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class PostProcessor
def initialize(source, out=STDOUT)
@out = out
@lines = File.readlines(source)
@index = -1
@case_bodies = {}
end
# Read/Unread with ability to push back one line for a single lookahead
def read
@index += 1
line = @last ? @last : @lines[@index]
@last = nil
line
end
def unread(line)
@index -= 1
@last = line
end
def end_of_actions?(line)
return line =~ %r{^//\s*ACTIONS_END}
end
def translate
while (line = read)
if line =~ %r{^//\s*ACTIONS_BEGIN}
translate_actions
elsif line =~ %r{^//\s*ACTION_BODIES}
generate_action_body_methods
else
@out.puts line
end
end
end
def generate_action_body_methods
@case_bodies.each { |label, code_body| generate_action_body_method(label, code_body) }
end
def generate_action_body_method(label, code_body)
@out.puts "public Object #{label}(Object yyVal, Object[] yyVals, int yyTop) {"
code_body.each { |line| @out.puts line }
@out.puts " return yyVal;"
@out.puts "}"
end
def translate_actions
count = 1
while (translate_action)
count += 1
end
end
# Assumptions:
# 1. no break; in our code. A bit weak, but this is highly specialized code.
# 2. All productions will have a line containing only { (with optional comment)
# 3. All productions will end with a line containly only } followed by break in ass 1.
def translate_action
line = read
return false if end_of_actions?(line) || line !~ /case\s+(\d+):/
case_number = $1
line = read
return false if line !~ /line\s+(\d+)/
line_number = $1
# Extra boiler plate '{' that we do not need
line = read
return false if line !~ /^\s*\{\s*(\/\*.*\*\/)?$/
label = "case#{case_number}_line#{line_number}"
@out.puts "case #{case_number}: yyVal = #{label}(yyVal, yyVals, yyTop); // line #{line_number}"
body = []
last_line = nil
while (line = read)
if line =~ /^\s*\}\s*$/ # Extra trailing boiler plate
next_line = read
if next_line =~ /break;/
@out.puts "break;"
break
else
body << line
unread next_line
end
else
body << line
end
end
@case_bodies[label] = body
true
end
end
PostProcessor.new(ARGV.shift).translate
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