Class: Parser

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/mulparse/parser.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(src, lang_config) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/mulparse/parser.rb', line 24

def initialize( src, lang_config )

    # Initialize a parser and set lang_config and other parsing configurations

    @src = src # src must be loaded from a text stream not a binary one

    if lang_config.class == String then
        
        # Open predefined lang-config
        
        @lang_config = YAML.load( IO.read(
            "#{File.absolute_path( File.expand_path( File.join( File.dirname( __FILE__ ), '..' ) ) )}" \
            "/mulparse/lang-configs/#{lang_config}.yaml" 
        ) )

    else
        # Else use user provided lang-config
        @lang_config = lang_config
    end

    @position = 0

    # Store the current Component
    @current = Component.new( finish: true )

end

Instance Attribute Details

#src ⇒ Object (readonly)

Returns the value of attribute src.



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# File 'lib/mulparse/parser.rb', line 22

def src
  @src
end

Instance Method Details

#each(&block) ⇒ Object 



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# File 'lib/mulparse/parser.rb', line 51

def each( &block )

    # Implements each method defined in Enumerable.
    # This method passes the next component parsed
    # in the srouce. The component is in the form
    # of a Component.

    loop do
    
        # Either finish the currentCN or open a new one on each iteration

        # Get the next start delimiter and its corresponding lcEntry

        next_start, start_entry = get_next_start()

        # Keep track of the existance of the finish attribute
        has_finish = @current.finish && @current.finish != true # A true value indicates the root Component

        if has_finish then

            # If finsih regex provided prepare closing regex

            closing_regex = @current.finish

            if closing_regex.is_a?( String ) then
                
                # Format in mirror to the closing_regex if mirror is provided

                if @current.hash then

                    # Process hash argument if provided

                    closing_regex = Regexp.new( closing_regex % Hash.new { |_, key|
                        Regexp.escape( @current.hash[ @current.start_match[ key ] ] || @current.start_match[ key ] )
                    } )

                else

                    # Else process normally

                    closing_regex = Regexp.new( closing_regex % Hash.new { |_, key|
                        Regexp.escape( @current.start_match[ key ] )
                    } )

                end

            end

            # Match for next closing delimiter
            next_finish = closing_regex.match( @src, @position )
            
            raise UnmatchedException.new(
                @current.name,
                @src[ 0..@current.start_match.end( 0 ) ].count( "\n" ) + 1
            ) unless next_finish

            # Ensure "escape" capture is valid

            until next_finish[ :escape ].length.even?

                # Match until length of "escape" capture is even
                next_finish = closing_regex.match( @src, next_finish.end( 0 ) )
            
            end if closing_regex.names.include?( "escape" )

        end

        if !next_start then
            
            # If done parsing yield last Component

            @current.finish_match = next_finish
            yield @current

            break

        end

        break if !next_start # Break if pasrsing is complete

        if @current&.parent && ( has_finish &&
            ( @current.unestable || next_finish.begin( 0 ) < next_start.begin( 0 ) ) ) then
        
            # If current Component should be finished then finish it

            begin
                @position = next_finish.end( 0 ) # Update position
            rescue NoMethodError
                
                # Raise UnmatchedException if next_finish is nil

                raise UnmatchedException.new(
                    @current.name,
                    @src[ 0..@current.start_match.end( 0 ) ].count( "\n" ) + 1
                )
                
            end

            # Update parsing data
            @current.finish_match = next_finish

            # Yield finished Component
            yield @current

            # Set current Component to the previous's parent
            @current = @current.parent

        else

            # Else new Component is found set it as current

            @current = Component.new( next_start, @current, start_entry )
            @position = next_start.end( 0 ) # Update position

            # Yield if Component uses syntactic sugar unestability
            
            unless @current.finish && @current.finish != true  then
                yield @current
                @current = @current.parent
            end

        end

    end

end

#line ⇒ Object

External/Internal Utility Methods



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# File 'lib/mulparse/parser.rb', line 180

def line

    # Return number of lines already parsed
    return @src[ 0..@position ].count( "\n" )

end