Bug introduced in 0c755460, that manifested on the Gitlab runners.

Note that there is no equivalent of boost::filesystem::unique_path(), so I
implemented ModFile::unique_path() which does something similar.

stop processing when certain functions are used in a linear context on endogenous/exogenous variables. closes dynare#1537

#26

closes #26

closes #28

Not necessary because of parser rules for function definition

— allow “language=matlab” for symmetry (this is the default)
— remove the useless “cuda” and “python” values
— give a more meaningful error message when “output” is used in conjunction
  with “language=matlab”

In that case, the preprocessor outputs g4 (4th derivatives of model) and
g3p (1st derivs of g3 w.r.t. parameters).

Ref #10

The transformation would be incorrect because of the expectation operator.

There was already a safety check, but it was not entirely correct. For example,
if “exp(y)” was appearing before “exp(y(+1))”, the check would not catch the
problem, because it happened after the substitution table had been filled. So
we now do the check before filling that table.

By the way, do some small code simplifications.

Useless copies are thus avoided in some situations.