christopherh@1: %
christopherh@1: %PARSECHORD parse chord symbol to its constituent string elements
christopherh@1: % 
christopherh@1: % [rootnote, shorthand, intervals, bass, success, errormessage]
christopherh@1: %                                   = parsechord(chord, {verbose})
christopherh@1: % 	
christopherh@1: % Parses the chord symbol string "chord" into its separate string elements. 
christopherh@1: % 
christopherh@1: % NOTE: This function does not check validity of the chord elements, it
christopherh@1: % merely separates them according to the chord syntax. 
christopherh@1: % To obtain chord elements with included validity check use GETCHORDINFO.
christopherh@1: %
christopherh@1: % Success = 1 if symbols parsed correctly, 0 otherwise.
christopherh@1: %
christopherh@1: % If optional argument 'verbose' is 1, function prints any errormessage to 
christopherh@1: % the screen.
christopherh@1: % 	
christopherh@1: % returns:  rootnote        (note string)
christopherh@1: %           shorthand       (shorthand string)
christopherh@1: %           intervals       (interval-list string)
christopherh@1: %           bass            (interval string)
christopherh@1: %           success         (boolean)
christopherh@1: %           errormessage    (string)
christopherh@1: %
christopherh@1: % See also: getchordinfo                     
christopherh@1: %
christopherh@1: % Author: Christopher Harte, March 2009
christopherh@1: % 
christopherh@1: % Copyright: Centre for Digital Music, Queen Mary University of London 2005 
christopherh@1: %
christopherh@1: % This file is part of the C4DM Chord Toolkit V2.0  
christopherh@1: %
christopherh@1: % The C4DM Chord Toolkit is free software; you can redistribute it and/or 
christopherh@1: % modify it under the terms of the GNU General Public License as published 
christopherh@1: % by the Free Software Foundation; either version 2 of the License, or
christopherh@1: % (at your option) any later version.
christopherh@1: %
christopherh@1: % The C4DM Chord Toolkit is distributed in the hope that it will be useful,
christopherh@1: % but WITHOUT ANY WARRANTY; without even the implied warranty of
christopherh@1: % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
christopherh@1: % GNU General Public License for more details.
christopherh@1: %
christopherh@1: % You should have received a copy of the GNU General Public License
christopherh@1: % along with the C4DM Toolkit; if not, write to the Free Software
christopherh@1: % Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
christopherh@1: 
christopherh@1: %		
christopherh@1: function  [rootnote, shorthand, intervals, bass, success, errormessage] = parsechord(chord, verbose)
christopherh@1: 	
christopherh@1: % set verbose default to 0
christopherh@1: if nargin <2
christopherh@1:     verbose = 0;
christopherh@1: end
christopherh@1: 
christopherh@1: ilength = length(chord);
christopherh@1: 
christopherh@1: % initialise variables
christopherh@1: errormessage = '';
christopherh@1: rootnote = '';
christopherh@1: shorthand = '';
christopherh@1: intervals = '';
christopherh@1: bass = '';
christopherh@1: 
christopherh@1: success = 1;
christopherh@1: index = 1;
christopherh@1: 
christopherh@1: 
christopherh@1: % check for 'no chord' symbol
christopherh@1: if chord(index) == 'N'
christopherh@1:     rootnote = chord(index);
christopherh@1:     index = index +1;
christopherh@1:     % check to see there are no further characters
christopherh@1:     if(index<=ilength)
christopherh@1:         errormessage = sprintf(['Error in parsechord: \nExtra characters after "no chord" symbol "' chord '"\n']); 
christopherh@1:         success = 0;
christopherh@1:     end
christopherh@1: else
christopherh@1: % parse thechord symbol
christopherh@1: 
christopherh@1:     % the first part of the symbol before a switch character should be the root note
christopherh@1:     while ((index <=ilength ))
christopherh@1:     
christopherh@1:         if (chord(index) ==  ':') || (chord(index) ==  '/') || ...
