@Override
public Pair<ILangExpression, VariableSubstitutionEnvironment> visit(FunctionDecl fd,
VariableSubstitutionEnvironment env) throws CompilationException {
List<VarIdentifier> newList = new ArrayList<>(fd.getParamList().size());
for (VarIdentifier vi : fd.getParamList()) {
VariableExpr varExpr = new VariableExpr(vi);
if (!env.constainsOldVar(varExpr)) {
throw new CompilationException(ErrorCode.COMPILATION_ERROR, fd.getSourceLocation(),
"Parameter " + vi + " does not appear in the substitution list.");
}
Expression newExpr = env.findSubstitution(varExpr);
if (newExpr.getKind() != Kind.VARIABLE_EXPRESSION) {
throw new CompilationException(ErrorCode.COMPILATION_ERROR, fd.getSourceLocation(),
"Parameter " + vi + " cannot be substituted by a non-variable expression.");
}
newList.add(((VariableExpr) newExpr).getVar());
}
Pair<ILangExpression, VariableSubstitutionEnvironment> p1 = fd.getFuncBody().accept(this, env);
FunctionDecl newF = new FunctionDecl(fd.getSignature(), newList, (Expression) p1.first);
newF.setSourceLocation(fd.getSourceLocation());
return new Pair<>(newF, env);
}