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ruby--ruby/ext/ripper/tools/dsl.rb

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# Simple DSL implementation for Ripper code generation
#
# input: /*% ripper: stmts_add(stmts_new, void_stmt) %*/
# output:
# VALUE v1, v2;
# v1 = dispatch0(stmts_new);
# v2 = dispatch0(void_stmt);
# $$ = dispatch2(stmts_add, v1, v2);
class DSL
def initialize(code, options)
@events = {}
@error = options.include?("error")
@brace = options.include?("brace")
if options.include?("final")
@final = "p->result"
else
@final = (options.grep(/\A\$[$\d]\z/)[0] || "$$")
end
@vars = 0
# create $1 == "$1", $2 == "$2", ...
re, s = "", ""
1.upto(9) do |n|
re << "(..)"
s << "$#{ n }"
end
/#{ re }/ =~ s
# struct parser_params *p
p = "p"
@code = ""
@last_value = eval(code)
end
attr_reader :events
undef lambda
undef hash
undef class
def generate
s = "#@code#@final=#@last_value;"
s = "{VALUE #{ (1..@vars).map {|v| "v#{ v }" }.join(",") };#{ s }}" if @vars > 0
s << "ripper_error(p);" if @error
s = "{#{ s }}" if @brace
"\t\t\t#{s}"
end
def new_var
"v#{ @vars += 1 }"
end
def opt_event(event, default, addend)
add_event(event, [default, addend], true)
end
def add_event(event, args, qundef_check = false)
event = event.to_s.sub(/!\z/, "")
@events[event] = args.size
vars = []
args.each do |arg|
vars << v = new_var
@code << "#{ v }=#{ arg };"
end
v = new_var
d = "dispatch#{ args.size }(#{ [event, *vars].join(",") })"
d = "#{ vars.last }==Qundef ? #{ vars.first } : #{ d }" if qundef_check
@code << "#{ v }=#{ d };"
v
end
def method_missing(event, *args)
if event.to_s =~ /!\z/
add_event(event, args)
elsif args.empty? and /\Aid[A-Z_]/ =~ event.to_s
event
else
"#{ event }(#{ args.join(", ") })"
end
end
def self.const_missing(name)
name
end
end