Grammalecte  Changes On Branch f7c9ad046c8c4f56

                        echo("* " + sWord)
                        for sMorph in oDict.getMorph(sWord):
                            echo("  {:<32} {}".format(sMorph, oLexGraphe.formatTags(sMorph)))
            elif sText.startswith("!"):
                for sWord in sText[1:].strip().split():
                    if sWord:
                        echo(" | ".join(oDict.suggest(sWord)))
                        #echo(" | ".join(oDict.suggest2(sWord)))
            elif sText.startswith(">"):
                oDict.drawPath(sText[1:].strip())
            elif sText.startswith("="):
                for sRes in oDict.select(sText[1:].strip()):
                    echo(sRes)
            elif sText.startswith("/+ "):
                gce.setOptions({ opt:True  for opt in sText[3:].strip().split()  if opt in gce.getOptions() })

    'œ': 'oe',  'æ': 'ae', 
})

def cleanWord (sWord):
    "word simplication before calculating distance between words"
    return sWord.lower().translate(_xTransChars).replace("eau", "o").replace("au", "o")


def distanceDamerauLevenshtein (s1, s2):
    "distance of Damerau-Levenshtein between <s1> and <s2>"
    # https://fr.wikipedia.org/wiki/Distance_de_Damerau-Levenshtein
    d = {}
    nLen1 = len(s1)
    nLen2 = len(s2)
    for i in range(-1, nLen1+1):
        d[i, -1] = i + 1
    for j in range(-1, nLen2+1):
        d[-1, j] = j + 1
    for i in range(nLen1):
        for j in range(nLen2):
            nCost = 0  if s1[i] == s2[j]  else 1
            d[i, j] = min(
                d[i-1, j]   + 1,        # Deletion
                d[i,   j-1] + 1,        # Insertion
                d[i-1, j-1] + nCost,    # Substitution
            )
            if i and j and s1[i] == s2[j-1] and s1[i-1] == s2[j]:
                d[i, j] = min(d[i, j], d[i-2, j-2] + nCost)     # Transposition
    return d[nLen1-1, nLen2-1]


def showDistance (s1, s2):
    s1b = cleanWord(s1);
    s2b = cleanWord(s2);
    print(f"Distance: {s1} / {s2} = {distanceDamerauLevenshtein(s1, s2)}")
    print(f"Distance: {s1b} / {s2b} = {distanceDamerauLevenshtein(s1b, s2b)}")


# Method: Remove Useless Chars

_dVovels = {
    'a': '',  'e': '',  'i': '',  'o': '',  'u': '',  'y': '',
    'à': '',  'é': '',  'î': '',  'ô': '',  'û': '',  'ÿ': '',
    'â': '',  'è': '',  'ï': '',  'ö': '',  'ù': '',  'ŷ': '',
    'ä': '',  'ê': '',  'í': '',  'ó': '',  'ü': '',  'ý': '',
    'á': '',  'ë': '',  'ì': '',  'ò': '',  'ú': '',  'ỳ': '',
    'ā': '',  'ē': '',  'ī': '',  'ō': '',  'ū': '',  'ȳ': '',
    'h': '',  'œ': '',  'æ': ''
 }

_xTransVovels = str.maketrans(_dVovels)


aVovels = frozenset(_dVovels.keys())


def shrinkWord (sWord):
    "remove vovels and h"
    return sWord[0:1].replace("h", "") + sWord[1:].translate(_xTransVovels)


# Similar chars

d1to1 = {
    "1": "liîLIÎ",
    "2": "zZ",
    "3": "eéèêEÉÈÊ",

#!python3

import os
import traceback
import pkgutil
import re
from itertools import chain
from functools import wraps
import time

#import logging
#logging.basicConfig(filename="suggestions.log", level=logging.DEBUG)
import logging
logging.basicConfig(filename="suggestions.log", level=logging.DEBUG)

from . import str_transform as st
from . import char_player as cp
from .echo import echo


def timethis (func):
    "decorator for the execution time"
    @wraps(func)
    def wrapper (*args, **kwargs):
        fStart = time.time()
        result = func(*args, **kwargs)
        fEnd = time.time()
        print(func.__name__, fEnd - fStart)
        return result
    return wrapper


class SuggResult:
    """Structure for storing, classifying and filtering suggestions"""

    def __init__ (self, sWord, nDistLimit=-1):
        self.sWord = sWord
        self.sCleanWord = cp.cleanWord(sWord)
        self.nDistLimit = nDistLimit  if nDistLimit >= 0  else  (len(sWord) // 3) + 1
        self.nMinDist = 1000
        self.aSugg = set()
        self.dSugg = { 0: [],  1: [] }

