# Exercise 4A
# Natural language translation.
#
# Author: David Watt.

# English-French dictionary ...
dictionary = {            \
    'a'      : 'un'     , \
    'the'    : 'la'     , \
    'is'     : 'est'    , \
    'she'    : 'elle'   , \
    'has'    : 'a'      , \
    'sees'   : 'voit'   , \
    'see'    : 'voyez'  , \
    'behold' : 'voila'  , \
    'of'     : 'de'     , \
    'my'     : 'ma'     , \
    'her'    : 'sa'     , \
    'pen'    : 'plume'  , \
    'aunt'   : 'tante'  , \
    'mother' : 'mere'   , \
    'child'  : 'enfant' }

def translate_word (word):
    "Return the translation of word using dictionary, \
     or '????' if word is not in dictionary."
    if word in dictionary.keys():
        return dictionary[word]
    else:
        return '????'

def translate_phrase (phrase1):
    "Return the translation of phrase1 using dictionary."
    len1 = len(phrase1)
    phrase2 = ''
    i = 0
    while i < len1:
        if phrase1[i].isalpha():
            start = i
            i += 1
            while i < len1 and phrase1[i].isalpha():
                i += 1
            word1 = phrase1[start:i]
            word2 = translate_word(word1)
            phrase2 += word2
        else:
            punct = phrase1[i]
            phrase2 += punct
            i += 1
    return phrase2

def translate (source_name, target_name):
    "Translate the contents of the file named source_name, \
     writing the result to the file named target_name."
    source_file = open(source_name, 'r')
    target_file = open(target_name, 'w')
    source_line = source_file.readline()
    while len(source_line) > 0:
        target_line = translate_phrase(source_line)
        target_file.write(target_line)
        source_line = source_file.readline()
    source_file.close()
    target_file.close()