Allow model-local variables with leads or lags

Closes: #1929

doc/manual/source/the-model-file.rst

@@ -962,7 +962,10 @@ The model is declared inside a ``model`` block:
     equal sign, and the expression for which this new variable will
     stand. Later on, every time this variable appears in the model,
     Dynare will substitute it by the expression assigned to the
-    variable. Note that the scope of this variable is restricted to
+    variable (if the model-local variable appears with a lead or a lag
+    attached to it between parenthesis, the substitution will be done by
+    shifting the expression accordingly).
+    Note that the scope of this variable is restricted to
     the model block; it cannot be used outside. To assign a LaTeX name
     to the model local variable, use the declaration syntax outlined
     by :comm:`model_local_variable`. A model local variable declaration

preprocessor @ 84d792bc

-Subproject commit 31080eed6ce6c623863850d4e2da5f8317f2b5d0
+Subproject commit 84d792bced340c52d90cd962e51e22eec605cea0

tests/preprocessor_checks/example1_mlv.mod

-// Tests for model local variables
-// (including in params derivs file, i.e. with identification, see Dynare/preprocessor#13)
+/* Tests for model-local variables
+  (including in params derivs file, i.e. with identification, see Dynare/preprocessor#13)
+   Also tests the possibility of having a lead/lag on a model-local variable
+  (recursively in the definition of another such variable) (see #1929)
+*/
 
 var c, y, k, a, h, b;
 varexo e, u;
@@ -22,8 +25,8 @@ phi   = 0.1;
 model_local_variable foo $\text{foo}$;
 
 model;
-#bar = exp(b)*c;
-#foo = bar/(exp(b(+1))*c(+1));
+#bar = exp(b(+1))*c(+1);
+#foo = bar(-1)/(exp(b(+1))*c(+1));
 c*theta*h^(1+psi)=(1-alpha)*y;
 k = beta*(foo
     *(exp(b(+1))*alpha*y(+1)+(1-delta)*k));