Possible compiler error when using the foreach construct

[Casey Casalnuovo]

While testing out queries on Boa I came across a case where looping over the values of a map with the foreach construct produced a compile error with no message.  However, when I altered the program to the equivalent for statement (as described in the documentation here: http://boa.cs.iastate.edu/docs/quantifiers.php) the program compiled and ran.  I've simplified the programs a bit to give a more minimal test case to reproduce the error.  I've attached a version that compiles and runs (noCompileError.boa) and one that fails to compile (compileError.boa) when running on the 2015 Github/Small dataset.  From my understanding, these programs should behave identically.

Is this an error in how the compiler handles the foreach structure, or have I misunderstood the documentation?

[Robert E Dyer]

Hi Casey,

Indeed you seem to have hit a compile error.  Essentially, the foreach you wrote is doing an implicit ‘def()’ around the condition (to make that expression into a boolean).  And it appears that calling ‘def(auth_array[i])’ generates some strange Java code of the form auth_array[i] != null.  This fails to compile (with javac) because the LHS is a long.

I filed this as a new issue with the compiler, which you can see here:

https://github.com/boalang/compiler/issues/68

- Robert

On Oct 5, 2016, at 2:43 PM, Casey Casalnuovo <cca...@ucdavis.edu> wrote:

<compileError.boa>

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Robert Dyer | Assistant Professor | Department of Computer Science
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[Casey Casalnuovo]

Okay, thank you.  Hopefully you can fix it without too much trouble.