file given above:

Command line:

python locale.py $-1$ German argument$\_$file

Expected output:

No locales or charmaps in this language

$7.$ Your program can be invoked with option: $-$v$.$ In this case, it must only print your name, surname, student ID and date of completion of your assignment, in a format of your choice. Please note that argument argument file is still required.

$8.$ No options can be used simultaneously. This means that your program can only be invoked with one of the options at a time.

$9.$ If your program is invoked with any other syntax than those specified above, it must print a message of your choice to the standard output and exit.

Examples of incorrect syntax:

python locale.py $-2$ argument$\_$file $($this option doesn't exist$)$

python locale.py $-$a $($it misses the arguement file$)$