#65 lt-proc claims empty left side even if not

[Kevin Brubeck Unhammer]

$ svn co -r 54005 https://svn.code.sf.net/p/apertium/svn/incubator/apertium-sco
$ cd apertium-sco
$ lt-comp rl apertium-sco.sco.dix sco.autogen.bin
main@standard 5225 10282
$ echo '^will<vaux><inf>$' |lt-proc -g sco.autogen.bin     
Error: Invalid dictionary (hint: the left side of an entry is empty)

This happens because there's a pardef

<pardef n="na__S">
  <e>
    <p>
      <l></l>
      <r></r>
    </p>
  </e>
  <e r="LR">
    <p>
      <l>na</l>
      <r><j/>na<s n="adv"/></r>
    </p>
  </e>
  <e r="LR">
    <p>
      <l>nae</l>
      <r><j/>na<s n="adv"/></r>
    </p>
  </e>
  <e r="LR">
    <p>
      <l>naw</l>
      <r><j/>na<s n="adv"/></r>
    </p>
  </e>
</pardef>

and since all the adv's are marked LR, the generation-specific pardef becomes

<pardef n="na__S">
  <e>
    <p>
      <l></l>
      <r></r>
    </p>
  </e>
</pardef>

– for some reason this is treated as an initially-empty left-side when it should jut be a non-transition.

Perhaps the fix should be in lt-comp

[Kevin Brubeck Unhammer]

Here's a minimal dix showing the problem:

f.dix:

<?xml version="1.0" encoding="UTF-8"?>
<dictionary>

  <sdefs>
    <sdef n="adj"/>
  </sdefs>

  <pardefs>
    <pardef n="eps">
      <e><p><l></l><r></r></p></e>
    </pardef>
  </pardefs>

  <section id="main" type="standard">
    <e> <p><l>x<s n="adj"/></l> <r>x<s n="adj"/></r></p><par n="eps"/></e>
  </section>

</dictionary>

and

$ lt-comp lr f.dix lr.bin 
main@standard 2 2
$ echo '^x<adj>$' | lt-proc -b lr.bin
Error: Invalid dictionary (hint: the left side of an entry is empty)

The printout shows why the binary is invalid:

$ lt-print lr.bin
0       1       x       x
1       0       <adj>   <adj>
0

ie. state "0" appears both as initial and final state. If we remove the <par n="eps"/>, we get the expected

$ lt-print lr.bin
0       1       x       x
1       2       <adj>   <adj>
2