    def addSugg (self, sSugg, nDeep=0):
        "add a suggestion"
        #logging.info((nDeep * "  ") + "__" + sSugg + "__")
        if sSugg not in self.aSugg:
            nDist = st.distanceDamerauLevenshtein(self.sCleanWord, cp.cleanWord(sSugg))
            if nDist <= self.nDistLimit:
                if nDist not in self.dSugg:
                    self.dSugg[nDist] = []
                self.dSugg[nDist].append(sSugg)
                self.aSugg.add(sSugg)
                if nDist < self.nMinDist:
                    self.nMinDist = nDist
                self.nDistLimit = min(self.nDistLimit, self.nMinDist+2)

    def getSuggestions (self, nSuggLimit=10, nDistLimit=-1):
        "return a list of suggestions"
        lRes = []
        if self.dSugg[0]:
            # we sort the better results with the original word
            self.dSugg[0].sort(key=lambda sSugg: st.distanceDamerauLevenshtein(self.sWord, sSugg))
        for lSugg in self.dSugg.values():
            lRes.extend(lSugg)
            if len(lRes) > nSuggLimit:
                break
        lRes = list(cp.filterSugg(lRes))
        if self.sWord.istitle():
            lRes = list(map(lambda sSugg: sSugg.title(), lRes))
        elif self.sWord.isupper():
            lRes = list(map(lambda sSugg: sSugg.upper(), lRes))
        return lRes[:nSuggLimit]

    def reset (self):
        self.aSugg.clear()
        self.dSugg.clear()


class IBDAWG:
    """INDEXABLE BINARY DIRECT ACYCLIC WORD GRAPH"""

    def __init__ (self, sDicName):
        self.by = pkgutil.get_data(__package__, "_dictionaries/" + sDicName)
        if not self.by:

                l.extend(self.morph(sWord.capitalize()))
        return l

    @timethis
    def suggest (self, sWord, nMaxSugg=10):
        "returns a set of suggestions for <sWord>"
        sPfx, sWord, sSfx = cp.cut(sWord)
        nMaxSwitch = max(len(sWord) // 3, 1)
        nMaxDel = len(sWord) // 5
        nMaxHardRepl = max((len(sWord) - 5) // 4, 1)
        oSuggResult = SuggResult(sWord)
        aSugg = self._suggest(sWord, nMaxDel=nMaxDel, nMaxHardRepl=nMaxHardRepl)
        self._suggest(oSuggResult, sWord, nMaxSwitch=nMaxSwitch, nMaxDel=nMaxDel, nMaxHardRepl=nMaxHardRepl)
        if sWord.istitle():
            aSugg.update(self._suggest(sWord.lower(), nMaxDel=nMaxDel, nMaxHardRepl=nMaxHardRepl))
            self._suggest(oSuggResult, sWord.lower(), nMaxSwitch=nMaxSwitch, nMaxDel=nMaxDel, nMaxHardRepl=nMaxHardRepl)
            aSugg = set(map(lambda sSugg: sSugg.title(), aSugg))
        elif sWord.islower():
            aSugg.update(self._suggest(sWord.title(), nMaxDel=nMaxDel, nMaxHardRepl=nMaxHardRepl))
        aSugg = cp.filterSugg(aSugg)
        sCleanWord = cp.cleanWord(sWord)
        aSugg = sorted(aSugg, key=lambda sSugg: cp.distanceDamerauLevenshtein(sCleanWord, cp.cleanWord(sSugg)))[:nMaxSugg]
            self._suggest(oSuggResult, sWord.title(), nMaxSwitch=nMaxSwitch, nMaxDel=nMaxDel, nMaxHardRepl=nMaxHardRepl)
        aSugg = oSuggResult.getSuggestions()
        if sSfx or sPfx:
            # we add what we removed
            return list(map(lambda sSug: sPfx + sSug + sSfx, aSugg))
        return aSugg

