function [outFis,outTxtRuleList,errorStr]=parsrule(fis,inTxtRuleList,ruleFormat,lang)
%PARSRULE Parse fuzzy rules.
%   This function parses the text that defines the rules (txtRuleList) for a 
%   fuzzy system (fis) and returns a FIS structure with the appropriate rule 
%   list in place. If the original input FIS structure, fis, has any rules 
%   initially, they are replaced in the new matrix fis2. Three different rule 
%   formats (indicated by ruleFormat) are supported: *verbose*, *symbolic*, and 
%   *indexed*. The default format is *verbose*. When the optional language 
%   argument (lang) is used, the rules are parsed in verbose mode, assuming the 
%   key words are in the language, lang. This language must be either 
%   'english', 'francais', or 'deutsch'. The key language words in English are: 
%   IF, THEN, IS, AND, OR, and NOT. 
%   
%   outFIS = PARSRULE(inFIS,inRuleList) parses the rules in the string
%   matrix inRuleList and returns the updated FIS matrix outFIS. 
%
%   outFIS = PARSRULE(inFIS,inRuleList,ruleFormat) parses the rules using
%   the given ruleFormat.
%
%   outFIS = PARSRULE(inFIS,inRuleList,ruleFormat,lang) parses the 
%   rules in verbose mode assuming the key words are in the language, lang.
%
%   For example:
%
%           a=newfis('tipper');
%           a=addvar(a,'input','service',[0 10]);
%           a=addmf(a,'input',1,'poor','gaussmf',[1.5 0]);
%           a=addvar(a,'input','food',[0 10]);
%           a=addmf(a,'input',2,'rancid','trapmf',[-2 0 1 3]);
%           a=addvar(a,'output','tip',[0 30]);
%           a=addmf(a,'output',1,'cheap','trimf',[0 5 10]);
%           rule1='if service is poor or food is rancid then tip is cheap';
%           a=parsrule(a,rule1);
%           showrule(a)
%   
%   See also ADDRULE, RULEEDIT, SHOWRULE.

%   [outFIS,outRuleList,errorStr] = PARSRULE(...) returns the text version
%   of the newly-parsed rules. If there have been errors in the parsing,
%   the error message is returned in errorStr, and the # character is placed
%   at the beginning of the offending line in outRuleList.
%
%   Ned Gulley, 4-27-94
%   Copyright 1994-2002 The MathWorks, Inc. 
%   $Revision: 1.29 $  $Date: 2002/04/19 02:49:30 $

if nargin<3,
    ruleFormat='verbose';
end

if nargin<4,
    lang='english';
end
outTxtRuleList=[];
errorStr=[];
if ~strcmp(ruleFormat,'indexed'),
    if strcmp(lang,'english'),
        ifStr=' if ';
        andStr='and';
        orStr='or';
        thenStr='then';
        equalStr=' is ';
        isStr=' is ';
        notStr='not';
    elseif strcmp(lang,'francais'),
        ifStr=' si ';
        andStr='et';
        orStr='ou';
        thenStr='alors';
        equalStr=' est ';
        isStr=' est ';
        notStr='n''est_pas';
    elseif strcmp(lang,'deutsch'),
        ifStr=' wenn ';
        andStr='und';
        orStr='oder';
        thenStr='dann';
        equalStr=' ist ';
        isStr=' ist ';
        notStr='nicht';
    elseif strcmp(lang,'svenska'),
        ifStr=' om ';
        andStr='och';
        orStr='eller';
        thenStr='innebar_att';
        equalStr=' aer ';
        isStr=' aer ';
        notStr='inte';
    end
end

% Determine all the necessary constants
numInputs=length(fis.input);
numOutputs=length(fis.output);

for i=1:length(fis.input)
 numInputMFs(i)=length(fis.input(i).mf);
end
numOutputMFs=[];
for i=1:length(fis.output)
 numOutputMFs(i)=length(fis.output(i).mf);
end

if isempty(inTxtRuleList),
    outFis=setfis(fis,'ruleList',[]);
    return
end

% Remove any rows that are nothing but blanks
index=find(inTxtRuleList==0);
inTxtRuleList(index)=32*ones(size(index));
inTxtRuleList(all(inTxtRuleList'==32),:)=[];
if isempty(inTxtRuleList),
    outFis=setfis(fis,'ruleList',[]);
    return
end

