Incorrect code generated for apply-to-all lookup definitions

[chrispcampbell]

Currently the transpiler will generate incorrect code for an "apply-to-all" lookup definition, that is, a lookup definition where the lookup data is the same for all subscripts in a dimension (aka subscript range). This is not a common case because it is not too useful to define a lookup like this (since you can get the same effect by defining the lookup without the dimension(s) on the LHS), but it sometimes comes up in practice if the lookup is added as a placeholder until subscript-specific lookups are defined at a later time.

For example:

DimA: A1, A1 ~~|
x[DimA]( (0,10), (1,20) ) ~~|
y[DimA] = x[DimA](1) ~~|

Currently the transpiler incorrectly generates a useless for loop at decl time:

for (let i = 0; i < 2; i++) {
  const _x_data__i_ = [0.0, 10.0, 1.0, 20.0];
}

And the init code references _x_data__i_ in a loop, which is fine, but I think the variable name could be simplified to just _x_data:

for (let i = 0; i < 2; i++) {
  _x[i] = fns.createLookup(2, _x_data__i_);
}

---

Workaround

The workaround is to define the lookup without dimensions:

DimA: A1, A1 ~~|
x( (0,10), (1,20) ) ~~|
y[DimA] = x(1) ~~|

---

Test case

This is not a high priority issue since there is a simple workaround, but we should fix this eventually since there's no reason that the transpiler should fail in this case (and I'd say it's OK if the generated code is not too efficient for this case).

Here is a failing unit test that I've added to a chris/642-apply-to-all-lookup-def branch to be addressed eventually:

  it('should work for lookup definition (1D, apply-to-all)', () => {
    const vars = readInlineModel(`
      DimA: A1, A2 ~~|
      x[DimA]( (0,10), (1,20) ) ~~|
    `)
    expect(vars.size).toBe(1)
    expect(genJS(vars.get('_x'), 'decl')).toEqual(['const _x_data = [0.0, 10.0, 1.0, 20.0];'])
    expect(genJS(vars.get('_x'), 'init-lookups')).toEqual([
      'for (let i = 0; i < 2; i++) {',
      '_x[i] = fns.createLookup(2, _x_data);',
      '}'
    ])
  })