christopherh@1:            (chord(index) ==  '(') || (chord(index) ==  ')')
christopherh@1:             
christopherh@1:             break
christopherh@1:         end
christopherh@1: 
christopherh@1:         rootnote(index) = chord(index);
christopherh@1:         index = index+1;
christopherh@1:     
christopherh@1:         if(index > ilength) || (chord(index) == '/')
christopherh@1:             % if chord is a rootnote on its own or with just a bass note 
christopherh@1:             % then it is a major chord therefore set shorthand to 'maj'
christopherh@1:             shorthand = 'maj';
christopherh@1:         end
christopherh@1:     end
christopherh@1:     
christopherh@1:     % initialise booleans to record which switch characters we have found
christopherh@1:     colon = 0;
christopherh@1:     openbracket = 0;
christopherh@1:     closebracket = 0;
christopherh@1:     slash = 0;
christopherh@1:     
christopherh@1:     % parse the rest of the chord symbol
christopherh@1:     while(index <= ilength)
christopherh@1:         
christopherh@1:         % reset temporary index 
christopherh@1:         tempindex = 1;
christopherh@1:         
christopherh@1:        switch(chord(index))
christopherh@1:        
christopherh@1:            case ':'  
christopherh@1:                         
christopherh@1:                % if we find a colon after any switch characters have 
christopherh@1:                % already occured then the symbol is incorrect 
christopherh@1:                if (colon || openbracket || closebracket || slash)
christopherh@1:                     errormessage = sprintf(['Error in parsechord: \nIncorrect character sequence in chord "' chord '"\n']); 
christopherh@1:                     success = 0;
christopherh@1:                     index = ilength+1;
christopherh@1:                else
christopherh@1:                 
christopherh@1:                    % found the first instance of a colon character
christopherh@1:                    colon = 1;
christopherh@1:                    
christopherh@1:                    index = index +1;
christopherh@1:                    
christopherh@1:                    if(index > ilength)
christopherh@1:                         errormessage = sprintf(['Error in parsechord: \nFound ":" at end of chord string "' chord '"\n']); 
christopherh@1:                         success = 0; 
christopherh@1:                    end
christopherh@1:                    % colon should be followed by a shorthand string or
christopherh@1:                    % an interval list contained in brackets
christopherh@1:                    while (index <= ilength)
christopherh@1:                        
christopherh@1:                        if (chord(index) ==  ':') || (chord(index) ==  '/') || ...
christopherh@1:                           (chord(index) ==  '(') || (chord(index) ==  ')')
christopherh@1: 
christopherh@1:                            break
christopherh@1:                        end
christopherh@1: 
christopherh@1:                        % copy character into shorthand
christopherh@1:                        shorthand(tempindex) = chord(index);
christopherh@1:                        index = index +1;
christopherh@1:                        tempindex = tempindex +1;
christopherh@1: 
christopherh@1:                    end
christopherh@1:                
christopherh@1:                end
christopherh@1:                
christopherh@1:            case '('
christopherh@1:                
christopherh@1:                % if we have had a colon but no other switch charaters then
christopherh@1:                % an open bracket signifies the start of the interval list
christopherh@1:                if (colon && ~slash && ~closebracket && ~openbracket) 
christopherh@1:                    
christopherh@1:                    openbracket = 1;
christopherh@1:                    
christopherh@1:                    index = index +1;
christopherh@1:                    
christopherh@1:                    while (index <= ilength)
christopherh@1: 
christopherh@1:                        if (chord(index) ==  ':') || (chord(index) ==  '/') || ...