    def _suggest (self, oSuggResult, sRemain, nMaxSwitch=0, nMaxDel=0, nMaxHardRepl=0, nDeep=0, iAddr=0, sNewWord="", sAction="", bAvoidLoop=False):
        # recursive function
        #logging.info((nDeep * "  ") + sNewWord + ":" + sRemain + " · " + sAction)
        if not sRemain:
            if int.from_bytes(self.byDic[iAddr:iAddr+self.nBytesArc], byteorder='big') & self._finalNodeMask:
                oSuggResult.addSugg(sNewWord, nDeep)
            for sTail in self._getTails(iAddr):
                oSuggResult.addSugg(sNewWord+sTail, nDeep)
            return
        cCurrent = sRemain[0:1]
        for cChar, jAddr in self._getSimilarCharArcs(cCurrent, iAddr):
            self._suggest(oSuggResult, sRemain[1:], nMaxSwitch, nMaxDel, nMaxHardRepl, nDeep+1, jAddr, sNewWord+cChar, "*")
        if not bAvoidLoop: # avoid infinite loop
            if len(sRemain) > 1:
                if cCurrent == sRemain[1:2]:
                    # same char, we remove 1 char without adding 1 to <sNewWord>
                    self._suggest(oSuggResult, sRemain[1:], nMaxSwitch, nMaxDel, nMaxHardRepl, nDeep+1, iAddr, sNewWord, cCurrent+"/2")
                else:
                    # switching chars
                    if nMaxSwitch:
                        self._suggest(oSuggResult, sRemain[1:2]+sRemain[0:1]+sRemain[2:], nMaxSwitch-1, nMaxDel, nMaxHardRepl, nDeep+1, iAddr, sNewWord, "><",True)
                    # delete char
                    if nMaxDel:
                        self._suggest(oSuggResult, sRemain[1:], nMaxSwitch, nMaxDel-1, nMaxHardRepl, nDeep+1, iAddr, sNewWord, "-"+cCurrent, True)
                # Phonetic replacements
                for sRepl in cp.d1toX.get(cCurrent, ()):
                    self._suggest(oSuggResult, sRepl + sRemain[1:], nMaxSwitch, nMaxDel, nMaxHardRepl, nDeep+1, iAddr, sNewWord, cCurrent+">"+sRepl, True)
                for sRepl in cp.d2toX.get(sRemain[0:2], ()):
                    self._suggest(oSuggResult, sRepl + sRemain[2:], nMaxSwitch, nMaxDel, nMaxHardRepl, nDeep+1, iAddr, sNewWord, sRemain[0:2]+">"+sRepl, True)
                # Hard replacements
                if nDeep > 3 and nMaxHardRepl:
                    for cChar, kAddr in self._getCharArcs(iAddr):
                        if cChar not in cp.d1to1.get(cCurrent, ""):
                            self._suggest(oSuggResult, sRemain[1:], nMaxSwitch, nMaxDel, nMaxHardRepl-1, nDeep+1, kAddr, sNewWord+cChar, "[["+cChar+"]]", True)
            # end of word
            if len(sRemain) == 2:
                for sRepl in cp.dFinal2.get(sRemain, ()):
                    self._suggest(oSuggResult, sRepl, nMaxSwitch, nMaxDel, nMaxHardRepl, nDeep+1, iAddr, sNewWord, sRemain + " >> " + sRepl, True)
            elif len(sRemain) == 1:
                self._suggest(oSuggResult, "", nMaxSwitch, nMaxDel, nMaxHardRepl, nDeep+1, iAddr, sNewWord, sRemain + " [last char removed] ", True) # remove last char and go o
                for sRepl in cp.dFinal1.get(sRemain, ()):
                    self._suggest(oSuggResult, sRepl, nMaxSwitch, nMaxDel, nMaxHardRepl, nDeep+1, iAddr, sNewWord, sRemain + " >> " + sRepl, True)
        return

    @timethis
    def suggest2 (self, sWord, nMaxSugg=10):
        "returns a set of suggestions for <sWord>"
        sPfx, sWord, sSfx = cp.cut(sWord)
        oSuggResult = SuggResult(sWord)
        self._suggest2(oSuggResult)
        aSugg = oSuggResult.getSuggestions()
        if sSfx or sPfx:
            # we add what we removed
            return list(map(lambda sSug: sPfx + sSug + sSfx, aSugg))
        return aSugg

