Allow back “residual” as symbol name

Commit 8c021084 had removed the possibility of
using “residual” as a variable name. In particular, this broke the
lmmcp/rbc.mod test.

src/DynareBison.yy

@@ -124,7 +124,7 @@ str_tolower(string s)
 %token POSTERIOR_MAX_SUBSAMPLE_DRAWS MIN MINIMAL_SOLVING_PERIODS
 %token MODE_CHECK MODE_CHECK_NEIGHBOURHOOD_SIZE MODE_CHECK_SYMMETRIC_PLOTS MODE_CHECK_NUMBER_OF_POINTS MODE_COMPUTE MODE_FILE MODEL MODEL_COMPARISON MODEL_INFO MSHOCKS ABS SIGN
 %token MODEL_DIAGNOSTICS MODIFIEDHARMONICMEAN MOMENTS_VARENDO CONTEMPORANEOUS_CORRELATION DIFFUSE_FILTER SUB_DRAWS TAPER_STEPS GEWEKE_INTERVAL RAFTERY_LEWIS_QRS RAFTERY_LEWIS_DIAGNOSTICS BROOKS_GELMAN_PLOTROWS MCMC_JUMPING_COVARIANCE MOMENT_CALIBRATION
-%token NUMBER_OF_PARTICLES RESAMPLING SYSTEMATIC GENERIC RESAMPLING_THRESHOLD RESAMPLING_METHOD KITAGAWA STRATIFIED RESIDUAL SMOOTH
+%token NUMBER_OF_PARTICLES RESAMPLING SYSTEMATIC GENERIC RESAMPLING_THRESHOLD RESAMPLING_METHOD KITAGAWA STRATIFIED SMOOTH
 %token CPF_WEIGHTS AMISANOTRISTANI MURRAYJONESPARSLOW WRITE_EQUATION_TAGS FILTER_INITIAL_STATE
 %token NONLINEAR_FILTER_INITIALIZATION FILTER_ALGORITHM PROPOSAL_APPROXIMATION CUBATURE UNSCENTED MONTECARLO DISTRIBUTION_APPROXIMATION
 %token <string> NAME
@@ -173,7 +173,7 @@ str_tolower(string s)
 %token VLISTLOG VLISTPER SPECTRAL_DENSITY INIT2SHOCKS
 %token RESTRICTION RESTRICTION_FNAME CROSS_RESTRICTIONS NLAGS CONTEMP_REDUCED_FORM REAL_PSEUDO_FORECAST
 %token DUMMY_OBS NSTATES INDXSCALESSTATES NO_BAYESIAN_PRIOR SPECIFICATION SIMS_ZHA
-%token <string> ALPHA BETA ABAND NINV CMS NCMS CNUM GAMMA INV_GAMMA INV_GAMMA1 INV_GAMMA2 NORMAL UNIFORM EPS PDF FIG DR NONE PRIOR PRIOR_VARIANCE HESSIAN IDENTITY_MATRIX DIRICHLET DIAGONAL OPTIMAL MFS
+%token <string> ALPHA BETA ABAND NINV CMS NCMS CNUM GAMMA INV_GAMMA INV_GAMMA1 INV_GAMMA2 NORMAL UNIFORM EPS PDF FIG DR NONE PRIOR PRIOR_VARIANCE HESSIAN IDENTITY_MATRIX DIRICHLET DIAGONAL OPTIMAL MFS RESIDUAL
 %token GSIG2_LMDM Q_DIAG FLAT_PRIOR NCSK NSTD WEIBULL WEIBULL_PDF
 %token INDXPARR INDXOVR INDXAP APBAND INDXIMF INDXFORE FOREBAND INDXGFOREHAT INDXGIMFHAT
 %token INDXESTIMA INDXGDLS EQ_MS FILTER_COVARIANCE UPDATED_COVARIANCE FILTER_DECOMPOSITION SMOOTHED_STATE_UNCERTAINTY SMOOTHER_REDUX
@@ -4647,6 +4647,7 @@ symbol : NAME
        | ADD
        | MULTIPLY
        | MFS
+       | RESIDUAL
        ;
 
 %%

src/DynareFlex.ll

@@ -419,7 +419,10 @@ DATE -?[0-9]+([ya]|m([1-9]|1[0-2])|q[1-4]|[sh][12])
 <DYNARE_STATEMENT>kitagawa {return token::KITAGAWA;}
 <DYNARE_STATEMENT>smooth {return token::SMOOTH;}
 <DYNARE_STATEMENT>stratified {return token::STRATIFIED;}
-<DYNARE_STATEMENT>residual {return token::RESIDUAL;}
+<DYNARE_STATEMENT>residual {
+  yylval->emplace<string>(yytext);
+  return token::RESIDUAL;
+}
 <DYNARE_STATEMENT>cpf_weights {return token::CPF_WEIGHTS;}
 <DYNARE_STATEMENT>amisanotristani {return token::AMISANOTRISTANI;}
 <DYNARE_STATEMENT>murrayjonesparslow {return token::MURRAYJONESPARSLOW;}