Module:Math

    From Nonbinary Wiki
    Revision as of 20:04, 21 February 2013 by m>Dragons flight

    Documentation for this module may be created at Module:Math/doc

    local z = {}
    
    -- Generate random number
    function z.random( frame )
        first = tonumber(frame.args[1]) -- if it doesn't exist it's NaN, if not a number it's nil
        second = tonumber(frame.args[2])
    
        if first then -- if NaN or nil, will skip down to final return
            if first <= second then -- could match if both nil, but already checked that first is a number in last line
                return math.random(first, second)
            end
            return math.random(first)
        end   
        return math.random()
    end
    
    -- Determine order of magnitude
    function z.order(frame)
        return z._order(tonumber(frame.args[1] or frame.args.x or 0))
    end
    function z._order(x)
        if x == 0 then return 0 end
        return math.floor(math.log10(math.abs(x)))
    end
    
    -- Determines precision of a number using the string representation
    function z.precision( frame )
        return z._precision( frame.args[1] or frame.args.x or '0' )
    end
    function z._precision( x )
        x = string.upper( x )
    
        -- Remove leading / trailing whitespace
        x = x:match "^%s*(.-)%s*$";
    
        local decimal = string.find( x, '.', 1, true )
        local exponent_pos = string.find( x, 'E', 1, true )
        local result = 0;
        
        if exponent_pos ~= nil then
            local exponent = string.sub( x, exponent_pos + 1 )
            x = string.sub( x, 1, exponent_pos - 1 )
            result = result - tonumber( exponent )
        end    
        
        if decimal ~= nil then
            result = result + string.len( x ) - decimal
            return result
        end
            
        local pos = string.len( x );
        while x:byte(pos) == string.byte('0') do
            pos = pos - 1
            result = result - 1
            if pos <= 0 then
                return 0
            end
        end
        
        return result
    end
    
    -- Finds maximum argument
    function z.max( frame )
        if frame.args[1] == nil then
            return ''
        end
        local max_value = tonumber( frame.args[1] )
        
        local i = 2;
        while frame.args[i] ~= nil do
            local val = tonumber( frame.args[i] );
            if val ~= nil then
                if val > max_value then
                    max_value = val;
                end
            end        
            i = i + 1;
        end
      
        return max_value
    end
    
    -- Finds minimum argument
    function z.min( frame )
        if frame.args[1] == nil then
            return ''
        end
        local min_value = tonumber( frame.args[1] )
        
        local i = 2;
        while frame.args[i] ~= nil do
            local val = tonumber( frame.args[i] );
            if val ~= nil then
                if val < min_value then
                    min_value = val;
                end
            end        
            i = i + 1;
        end
      
        return min_value
    end
    
    -- Rounds a number to the specified precision and formats according to rules 
    -- originally used for {{template:Rnd}}
    function z.round( frame )
        -- For access to Mediawiki built-in formatter.
        local lang = mw.getContentLanguage();
        
        local value = tonumber( frame.args[1] or 0 );
        local precision = tonumber( frame.args[2] or 0 );
        local current_precision = z._precision( value );
        
        -- If rounding off, truncate extra digits
        if precision < current_precision then
            local rescale = math.pow( 10, precision );
            value = math.floor( value * rescale + 0.5 ) / rescale;
        end    
        
        local formatted_num = lang:formatNum( math.abs(value) );
        local sign;
        
        -- Use proper unary minus sign rather than ASCII default
        if value < 0 then
            sign = '−';
        else
            sign = '';
        end    
        
        local order;
        
        -- Handle cases requiring scientific notation
        order = z._order( value );
        if string.find( formatted_num, 'E', 1, true ) ~= nil or math.abs(order) >= 9 then
            value = value * math.pow( 10, -order );
            current_precision = current_precision + order;
            precision = precision + order;
            formatted_num = lang:formatNum( value );
        else
            order = 0;        
        end
        formatted_num = sign .. formatted_num;
        
        -- Pad with zeros, if needed
        if current_precision < precision then
            if current_precision <= 0 then
                if precision > 0 then
                    local zero_sep = lang:formatNum( 1.1 );
                    formatted_num = formatted_num .. zero_sep:sub(2,2);
                    formatted_num = formatted_num .. string.rep( '0', precision );
                end            
            else       
                formatted_num = formatted_num .. string.rep( '0', precision - current_precision );
            end
        end
    
        -- Add exponential notation, if necessary.
        if order ~= 0 then
            -- Use proper unary minus sign rather than ASCII default
            if order < 0 then
                order = '−' .. lang:formatNum( math.abs(order) );
            else
                order = lang:formatNum( order );
            end    
            
            formatted_num = formatted_num .. '<span style="margin:0 .15em 0 .25em">×</span>10<sup>' .. order .. '</sup>'
        end
        
        return formatted_num;
    end
    
    return z