class Opal::Fragment

aka, source-maps!
mapping can be created of the original location => target location,
it was generated. Using this sexp, when writing fragments in order, a
to the destination. It also keeps hold of the original sexp from which
A fragment holds a string of generated javascript that will be written

def column 

def column
  @sexp.column if @sexp
end

def initialize(code, sexp = nil) 

def initialize(code, sexp = nil)
  @code = code.to_s
  @sexp = sexp
end

def inspect

inspect the contents of this fragment, f("fooo") 
def inspect
  "f(#{@code.inspect})"
end

def line 

def line
  @sexp.line if @sexp
end

def to_code

In debug mode we may wish to include the original line as a comment 
def to_code
  if @sexp
    "/*:#{@sexp.line}:#{@sexp.column}*/#{@code}"
  else
    @code
  end
end