[augeas-devel] Fixing ambiguous iteration errors

[Tom Limoncelli]

Thanks for the help so far.  I took your advice and looked at json.aug
for inspiration.

The format of the file looks like lisp:

# comment (always starts on column 0)
(foo bar)
(foo 'bar')
(foo (bar bar bar))
(foo (bar bar
  bar))

# Blank lines also permitted

Currently I keep getting:
Syntax error in lens definition
./xendconfsxp.aug:31.0-.50:Failed to compile lns
./xendconfsxp.aug:31.12-.30:exception: overlapping lenses in tree union.put
    Example matched by both:
    First lens: ./xendconfsxp.aug:29.12-.55:
    Second lens: ./xendconfsxp.aug:16.17-.36:

The example is blank.  I'm not sure if that means "\n" or "" or if
this is a bug.

Here's the module:

     1	module Xendconfsxp =
     2	  autoload xfm
     3	
     4	let spc1 = /[ \t\n]+/
     5	let ws = del spc1 " "
     6	
     7	let lbrack = del /\([ \t\n]*/ "("
     8	let rbrack = del /[ \t\n]*\)/ ")"
     9	
    10	(*
    11	 First attempt which didn't work. Commenting this out and using
more simple one for now.
    12	let no_ws_comment =
    13	    [ label "#comment" . del /#[ \t]*/ "# "
    14	        . store /[^ \t]+[^\n]*/ . del /\n/ "\n" ]
    15	*)
    16	let empty_line = del /[ \t]*\n/ "\n"
    17	let no_ws_comment = del /#[^\n]*\n/ "#\n"
    18	
    19	let var_name = key Rx.word
    20	(* Either a word or a quoted string *)
    21	let str_store = store /[A-Za-z0-9_.-]+|\"([^\"\\\\]|(\\\\.))*\"/
    22	let str = [ label "string" . str_store ]
    23	
    24	let rec thing =
    25	    let array = [ label "array" . lbrack . Build.list thing ws
. rbrack ] in
    26	    let str = [ label "item" . str_store ] in
    27	    str | array
    28	
    29	let sexpr = lbrack . [ var_name . ws . thing ] . rbrack
    30	
    31	let lns = ( sexpr | empty_line | no_ws_comment ) *
    32	
    33	let filter = incl "xend-config.sxp" . Util.stdexcl
    34	let xfm = transform lns filter

The actual files are here:
http://whatexit.org/tal/augeas/3/xendconfsxp.aug.txt
http://whatexit.org/tal/augeas/3/test_xendconfsxp.aug.txt

I can narrow the problem down to an even more simple case.  At least I
think this is the same:

module Foo =
  let ws = del /[ \t\n]+/ " "
  let a = key /a+/
  let b = [ label "b" . store /b+/ ]
  let lns = ws | a | b

  test lns get "aaa bbb " = ?

$ /usr/local/bin/augparse foo.aug
Syntax error in lens definition
foo.aug:5.2-.22:Failed to compile lns
foo.aug:5.12-.18:exception: overlapping lenses in tree union.put
    Example matched by both:
    First lens: foo.aug:2.11-.29:
    Second lens: foo.aug:3.10-.18:


I'm unclear what I'm doing wrong.  Suggestions?

Thanks in advance!
Tom