Hello,
I am new to Treetop : in the following example, I’d like to get an
AST, but I am having troubles with Treetop::Runtime::SyntaxNode. I
though I was manipulating my own ast types instead…
It is probably very awkward.
Can someone help ?
Thanks
JC
ruby FoobarCompiler.rb gives :
test 0 : parsing aa:1,2,3,14
-Success for parsing
-top level AST instanceof : Program
./ast.rb:8:in print': private methodprint’ called for
#Treetop::Runtime::SyntaxNode:0xb7d70db8 (NoMethodError)
from ./ast.rb:8:in map' from ./ast.rb:8:inprint’
from FoobarCompiler.rb:18:in parse' from FoobarCompiler.rb:27:intest’
from FoobarCompiler.rb:40
========treetop grammar for things like " aa:1,2,3,4" =============
require ‘ast’
grammar Foobar
rule program
ws lit ‘:’ num tail:(’,’ num)*
{
def build
Program.new all
end
def all
[lit] + [num.build] + tail.elements.map {|e| e.num.build}
end
}
end
rule lit
[a-z]+
{
def build
Lit.new(“foo”)
end
}
end
rule num
[0-9]+
{
def build
Num.new(text_value)
end
}
end
rule ws
[ \n\t]*
end
end
#==========================================================
class FoobarCompiler
def initialize
@parser = FoobarParser.new
end
def parse(txt)
[email protected](txt)
if root
puts “\t-Success for parsing”
@[email protected](txt).build
puts “\t-top level AST instanceof : #{@tree.class}”
@tree.print
else
puts “Failure for parsing : #{@parser.failure_message}”
end
end
def test num,goal,txt
puts “test #{num}”.ljust(7)+" : #{goal} ".ljust(50)
parse txt
end
end
program_0 = “aa:1,2,3,14”
c=FoobarCompiler.new()
c.test 0, “parsing #{program_0}”, program_0
#=====ast.rb ==============
include Treetop::Runtime
class Ast < Treetop::Runtime::SyntaxNode
def initialize(sub=nil)
@subtrees=sub
end
def print
puts @subtrees.map{|t| t.print}
end
end
class Program < Ast
def initialize(subt=nil)
super(subt)
end
end
class Num < Ast
def initialize(val)
super
@val=val
end
def print
"value=#{@val}"
end
end
class Lit < Ast
def initialize(val)
super
@txt=val
end
def print
“literal=#{@txt}”
end
end