% Replace all punctuation (and zeros) with spaces (ASCII 32)
inTxtRuleList2=inTxtRuleList;
index=[
    find(inTxtRuleList2==',')
    find(inTxtRuleList2=='#')
    find(inTxtRuleList2==':')
    find(inTxtRuleList2=='(')
    find(inTxtRuleList2==')')];
inTxtRuleList2(index)=32*ones(size(index));
inTxtRuleList2(all(inTxtRuleList2'==32),:)=[];

if isempty(inTxtRuleList2),
    outFis=setfis(fis,'ruleList',[]);
    return
end

inTxtRuleList2=setstr(inTxtRuleList2);
numRules=size(inTxtRuleList2,1);

if strcmp(ruleFormat,'symbolic'),
    symbFlag=1;
else
    symbFlag=0;
end

if strcmp(ruleFormat,'indexed'),
    ruleList=zeros(numRules,numInputs+numOutputs+2);
    errRuleIndex=[];
    goodRuleIndex=[];
    errorFlag=0;
    for ruleIndex=1:numRules,
        str=['[' inTxtRuleList2(ruleIndex,:) ']'];
        rule=eval(str,'[]');
        if isempty(rule),
            errorStr=['Rule did not evaluate properly.'];
            if nargout<3,
                error(errorStr);
            else
                errorFlag=1;
            end
        elseif length(rule)<(numInputs+numOutputs)+2,
            errorStr=['Not enough columns for this rule. The rule is not complete.'];
            if nargout<3,
                error(errorStr);
            else
                errorFlag=1;
            end
        elseif length(rule)>(numInputs+numOutputs)+2,
            errorStr=['Too many columns for this rule.'];
            if nargout<3,
                error(errorStr);
            else
                errorFlag=1;
            end
        elseif any(abs(rule(1:numInputs))>numInputMFs),
            errorStr=['Input MF index is too high'];
            if nargout<3,
                error(errorStr);
            else
                errorFlag=1;
            end
        elseif any(abs(rule((1:numOutputs)+numInputs))>numOutputMFs),
            errorStr=['Output MF index is too high'];
            if nargout<3,
                error(errorStr);
            else
                errorFlag=1;
            end
        elseif rule(numOutputs+numInputs+1)>1 | rule(numOutputs+numInputs+1)<0,
            errorStr=['Rule weight must be between 0 and 1'];
            if nargout<3,
                error(errorStr);
            else
                errorFlag=1;
            end
        elseif rule(numOutputs+numInputs+2)~=1 & rule(numOutputs+numInputs+2)~=2,
            errorStr=['Fuzzy operator must be either 1 (AND) or 2 (OR)'];
            if nargout<3,
                error(errorStr);
            else
                errorFlag=1;
            end
        else
            ruleList(ruleIndex,:)=rule;
        end

        if errorFlag,
            errRuleIndex=[errRuleIndex ruleIndex];
        else
            goodRuleIndex=[goodRuleIndex ruleIndex];
        end
        errorFlag=0;
    end

else
    % symbolic format is first converted to verbose and then
    % everything is parsed as verbose text

    inLabels=lower(getfis(fis,'inLabels'));
    inMFLabels=lower(getfis(fis,'inMFLabels'));
    outLabels=lower(getfis(fis,'outLabels'));
    outMFLabels=lower(getfis(fis,'outMFLabels'));

    % String pre-processing
    % Use "lower" to make it case insensitive
    inTxtRuleList2=lower(inTxtRuleList2);

    antCode=zeros(numRules,numInputs);
    consCode=zeros(numRules,numOutputs);
    andOrCode=ones(numRules,1);
    wtCode=ones(numRules,1);

    errorFlag=0;
    errRuleIndex=[];
    goodRuleIndex=[];

    for ruleIndex=1:numRules,
        txtRule=inTxtRuleList2(ruleIndex,:);