%nonassoc IF
%nonassoc ELSE

%%

ifelse:
    | IF cond = expr left = statement
    { STMT_If { loc = mkLocation $startpos
              ; cond = cond
              ; then_branch = left
              ; else_branch = None
              }}

    | IF cond = expr left = statement ELSE right = statement
    { STMT_If { loc = mkLocation $startpos
              ; cond = cond
              ; then_branch = left
              ; else_branch = Some right
              }}