    def _suggest (self, sRemain, nMaxDel=0, nMaxHardRepl=0, nDeep=0, iAddr=0, sNewWord="", bAvoidLoop=False):
    def _suggest2 (self, oSuggResult, nDeep=0, iAddr=0, sNewWord=""):
        "returns a set of suggestions"
        # recursive function
        #logging.info((nDeep * "  ") + sNewWord + ":" + sRemain)
        aSugg = set()
        if not sRemain:
            if int.from_bytes(self.byDic[iAddr:iAddr+self.nBytesArc], byteorder='big') & self._finalNodeMask:
        #logging.info((nDeep * "  ") + sNewWord)
        if nDeep >= oSuggResult.nDistLimit:
            sCleanNewWord = cp.cleanWord(sNewWord)
            if st.distanceSift4(oSuggResult.sCleanWord[:len(sCleanNewWord)], sCleanNewWord) > oSuggResult.nDistLimit:
                return
        if int.from_bytes(self.byDic[iAddr:iAddr+self.nBytesArc], byteorder='big') & self._finalNodeMask:
                #logging.info((nDeep * "  ") + "__" + sNewWord + "__")
                aSugg.add(sNewWord)
            for sTail in self._getTails(iAddr):
            oSuggResult.addSugg(sNewWord, nDeep)
        for cChar, jAddr in self._getCharArcsWithPriority(iAddr, oSuggResult.sWord[nDeep:nDeep+1]):
                #logging.info((nDeep * "  ") + "__" + sNewWord+sTail + "__")
                aSugg.add(sNewWord+sTail)
            return aSugg
        cCurrent = sRemain[0:1]
        for cChar, jAddr in self._getSimilarArcs(cCurrent, iAddr):
            self._suggest2(oSuggResult, nDeep+1, jAddr, sNewWord+cChar)
        return

    def _getCharArcs (self, iAddr):
            aSugg.update(self._suggest(sRemain[1:], nMaxDel, nMaxHardRepl, nDeep+1, jAddr, sNewWord+cChar))
        if not bAvoidLoop: # avoid infinite loop
            if cCurrent == sRemain[1:2]:
                # same char, we remove 1 char without adding 1 to <sNewWord>
                aSugg.update(self._suggest(sRemain[1:], nMaxDel, nMaxHardRepl, nDeep+1, iAddr, sNewWord))
            else:
                # switching chars
        "generator: yield all chars and addresses from node at address <iAddr>"
                aSugg.update(self._suggest(sRemain[1:2]+sRemain[0:1]+sRemain[2:], nMaxDel, nMaxHardRepl, nDeep+1, iAddr, sNewWord, True))
                # delete char
                if nMaxDel > 0:
                    aSugg.update(self._suggest(sRemain[1:], nMaxDel-1, nMaxHardRepl, nDeep+1, iAddr, sNewWord, True))
            # Phonetic replacements
            for sRepl in cp.d1toX.get(cCurrent, ()):
                aSugg.update(self._suggest(sRepl + sRemain[1:], nMaxDel, nMaxHardRepl, nDeep+1, iAddr, sNewWord, True))
            for sRepl in cp.d2toX.get(sRemain[0:2], ()):
                aSugg.update(self._suggest(sRepl + sRemain[2:], nMaxDel, nMaxHardRepl, nDeep+1, iAddr, sNewWord, True))
            # Hard replacements
            if nDeep > 3 and nMaxHardRepl and len(sRemain) >= 2:
                for nVal, kAddr in self._getArcs1(iAddr):
                    if nVal in self.dCharVal:
                        cChar = self.dCharVal[nVal]
        for nVal, jAddr in self._getArcs(iAddr):
            if nVal < self.nChar:
                yield (self.dCharVal[nVal], jAddr)
                        if cChar not in cp.d1to1.get(cCurrent, ""):
                            aSugg.update(self._suggest(sRemain[1:], nMaxDel, nMaxHardRepl-1, nDeep+1, kAddr, sNewWord+cChar, True))
            # end of word
            if len(sRemain) == 2:
                for sRepl in cp.dFinal2.get(sRemain, ()):
                    aSugg.update(self._suggest(sRepl, nMaxDel, nMaxHardRepl, nDeep+1, iAddr, sNewWord, True))
            elif len(sRemain) == 1:
                aSugg.update(self._suggest("", nMaxDel, nMaxHardRepl, nDeep+1, iAddr, sNewWord, True)) # remove last char and go on
                for sRepl in cp.dFinal1.get(sRemain, ()):
                    aSugg.update(self._suggest(sRepl, nMaxDel, nMaxHardRepl, nDeep+1, iAddr, sNewWord, True))
        return aSugg

    def _getSimilarArcs (self, cChar, iAddr):
    def _getSimilarCharArcs (self, cChar, iAddr):
        "generator: yield similar char of <cChar> and address of the following node"
        for c in cp.d1to1.get(cChar, [cChar]):
            if c in self.dChar:
                jAddr = self._lookupArcNode(self.dChar[c], iAddr)
                if jAddr:
                    yield (c, jAddr)

