module Track: Biocaml_track
Track lines define display attributes. They can be thought of as
    lists of attribute-value pairs. For forward compatibility, this module
    allows arbitrary attributes to be set. However, the following lists
    known attributes and specifies restrictions on their values:
- name- string enclosed in double quotes if there are spaces;
      recommended to use only alphanumeric characters and length less
      than 15 characters but this is not enforced
- description- string enclosed in double quotes if there are
      spaces; recommended to use only alphanumeric characters and
      length less than 60 characters but this is not enforced
- visibility- "hide", "dense", "full", "pack", or "squish"; if- type=wiggle_0then "hide", "dense", or "full"; can also use
      integer value where 0 = "hide", 1 = "dense", 2 = "full", 3 =
      "pack", 4 = "squish"
- color- "R,G,B" where each of R, G, and B are integers between
      0 and 255
- altColor- "R,G,B" where each of R, G, and B are integers
      between 0 and 255
- itemRgb- "On" is the only allowed value
- useScore- 0 or 1
- group- string
- priority- integer
- autoScale- "on" or "off"
- gridDefault- "on" or "off"
- maxHeightPixels- "max:default:min" where each of max,
      default, and min are integers
- graphType- "bar" or "points"
- viewLimits- "lower:upper" where each of lower and upper are
      integers
- yLineMark- floating point value
- yLineOnOff- "on" or "off"
- windowingFunction- "maximum", "mean", or "minimum"
- smoothingWindow- "off" or an integer between 2 and 16
- db- should be a valid UCSC assembly ID, but currently any
      string is accepted
- offset- integer
- url- string
- htmlUrl- string
- type- "wiggle_0" is the only value currently supported,
      leaving this attribute unset handles other track types
type [ `browser of
           [ `hide of [ `all ]
           | `position of string * int * int
           | `unknown of string ]
       | `comment of string
       | `track of (string * string) list ] 
The type of the parser "track" lines.
type 'a content = [ `content of 'a ] 
The "content" lines of the files.
type [ `incomplete_input of Biocaml_pos.t * string list * string option
       | `wrong_browser_position of Biocaml_pos.t * string
       | `wrong_key_value_format of (string * string) list * string * string ] 
The possible parsing errors.
module Transform: sig .. end
Low-level transforms.