support missing dummy row in asc files

[dkrako]

Description of the problem

There are configurations of EyeLink eye trackers that lead to unparsed eye tracking samples.

The following regex:

EYE_TRACKING_SAMPLE = re.compile(
    r'(?P<time>(\d+[.]?\d*))\s+'
    r'(?P<x_pix>[-]?\d*[.]\d*)\s+'
    r'(?P<y_pix>[-]?\d*[.]\d*)\s+'
    r'(?P<pupil>\d*[.]\d*)\s+'
    r'(?P<dummy>\d*[.]\d*)\s+'
    r'(?P<dots>[A-Za-z.]{3,5})?\s*',
)

match: 2498958 77.1 96.4 454.0 0.0 ...

no match: 677671 1488.6 309.1 1085.0 ...

The second

Description of a solution

An alternative regex definition that would match both lines:

EYE_TRACKING_SAMPLE = re.compile(
    r'(?P<time>(\d+[.]?\d*))\s+'
    r'(?P<x_pix>[-]?\d*[.]\d*)\s+'
    r'(?P<y_pix>[-]?\d*[.]\d*)\s+'
    r'(?P<pupil>\d*[.]\d*)\s+'
    r'((?P<dummy>\d*[.]\d*)\s+)?'
    r'(?P<dots>[A-Za-z.]{3,5})?\s*',
)

The difference is in the dummy line. This way the dummy row is completely optional by using ?.

Context

The differences between the two example messages seem to result from MODE RECORD:

• !MODE RECORD CR 1000 0 0 R -- has dummy 0 on 5th column
• !MODE RECORD CR 500 2 1 L -- does not have dummy 0

Disclaimer

I copied substantial parts of descirption, proposal and data from @senisioi

[dkrako]

@saeub can you post the info on the row specification you showed in the meeting today for reference? it was in one of the manuals right?

[saeub]

From the User Manual of the EyeLink Portable Duo (Version 1.0.9), section 4.9.2 (p. 92):

SAMPLE LINE FORMATS

• Monocular:
  <time> <xp> <yp> <ps>
• Monocular, with velocity
  <time> <xp> <yp> <ps> <xv> <yv>
• Monocular, with resolution
  <time> <xp> <yp> <ps> <xr> <yr>
• Monocular, with velocity and resolution
  <time> <xp> <yp> <ps> <xv> <yv> <xr> <yr>
• Binocular
  <time> <xpl> <ypl> <psl> <xpr> <ypr> <psr>
• Binocular, with velocity
  <time> <xpl> <ypl> <psl> <xpr> <ypr> <psr> <xvl> <yvl> <xvr> <yvr>
• Binocular, with resolution
  <time> <xpl> <ypl> <psl> <xpr> <ypr> <psr> <xr> <yr>
• Binocular, with velocity and resolution
  <time> <xpl> <ypl> <psl> <xpr> <ypr> <psr> <xvl> <yvl> <xvr> <yvr> <xr> <yr>

The manual doesn't mention the -input flag, so that might add some more possible formats.