    def _getCharArcsWithPriority (self, iAddr, cChar):
        if not cChar:
            yield from self._getCharArcs(iAddr)
        lTuple = list(self._getCharArcs(iAddr))
        lTuple.sort(key=lambda t: 0  if t[0] in cp.d1to1.get(cChar, cChar)  else  1)
        yield from lTuple

    def _getTails (self, iAddr, sTail="", n=2):
        "return a list of suffixes ending at a distance of <n> from <iAddr>"
        aTails = set()
        for nVal, jAddr in self._getArcs(iAddr):
            if nVal < self.nChar:
                if int.from_bytes(self.byDic[jAddr:jAddr+self.nBytesArc], byteorder='big') & self._finalNodeMask:
                    aTails.add(sTail + self.dCharVal[nVal])
                if n and not aTails:
                    aTails.update(self._getTails(jAddr, sTail+self.dCharVal[nVal], n-1))
        return aTails

    def drawPath (self, sWord, iAddr=0):
        "show the path taken by <sWord> in the graph"
        cChar = sWord[0:1]  if sWord  else " "
        c1 = sWord[0:1]  if sWord  else " "
        iPos = -1
        n = 0
        print(cChar + ": ", end="")
        for nVal, jAddr in self._getArcs(iAddr):
        print(c1 + ": ", end="")
        for c2, jAddr in self._getCharArcs(iAddr):
            if nVal in self.dCharVal:
                print(self.dCharVal[nVal], end="")
                if self.dCharVal[nVal] == sWord[0:1]:
                    iNextNodeAddr = jAddr
                    iPos = n
                n += 1
            print(c2, end="")
            if c2 == sWord[0:1]:
                iNextNodeAddr = jAddr
                iPos = n
            n += 1
        if not sWord:
            return
        if iPos >= 0:
            print("\n   "+ " " * iPos + "|")
            self.drawPath(sWord[1:], iNextNodeAddr)

    def select (self, sPattern=""):

#!python3


#### DISTANCE CALCULATIONS

def longestCommonSubstring (s1, s2):
    # http://en.wikipedia.org/wiki/Longest_common_substring_problem
    # http://en.wikibooks.org/wiki/Algorithm_implementation/Strings/Longest_common_substring
    M = [ [0]*(1+len(s2)) for i in range(1+len(s1)) ]
    longest, x_longest = 0, 0
    for x in range(1, 1+len(s1)):
        for y in range(1, 1+len(s2)):
            if s1[x-1] == s2[y-1]:
                M[x][y] = M[x-1][y-1] + 1
                if M[x][y] > longest:
                    longest = M[x][y]
                    x_longest = x
            else:
                M[x][y] = 0
    return s1[x_longest-longest : x_longest]


def distanceDamerauLevenshtein (s1, s2):
    "distance of Damerau-Levenshtein between <s1> and <s2>"
    # https://fr.wikipedia.org/wiki/Distance_de_Damerau-Levenshtein
    d = {}
    nLen1 = len(s1)
    nLen2 = len(s2)
    for i in range(-1, nLen1+1):
        d[i, -1] = i + 1
    for j in range(-1, nLen2+1):
        d[-1, j] = j + 1
    for i in range(nLen1):
        for j in range(nLen2):
            nCost = 0  if s1[i] == s2[j]  else 1
            d[i, j] = min(
                d[i-1, j]   + 1,        # Deletion
                d[i,   j-1] + 1,        # Insertion
                d[i-1, j-1] + nCost,    # Substitution
            )
            if i and j and s1[i] == s2[j-1] and s1[i-1] == s2[j]:
                d[i, j] = min(d[i, j], d[i-2, j-2] + nCost)     # Transposition
    return d[nLen1-1, nLen2-1]


def distanceSift4 (s1, s2, nMaxOffset=5):
    "implementation of general Sift4."
    # https://siderite.blogspot.com/2014/11/super-fast-and-accurate-string-distance.html
    if not s1:
        return len(s2)
    if not s2:
        return len(s1)
    nLen1, nLen2 = len(s1), len(s2)
    i1, i2 = 0, 0   # Cursors for each string
    nLargestCS = 0  # Largest common substring
    nLocalCS = 0    # Local common substring
    nTrans = 0      # Number of transpositions ('ab' vs 'ba')
    lOffset = []    # Offset pair array, for computing the transpositions
 
