Assignment 8

Question 1

Given that Imperial and Metric units are still used in different countries, it is often necessary to convert from a measure in one unit to a measure in another, e.g.,
• Given x feet, to convert to metres, multiply x by 0.305;
• Given x metres, to convert to feet, multiply x by 3.28;
• Given x pounds, to convert to kilos, multiply x by 0.454; and
• Given x kilos, to convert to pounds, multiply x by 2.202.

Write and document a Python script convert2.py which takes as command-line arguments a given-unit type in {Metric, Imperial} and an input textfile, and outputs the version of the input textfile in which all units that are the opposite unit-type of that specified are translated into the units of the specified type as described above. Note that unit-quantities may be specified in the given text using either integers or floating-point numbers. The conversion mechanism must be implemented using functions from the re module. Your script must work on datafile convert2.txt to produce the output given in typescript-file convert2.script.

Question 2

A reversible translator between two dialects of the same language can be specified by i) a set of mapping rules of the form "X" <=> "Y" indicating that text X in dialect #1 maps onto text Y in dialect #2 and vice versa, and ii) a mechanism that applies (i) to a piece of text from dialect #1 (#2) to create the corresponding piece of text in dialect #2 (#1). The rules in (i) are stored in a dialect translation file which may contain embedded (and ignored) comments. The mechanism in (ii) applies the rules in (i) in the order in which they are specified to a sentence of the given dialect. As text in one dialect may be longer or shorter than the corresponding text in the other dialect and we want to maintain the approximate line-length of the original text, the mechanism in (ii) should also make sure that it adjusts the translated text such that no line is longer than the longest line in the given text.

Write and document a Python script rtrans.py which, given a dialect translation file, a translation-direction string "to" or "from", and a dialect textfile as command-line arguments, prints a line-length adjusted version of the given text as translated relative to the given translation file in either the forward or backward direction, respectively. The translation mechanism must be implemented using functions from the re module. Your script must work on dialect-translation files e2g1.txt and e2g2.txt and textfile rtrans.txt to produce the output given in typescript-file rtrans.script. You may assume that all dialect translation files are valid.

Hints

In Question 1, you may find it useful to process recognized quantity-unit pairs using lambda functions for the replacement patterns in the sub() function.

In Question 2, you may find it useful to recognize and parse the rules in a dialect translation file using the regular-expression matching functions in re before applying this rule-set (again using re functions) to the provided text.

Submission

Please hand in printed copies of all of your Python script files. You must also submit these files electronically using the submit-assignment command. Note that each script file must have the following comment block at the top, where the X's are replaced with the appropriate information, followed by a docstring briefly describing the program in that script. For instance, my script for this assignment would begin with the following comment block:

#########################################################
##  CS 2500 (Fall 2010), Assignment #8, Question #1    ##
##   Script File Name: convert2.py                     ##
##       Student Name: Todd Wareham                    ##
##         Login Name: harold                          ##
##              MUN #: 8008765                         ##
#########################################################

You do not have to develop your code on our CS departmental systems. However, as your code will be compiled and tested on our CS departmental systems as part of the assignment marking process, you should ensure that your code compiles and runs correctly on at least one of these systems.

Additional Notes:

• Oct 7, 9:35am
  Assignment #8 posted.

Created: October 7, 2010
Last Modified: October 20, 2010