+
+## ---------------- ##
+## api.value.type. ##
+## ---------------- ##
+
+
+# ---------------------- #
+# api.value.type=union. #
+# ---------------------- #
+
+# b4_symbol_type_register(SYMBOL-NUM)
+# -----------------------------------
+# Symbol SYMBOL-NUM has a type (for variant) instead of a type-tag.
+# Extend the definition of %union's body (b4_union_members) with a
+# field of that type, and extend the symbol's "type" field to point to
+# the field name, instead of the type name.
+m4_define([b4_symbol_type_register],
+[m4_define([b4_symbol($1, type_tag)],
+ [b4_symbol_if([$1], [has_id],
+ [b4_symbol([$1], [id])],
+ [yytype_[]b4_symbol([$1], [number])])])dnl
+m4_append([b4_union_members],
+m4_expand([
+ b4_symbol_tag_comment([$1])dnl
+ b4_symbol([$1], [type]) b4_symbol([$1], [type_tag]);]))
+])
+
+
+# b4_type_define_tag(SYMBOL1-NUM, ...)
+# ------------------------------------
+# For the batch of symbols SYMBOL1-NUM... (which all have the same
+# type), enhance the %union definition for each of them, and set
+# there "type" field to the field tag name, instead of the type name.
+m4_define([b4_type_define_tag],
+[b4_symbol_if([$1], [has_type],
+ [m4_map([b4_symbol_type_register], [$@])])
+])
+
+
+# b4_symbol_value_union(VAL, [TYPE])
+# ----------------------------------
+# Same of b4_symbol_value, but when api.value.type=union.
+m4_define([b4_symbol_value_union],
+[m4_ifval([$2],
+ [(*($2*)(&$1))],
+ [$1])])
+])
+
+
+# b4_value_type_setup_union
+# -------------------------
+# Setup support for api.value.type=union. Symbols are defined with a
+# type instead of a union member name: build the corresponding union,
+# and give the symbols their tag.
+m4_define([b4_value_type_setup_union],
+[m4_define([b4_union_members])
+b4_type_foreach([b4_type_define_tag])
+m4_copy_force([b4_symbol_value_union], [b4_symbol_value])
+])
+
+
+# -------------------------- #
+# api.value.type = variant. #
+# -------------------------- #
+
+# b4_value_type_setup_variant
+# ---------------------------
+# Setup support for api.value.type=variant. By default, fail, specialized
+# by other skeletons.
+m4_define([b4_value_type_setup_variant],
+[b4_complain_at(b4_percent_define_get_loc([[api.value.type]]),
+ [['%s' does not support '%s']],
+ [b4_skeleton],
+ [%define api.value.type variant])])
+
+
+# _b4_value_type_setup_keyword
+# ----------------------------
+# api.value.type is defined with a keyword/string syntax. Check if
+# that is properly defined, and prepare its use.
+m4_define([_b4_value_type_setup_keyword],
+[b4_percent_define_check_values([[[[api.value.type]],
+ [[none]],
+ [[union]],
+ [[union-directive]],
+ [[variant]],
+ [[yystype]]]])dnl
+m4_case(b4_percent_define_get([[api.value.type]]),
+ [union], [b4_value_type_setup_union],
+ [variant], [b4_value_type_setup_variant])])
+
+
+# b4_value_type_setup
+# -------------------
+# Check if api.value.type is properly defined, and possibly prepare
+# its use.
+b4_define_silent([b4_value_type_setup],
+[# Define default value.
+b4_percent_define_ifdef([[api.value.type]], [],
+[# %union => api.value.type=union-directive
+m4_ifdef([b4_union_members],
+[m4_define([b4_percent_define_kind(api.value.type)], [keyword])
+m4_define([b4_percent_define(api.value.type)], [union-directive])],
+[# no tag seen => api.value.type={int}
+m4_if(b4_tag_seen_flag, 0,
+[m4_define([b4_percent_define_kind(api.value.type)], [code])
+m4_define([b4_percent_define(api.value.type)], [int])],
+[# otherwise api.value.type=yystype
+m4_define([b4_percent_define_kind(api.value.type)], [keyword])
+m4_define([b4_percent_define(api.value.type)], [yystype])])])])
+
+# Set up.
+m4_bmatch(b4_percent_define_get_kind([[api.value.type]]),
+ [keyword\|string], [_b4_value_type_setup_keyword])
+])
+
+
projects / bison.git / blobdiff