    while i1 < nLen1 and i2 < nLen2:
        if s1[i1] == s2[i2]:
            nLocalCS += 1
            # Check if current match is a transposition
            bTrans = False
            i = 0
            while i < len(lOffset):
                t = lOffset[i]
                if i1 <= t[0] or i2 <= t[1]:
                    bTrans = abs(i2-i1) >= abs(t[1] - t[0])
                    if bTrans:
                        nTrans += 1
                    elif not t[2]:
                        t[2] = True
                        nTrans += 1
                    break
                elif i1 > t[1] and i2 > t[0]:
                    del lOffset[i]
                else:
                    i += 1
            lOffset.append([i1, i2, bTrans])
        else:
            nLargestCS += nLocalCS
            nLocalCS = 0
            if i1 != i2:
                i1 = i2 = min(i1, i2)
            for i in range(nMaxOffset):
                if i1 + i >= nLen1 and i2 + i >= nLen2:
                    break
                elif i1 + i < nLen1 and s1[i1+i] == s2[i2]:
                    i1 += i - 1
                    i2 -= 1
                    break
                elif i2 + i < nLen2 and s1[i1] == s2[i2+i]:
                    i2 += i - 1
                    i1 -= 1
                    break
        i1 += 1
        i2 += 1
        if i1 >= nLen1 or i2 >= nLen2:
            nLargestCS += nLocalCS
            nLocalCS = 0
            i1 = i2 = min(i1, i2)
    nLargestCS += nLocalCS
    return round(max(nLen1, nLen2) - nLargestCS + nTrans)


def showDistance (s1, s2):
    print(f"Damerau-Levenshtein: {s1} / {s2} = {distanceDamerauLevenshtein(s1, s2)}")
    print(f"Sift4: {s1} / {s2} = {distanceSift4(s1, s2)}")




#### STEMMING OPERATIONS

## No stemming

def noStemming (sFlex, sStem):
    return sStem

def rebuildWord (sFlex, cmd1, cmd2):
    if cmd1 == "_":

        return "0"
    jSfx = 0
    for i in range(min(len(sFlex), len(sStem))):
        if sFlex[i] != sStem[i]:
            break
        jSfx += 1
    return chr(len(sFlex)-jSfx+48) + sStem[jSfx:]  


def changeWordWithSuffixCode (sWord, sSfxCode):
    if sSfxCode == "0":
        return sWord
    return sWord[:-(ord(sSfxCode[0])-48)] + sSfxCode[1:]  if sSfxCode[0] != '0'  else sWord + sSfxCode[1:]


# Prefix and suffix

def defineAffixCode (sFlex, sStem):
    """ Returns a string defining how to get stem from flexion. Examples:
            "0" if stem = flexion
            "stem" if no common substring
            "n(pfx)/m(sfx)"
        with n and m: chars with numeric meaning, "0" = 0, "1" = 1, ... ":" = 10, etc. (See ASCII table.) Says how many letters to strip from flexion.
            pfx [optional]: string to add before the flexion 

        n = sFlex.find(sSubs)
        m = len(sFlex) - (len(sSubs)+n)
        sAff = "{}/".format(chr(n+48))  if not sPfx  else "{}{}/".format(chr(n+48), sPfx)
        sAff += chr(m+48)  if not sSfx  else "{}{}".format(chr(m+48), sSfx)
        return sAff
    return sStem

def longestCommonSubstring (s1, s2):
    # http://en.wikipedia.org/wiki/Longest_common_substring_problem
    # http://en.wikibooks.org/wiki/Algorithm_implementation/Strings/Longest_common_substring
    M = [ [0]*(1+len(s2)) for i in range(1+len(s1)) ]
    longest, x_longest = 0, 0
    for x in range(1, 1+len(s1)):
        for y in range(1, 1+len(s2)):
            if s1[x-1] == s2[y-1]:
                M[x][y] = M[x-1][y-1] + 1
                if M[x][y] > longest:
                    longest = M[x][y]
                    x_longest = x
            else:
                M[x][y] = 0
    return s1[x_longest-longest : x_longest]

def changeWordWithAffixCode (sWord, sAffCode):
    if sAffCode == "0":
        return sWord
    if '/' not in sAffCode:
        return "# error #"
    sPfxCode, sSfxCode = sAffCode.split('/')
    sWord = sPfxCode[1:] + sWord[(ord(sPfxCode[0])-48):] 
    return sWord[:-(ord(sSfxCode[0])-48)] + sSfxCode[1:]  if sSfxCode[0] != '0'  else sWord + sSfxCode[1:]