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Cannot process string literals and references as operands in ConditionComparison

In two cases where ConditionComparison is used, there is ambiguity in the grammar and then in the interpreter affecting using string literals and references as operands. They are parsed and then interpreted as column names. In case of Calculator type, this leads to a crash with key error (see two minimal examples below). Numerical and boolean literals work as expected.

Input:

calc = Calculator vasp == 5.4.4 (
        (algo: 'Fast', 'VeryFast'),
        (encut: 400.0, 350.) [eV]
)

limit = 350 [eV]
calc_1 = calc where encut > limit
print(calc_1)

Output:

Traceback (most recent call last):
  File "python-3.10.12/lib/python3.10/site-packages/pandas/core/indexes/base.py", line 3805, in get_loc
    return self._engine.get_loc(casted_key)
  File "index.pyx", line 167, in pandas._libs.index.IndexEngine.get_loc
  File "index.pyx", line 196, in pandas._libs.index.IndexEngine.get_loc
  File "pandas/_libs/hashtable_class_helper.pxi", line 7081, in pandas._libs.hashtable.PyObjectHashTable.get_item
  File "pandas/_libs/hashtable_class_helper.pxi", line 7089, in pandas._libs.hashtable.PyObjectHashTable.get_item
KeyError: 'limit'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "python-3.10.12/bin/texts", line 8, in <module>
    sys.exit(texts())
  File "vre-language/src/virtmat/language/cli/__init__.py", line 28, in texts
    clargs.func(clargs)
  File "vre-language/src/virtmat/language/cli/run_model.py", line 156, in main
    evaluate_prog(prog)
  File "vre-language/src/virtmat/language/utilities/errors.py", line 304, in wrapper
    process_error(err)
  File "vre-language/src/virtmat/language/utilities/errors.py", line 292, in process_error
    raise err.__cause__
  File "vre-language/src/virtmat/language/utilities/errors.py", line 207, in wrapper
    return func(*args, **kwargs)
  File "vre-language/src/virtmat/language/utilities/typemap.py", line 117, in wrapper
    return checktype_(func(obj), obj.type_)
  File "vre-language/src/virtmat/language/interpreter/instant_executor.py", line 52, in program_value
    vals = [p.value for p in get_children_of_type('Print', self) if p.value]
  File "vre-language/src/virtmat/language/interpreter/instant_executor.py", line 52, in <listcomp>
    vals = [p.value for p in get_children_of_type('Print', self) if p.value]
  File "vre-language/src/virtmat/language/utilities/errors.py", line 304, in wrapper
    process_error(err)
  File "vre-language/src/virtmat/language/utilities/errors.py", line 292, in process_error
    raise err.__cause__
  File "vre-language/src/virtmat/language/utilities/errors.py", line 207, in wrapper
    return func(*args, **kwargs)
  File "vre-language/src/virtmat/language/utilities/typemap.py", line 117, in wrapper
    return checktype_(func(obj), obj.type_)
  File "vre-language/src/virtmat/language/interpreter/instant_executor.py", line 417, in condition_comparison_value
    column_right = qobj_ref_val[self.column_right] if self.column_right else None
  File "vre-language/src/virtmat/language/utilities/amml.py", line 339, in __getitem__
    return super().__getitem__(key)
  File "vre-language/src/virtmat/language/utilities/amml.py", line 308, in __getitem__
    return self.parameters[key]
  File "python-3.10.12/lib/python3.10/site-packages/pandas/core/frame.py", line 4102, in __getitem__
    indexer = self.columns.get_loc(key)
  File "python-3.10.12/lib/python3.10/site-packages/pandas/core/indexes/base.py", line 3812, in get_loc
    raise KeyError(key) from err
KeyError: 'limit'

Input:

calc = Calculator vasp == 5.4.4 (
        (algo: 'Fast', 'VeryFast'),
        (encut: 400.0, 350.) [eV]
)

calc_2 = calc where algo == 'Fast'
print(calc_2)

Output:

Traceback (most recent call last):
  File "python-3.10.12/lib/python3.10/site-packages/pandas/core/indexes/base.py", line 3805, in get_loc
    return self._engine.get_loc(casted_key)
  File "index.pyx", line 167, in pandas._libs.index.IndexEngine.get_loc
  File "index.pyx", line 196, in pandas._libs.index.IndexEngine.get_loc
  File "pandas/_libs/hashtable_class_helper.pxi", line 7081, in pandas._libs.hashtable.PyObjectHashTable.get_item
  File "pandas/_libs/hashtable_class_helper.pxi", line 7089, in pandas._libs.hashtable.PyObjectHashTable.get_item
KeyError: 'Fast'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "python-3.10.12/bin/texts", line 8, in <module>
    sys.exit(texts())
  File "vre-language/src/virtmat/language/cli/__init__.py", line 28, in texts
    clargs.func(clargs)
  File "vre-language/src/virtmat/language/cli/run_model.py", line 156, in main
    evaluate_prog(prog)
  File "vre-language/src/virtmat/language/utilities/errors.py", line 304, in wrapper
    process_error(err)
  File "vre-language/src/virtmat/language/utilities/errors.py", line 292, in process_error
    raise err.__cause__
  File "vre-language/src/virtmat/language/utilities/errors.py", line 207, in wrapper
    return func(*args, **kwargs)
  File "vre-language/src/virtmat/language/utilities/typemap.py", line 117, in wrapper
    return checktype_(func(obj), obj.type_)
  File "vre-language/src/virtmat/language/interpreter/instant_executor.py", line 52, in program_value
    vals = [p.value for p in get_children_of_type('Print', self) if p.value]
  File "vre-language/src/virtmat/language/interpreter/instant_executor.py", line 52, in <listcomp>
    vals = [p.value for p in get_children_of_type('Print', self) if p.value]
  File "vre-language/src/virtmat/language/utilities/errors.py", line 304, in wrapper
    process_error(err)
  File "vre-language/src/virtmat/language/utilities/errors.py", line 292, in process_error
    raise err.__cause__
  File "vre-language/src/virtmat/language/utilities/errors.py", line 207, in wrapper
    return func(*args, **kwargs)
  File "vre-language/src/virtmat/language/utilities/typemap.py", line 117, in wrapper
    return checktype_(func(obj), obj.type_)
  File "vre-language/src/virtmat/language/interpreter/instant_executor.py", line 417, in condition_comparison_value
    column_right = qobj_ref_val[self.column_right] if self.column_right else None
  File "vre-language/src/virtmat/language/utilities/amml.py", line 339, in __getitem__
    return super().__getitem__(key)
  File "vre-language/src/virtmat/language/utilities/amml.py", line 308, in __getitem__
    return self.parameters[key]
  File "python-3.10.12/lib/python3.10/site-packages/pandas/core/frame.py", line 4102, in __getitem__
    indexer = self.columns.get_loc(key)
  File "python-3.10.12/lib/python3.10/site-packages/pandas/core/indexes/base.py", line 3812, in get_loc
    raise KeyError(key) from err
KeyError: 'Fast'

If we replace the Calculator with Table:

calc = (
        (lreal: true, false),
        (encut: 400.0, 350.) [eV]
)

limit = 350 [eV]
calc_1 = calc where encut > limit
print(calc_1)

we get this error message:

Value error: /mnt/data/ubuntu/work/vre-language/examples/8.vm:7:21 --> encut > limit <--
column "limit" not found in Table "calc"

which is basically the same problem. The lack of static check in Calculator causes a crash at run time. Similarly,

calc = (
        (algo: 'Fast', 'VeryFast'),
        (encut: 400.0, 350.) [eV]
)

calc_1 = calc where algo == 'Fast'
print(calc_1)

causes:

Value error: /mnt/data/ubuntu/work/vre-language/examples/8.vm:6:21 --> algo == 'Fast' <--
column "Fast" not found in Table "calc"

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