+# b4_parse_assert_if([IF-ASSERTIONS-ARE-USED], [IF-NOT])
+# b4_parse_trace_if([IF-DEBUG-TRACES-ARE-ENABLED], [IF-NOT])
+# b4_token_ctor_if([IF-YYLEX-RETURNS-A-TOKEN], [IF-NOT])
+# ----------------------------------------------
+b4_percent_define_if_define([token_ctor], [api.token.constructor])
+b4_percent_define_if_define([locations]) # Whether locations are tracked.
+b4_percent_define_if_define([parse.assert])
+b4_percent_define_if_define([parse.trace])
+
+
+# b4_bison_locations_if([IF-TRUE])
+# --------------------------------
+# Expand IF-TRUE if using locations, and using the default location
+# type.
+m4_define([b4_bison_locations_if],
+[b4_locations_if([b4_percent_define_ifdef([[api.location.type]], [], [$1])])])
+
+
+# b4_error_verbose_if([IF-ERRORS-ARE-VERBOSE], [IF-NOT])
+# ------------------------------------------------------
+# Map %define parse.error "(simple|verbose)" to b4_error_verbose_if and
+# b4_error_verbose_flag.
+b4_percent_define_default([[parse.error]], [[simple]])
+b4_percent_define_check_values([[[[parse.error]],
+ [[simple]], [[verbose]]]])
+m4_define([b4_error_verbose_flag],
+ [m4_case(b4_percent_define_get([[parse.error]]),
+ [simple], [[0]],
+ [verbose], [[1]])])
+b4_define_flag_if([error_verbose])
+
+# yytoken_table is needed to support verbose errors.
+b4_error_verbose_if([m4_define([b4_token_table_flag], [1])])
+
+
+# b4_variant_if([IF-VARIANT-ARE-USED], [IF-NOT])
+# ----------------------------------------------
+b4_percent_define_if_define([variant])
+m4_case(b4_percent_define_get([[api.value.type]]),
+ [variant], [m4_define([b4_variant_flag], [[1]])],
+ [m4_define([b4_variant_flag], [[0]])])
+b4_define_flag_if([variant])