christopherh@1:                           (chord(index) ==  '(') || (chord(index) ==  ')')
christopherh@1: 
christopherh@1:                            break
christopherh@1:                        end
christopherh@1:                        
christopherh@1:                        % copy character into intervals
christopherh@1:                        intervals(tempindex) = chord(index);
christopherh@1:                        index = index +1;
christopherh@1:                        tempindex = tempindex +1;
christopherh@1: 
christopherh@1:                    end
christopherh@1:                    
christopherh@1:                    if(index > ilength)
christopherh@1:                         errormessage = sprintf(['Error in parsechord: \nInterval list brackets not closed in chord "' chord '"\n']); 
christopherh@1:                         success = 0; 
christopherh@1:                    end
christopherh@1:                    
christopherh@1:                else
christopherh@1:                    errormessage = sprintf(['Error in parsechord: \nIncorrect character sequence in chord "' chord '"\n']); 
christopherh@1:                    success = 0;
christopherh@1:                    index = ilength +1;
christopherh@1:                end
christopherh@1:                
christopherh@1:            case ')'
christopherh@1:                
christopherh@1:                
christopherh@1:                % if we find a closing bracket then we should either be at
christopherh@1:                % the end of the symbol or there should be a slash to follow
christopherh@1:                if (colon && openbracket && ~slash && ~closebracket) 
christopherh@1:                    
christopherh@1:                    closebracket = 1;
christopherh@1:                    index = index +1;
christopherh@1:                    
christopherh@1:                else
christopherh@1:                    errormessage = sprintf(['Error in parsechord: \nIncorrect character sequence in chord "' chord '"\n']); 
christopherh@1:                    success = 0;
christopherh@1:                    index = ilength +1;
christopherh@1:                end
christopherh@1:                
christopherh@1:                % check to see that the brackets contained something
christopherh@1:                if isempty(intervals)
christopherh@1:                    errormessage = sprintf(['Error in parsechord: \nBrackets contain no intervals in chord "' chord '"\n']); 
christopherh@1:                    success = 0;
christopherh@1:                    index = ilength +1;
christopherh@1:                end
christopherh@1:                
christopherh@1:                
christopherh@1:            case '/'
christopherh@1:                % forward slash should be followed by an interval string
christopherh@1:               
christopherh@1:                    slash = 1;
christopherh@1: 
christopherh@1:                    % move on to next character to process the expected bass interval
christopherh@1:                    index = index +1;
christopherh@1:                                      
christopherh@1:                    % check that we haven't overun the end of the symbol string
christopherh@1:                    if(index > ilength)
christopherh@1:                         errormessage = sprintf(['Error in parsechord: \nNo bass interval "/" at end of chord "' chord '"\n']); 
christopherh@1:                         success = 0; 
christopherh@1:                    end
christopherh@1:                    
christopherh@1:                    % check that if we have had an open bracket that it also
christopherh@1:                    % had a closed bracket
christopherh@1:                    if(xor(openbracket,closebracket))
christopherh@1:                         errormessage = sprintf(['Error in parsechord: \nFound "/" before closing bracket in chord "' chord '"\n']); 
christopherh@1:                         success = 0; 
christopherh@1:                         index = ilength +1;
christopherh@1:                    end
christopherh@1: 
christopherh@1:                    % check that the previous character was not a ':'
christopherh@1:                    if(chord(index-2) == ':')
christopherh@1:                         errormessage = sprintf(['Error in parsechord: \nFound "/" directly after ":" in chord "' chord '"\n']); 
christopherh@1:                         success = 0; 
christopherh@1:                         index = ilength +1;
christopherh@1:                    end
christopherh@1: 
christopherh@1:                    
christopherh@1:                    while( index <= ilength )
christopherh@1:                        
christopherh@1:                        % if we find a switch character after a slash then
christopherh@1:                        % the symbol is incorrect
christopherh@1:                        if (chord(index) ==  ':') || (chord(index) ==  '/') || ...
christopherh@1:                           (chord(index) ==  '(') || (chord(index) ==  ')')
christopherh@1:          
christopherh@1:                            errormessage = sprintf(['Error in parsechord: \nIncorrect character sequence in chord "' chord '"\n']); 
christopherh@1:                            success = 0;
christopherh@1:                            index = ilength +1;
christopherh@1:                        
christopherh@1:                        else
christopherh@1: 
christopherh@1:                            % copy remaining characters into bass
christopherh@1:                            bass(tempindex) = chord(index);
christopherh@1:                            index = index +1;
christopherh@1:                            tempindex = tempindex +1;
christopherh@1:                        end
christopherh@1:                    end
christopherh@1:                             
christopherh@1:            otherwise
christopherh@1:                 errormessage = sprintf(['Error in parsechord: \nUnrecognised chord "' chord '"\n']); 
christopherh@1:                 success = 0;
christopherh@1:                 index = ilength + 1;
christopherh@1:        end
christopherh@1:             
christopherh@1:     end
christopherh@1: end            
christopherh@1:             
christopherh@1: if (verbose == 1) && (success == 0)
christopherh@1:     fprintf(1,errormessage);
christopherh@1: end
christopherh@1:         
christopherh@1: