Task 1. Case Mapping

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Available Marks: 7

Perl's regular expressions have been adopted by other systems, sometimes incompletely. Version 9.1 of the SAS enterprise database system, for example, didn't implement case mapping codes in replacement text. This task does so, but for any string.

Embedded in a string of printable ASCII characters are the following symbol sequences, that change the state of the characters that follow:

Code	State change
`\u`	The following single character is converted to upper case
`\l`	The following single character is converted to lower case
`\U`	All following characters are converted to upper case
`\L`	All following characters are converted to lower case
`\E`	Stop converting case

Rules

Only letters can be changed, so \u# or \L123\E do not alter the # or 123.
\u and \l can be nested inside \L and \U, so \Um\lcdonald\E becomes McDONALD.
\U or \L terminate any previous \U or \L without the need for \E.
All code sequences are removed from the result, including redundant ones such as repeated \E, \U or \L, or \u nested inside \U etc.
There are no error cases, backslash followed by any character other than those above is uninterpreted.

Write a program that reads a file of lines representing perl-style case mapping strings, preceded by the number of lines, and displays the converted lines. There can be up to 20 lines and each line can have up to 100 characters.

Example

Input:

3
\Uunsw\E Computing
\uprogcomp \l2013\u.
T\LITLE CASE\E is also known as \L\uproper CASE\E.

Output:

UNSW Computing
Progcomp 2013.
Title case is also known as Proper case.

Test Data

You should test your program on the following data:

9
Mapping "\UuPpEr"\E and "\LlOWeR\E" case
\uNon-\lNested \using\lles
Nested \L\umc\uvEE\E and \Uo'l\le\la\lr\ly\E, \U\lR\Eedundant sequences.
Nested same-case: \Uab\uc\ud\uef\E and \L\lAB\lC\lDE\lF\E
Punctuation is unaffected\U:!@#$%^&*()_-+={}[]'";:,.<>/?1234567890\E
To get a \u\ precede it with either \l\u or \u\l.
\u\E is optional and can be redundant\E\E\E: \u\Uh\u\LeLLo[endofline] produces \Uh\LeLLo
Pointless repeats: \L\L\L\L\L\L\L\L\U\L\L\L\L\U\U\U\L\L\L\LX\E
Non-special sequences \t \n \e \A \$ \\

#-------------------------------------------------------------------------------

# Name: Task 1. Case Mapping

# Purpose:

# Author: Joseph.Lai

# Created: 22/05/2014

# Copyright: (c) Joseph.Lai 2014

# Licence: <your licence>

#-------------------------------------------------------------------------------

# List here instead of File Read for Testing purposes

list1 = [

r"\Uunsw\E Computing",

r"\uprogcomp \l2013\u.",

r"T\LITLE CASE\E is also known as \L\uproper CASE\E",

]

def doGetFile():

# Here is where you enter code to read from a file. This has been done before in other examples

# Choose the list to process - list1 is the test, list2 is actual data

#return list1

# Open a file

fileName = "Input Task1 Case Mapping.txt"

fo = open(fileName, "r")

file=fo.read();

fo.close();

inp = file.splitlines(); # creates a list from the file input separated by \n (default)

return inp

def doProcess(sentence):

i = -1

newSentence = ""

control = False

upperLetter = False

upperWord = False

lowerLetter = False

lowerWord = False

while i < len(sentence)-1:

i +=1

# Determine if Control Characters

if sentence[i] == "\\":

control=True

elif control:

if sentence[i] == "U":

upperWord = True

lowerWord = False

elif sentence[i] == "L":

lowerWord = True

upperWord = False

#print("{} {}".format(lowerWord,upperWord),end =' ')

elif sentence[i] == "u":

upperLetter = True

elif sentence[i] == "l":

lowerLetter = True

elif sentence[i] == "E":

upperLetter = False

upperWord = False

lowerLetter = False

lowerWord = False

control = False

else:

# Normal letter

#print(sentence[i],end= ' ')

if upperLetter:

if sentence[i].isalpha(): #only change case if Alphabetic

newSentence = newSentence + sentence[i].upper()

else: