<div dir="ltr">Hi, I'm working on a lens that has two errors: >> 1 (* >> 2 # example configuration follows: >> 3 # default = value >> 4 key = value >> 5 >> 6 # default = value # inline comment >> 7 key = value # inline comment >> 8 *) >> 9 >> 10 (* >> 11 # key/value formats: >> 12 >> 13 keys >> 14 [a-z_] >> 15 >> 16 values >> 17 boolean: true/false >> 18 int 0, 100 >> 19 real 3.0 >> 20 hex int ffeedd >> 21 string "..." >> 22 unquoted string sdl, f, f2 >> 23 *) >> 24 >> 25 (* >> 26 # quoted string regex scratchpad >> 27 quoted string regex = >> 28 good: >> 29 "asdf\"qwer" >> 30 "asdf\\qwer" >> 31 "asdf\\\\\"qwer" >> 32 bad: >> 33 "asdf\\"qwer" >> 34 "asdf\\\\\\"qwer" >> 35 >> 36 /.*/ - /.*(\\)*[^\]".*/ >> 37 >> 38 /([^"](\")?)*/ >> 39 *) >> 40 >> 41 module ConfigObj = >> 42 let _ = print_regexp /"/ >> 43 let _ = print_string "\n" >> 44 let var0 = "\"" >> 45 let _ = print_string (var0 . "\n") >> 46 let _ = print_string "\n" >> 47 >> 48 let var1 = "\"asdf\\\\\\\\"qwer\"" >> 49 let _ = print_string (var1 . "\n") >> 50 let _ = print_string ((regexp_match (/\".*\"/ - /\"(.*[^\])?([\]{2})*".*\"/) var1) . "\n") >> 51 >> 52 let option = key /[a-z]([a-z_]*[a-z])?/ >> 53 let value_bool = store /(true|false)/ . [ label "type" . value "bool" ] >> 54 let value_int = store /(0|[1-9][0-9]*)/ . [ label "type" . value "int" ] >> 55 let value_decimal = store ((lens_ctype value_int) . /\.[0-9]+/) . [ label "type" . value "decimal" ] >> 56 let value_string = (del "\"" "\"") . (store (/.*/ - /(.*[^\]|)([\]{2})*".*/)) . (del "\"" "\"") . [ label "type" . value "string" ] >> 57 let value_all = value_bool | value_int | value_decimal >> 58 let sep_assign = del /[ \t]*=[ \t]*/ " = " >> 59 let sep_comment = del /[ \t]*#[ \t]*/ " # " >> 60 let record_comment = [ label "comment" . sep_comment . store /([^ \t\n].*)?/ ] >> 61 let record = option . sep_assign . value_all . record_comment? >> 62 let record_not = label "comment" . store (/([^ \t\n].*)?/ - lens_ctype record) >> 63 let comment = del /#[ \t]*/ "# " . ( [ record . [ label "commented" ] ] | [ record_not ] ) >> 64 let line = del /[ \t]*/ "" . ( comment | [ record ] ) . del "\n" "\n" >> 65 let lns = line * The first is a regex problem: I want to match double-quoted c-style strings, ie strings with escape sequences such as "\"", "\\\"" and so on. The regex I've crafted (line#50) evidently fits the bill - try modifying the input test values (line#48) to verify - so I don't understand why the derived lens (line#56) is failing, and thereby causing this "ambiguous concatenation" error: >> Syntax error in lens definition >> configobj.aug:61.4-.75:Failed to compile record >> configobj.aug:61.26-.75:exception: ambiguous concatenation >> First regexp: /([a-z]([a-z_]*[a-z])?)([ \t]*=[ \t]*)((((true|false)))|(((0|[1-9][0-9]*)))|(((((0|[1-9][0-9]*)))(\\.[0-9]+)))|((")(([^\n"\\][^\n"\\]*\\\\|\\\\)([^\n\\][^\n"\\]*\\\\)*\\\\(([^\n"\\][^\n"\\]*\\\\|\\\\)([^\n\\][^\n"\\]*\\\\)*\\\\)*(([^\n"\\][^\n"\\]*\\\\|\\\\)([^\n\\][^\n"\\]*\\\\)*([^\n\\][^\n"\\]*|)|[^\n"\\][^\n"\\]*|)|([^\n"\\][^\n"\\]*\\\\|\\\\)([^\n\\][^\n"\\]*\\\\)*([^\n\\][^\n"\\]*|)|[^\n"\\][^\n"\\]*|)(")))/ >> Second regexp: /(([ \t]*#[ \t]*)(([^ \t\n].*)?))?/ >> 'a="\\"#"' can be split into >> 'a="\\"|=|#"' >> >> and >> 'a="\\"#"|=|' <----- not possible per the regex >> >> First lens: configobj.aug:61.26-.57: >> Second lens: configobj.aug:61.60-.75: The second problem - you'll see if the first is fixed - is a limitation of augeas' tree-text conversion, the inability to differentiate trees on depth. This generates the error "exception: overlapping lenses in tree union.put" and crops up in two locations: '[ record . [ label "commented" ] ]' (line#63) ----vs---- '[ record_not ]' (line#63) ::: The "record_not" label of "comment" is also a possible valid label of the "record" lens [line#52]. Hacky workaround is to change the label to an invalid key, ie "comment2", etc. '[ record . [ label "commented" ] ]' (line#63) ----vs---- '[ record ]' (line#64) ::: Unlike previous, no hacky workaround. Obviously this can be fixed by scanning the *depth* of the tree. In both cases, one branch is guaranteed to have a subnode with the label "commented" unlike the other. While augeas doesn't implement this, there was a suggestion on the mailing list regarding a lens-based workaround[1] that I didn't understand. I'd appreciate if someone could provide a concrete example for my case. Sincerely, [1] <a href="https://www.redhat.com/archives/augeas-devel/2009-June/msg00088.html">https://www.redhat.com/archives/augeas-devel/2009-June/msg00088.html</a> </div>