diff options
Diffstat (limited to 'parser')
| -rw-r--r-- | parser/vyos1x_lexer.mll | 138 | ||||
| -rw-r--r-- | parser/vyos1x_parser.mly | 117 |
2 files changed, 0 insertions, 255 deletions
diff --git a/parser/vyos1x_lexer.mll b/parser/vyos1x_lexer.mll deleted file mode 100644 index a996642..0000000 --- a/parser/vyos1x_lexer.mll +++ /dev/null @@ -1,138 +0,0 @@ -{ - -open Vyos1x_parser - -exception Error of string - -(* - -The language of the VyOS 1.x config file has multiple ambiguities that -make it not even context free. - -The main issue is lack of explicit statement separators, so if we ignore whitespace, -a parser is left to guess if, for example - -address dhcp # leaf node with a value -disable # valueless leaf node - -is three valueless nodes, a valueless node followed by a node with a value, -or a node with a value followed by a valueless node. - -The only cue is the newline, which means that newlines are sometimes significant, -and sometimes they aren't. - -interfaces { # doesn't matter - ethernet 'eth0' { # doesn't matter - address '192.0.2.1/24' # significant! - disable # significant! - - # empty line -- doesn't matter - hw-id 00:aa:bb:cc:dd:ee # significant! - } # doesn't matter -} - -If there were explicit terminators (like we do in VyConf, or like JunOS does), -the language would be context free. Enter the lexer hack: let's emit newlines only -when they are significant, so that the parser can use them as terminators. - -The informal idea is that a newline is only significant if it follows a leaf node. -So we need rules for finding out if we are inside a leaf node or not. - -These are the formal rules. A newline is significant if and only if -1. Preceding token is an identifier -2. Preceding token is a quoted string - -We set the vy_inside_node flag to true when we enter a leaf node and reset it when -we reach the end of it. - -*) - -let vy_inside_node = ref false - -} - -rule token = parse -| [' ' '\t' '\r'] - { token lexbuf } -| '\n' - { Lexing.new_line lexbuf; if !vy_inside_node then (vy_inside_node := false; NEWLINE) else token lexbuf } -| '"' - { vy_inside_node := true; read_string (Buffer.create 16) lexbuf } -| ''' - { vy_inside_node := true; read_single_quoted_string (Buffer.create 16) lexbuf } -| "/*" - { vy_inside_node := false; read_comment (Buffer.create 16) lexbuf } -| '{' - { vy_inside_node := false; LEFT_BRACE } -| '}' - { vy_inside_node := false; RIGHT_BRACE } -| "//" [^ '\n']* - { token lexbuf } -| [^ ' ' '\t' '\n' '\r' '{' '}' '"' ''' ]+ as s - { vy_inside_node := true; IDENTIFIER s} -| eof - { EOF } -| _ -{ raise (Error (Printf.sprintf "At offset %d: unexpected character.\n" (Lexing.lexeme_start lexbuf))) } - -and read_string buf = - parse - | '"' { STRING (Buffer.contents buf) } - | '\\' '/' { Buffer.add_char buf '/'; read_string buf lexbuf } - | '\\' '\\' { Buffer.add_char buf '\\'; read_string buf lexbuf } - | '\\' 'b' { Buffer.add_char buf '\b'; read_string buf lexbuf } - | '\\' 'f' { Buffer.add_char buf '\012'; read_string buf lexbuf } - | '\\' 'n' { Buffer.add_char buf '\n'; read_string buf lexbuf } - | '\\' 'r' { Buffer.add_char buf '\r'; read_string buf lexbuf } - | '\\' 't' { Buffer.add_char buf '\t'; read_string buf lexbuf } - | '\\' '\'' { Buffer.add_char buf '\''; read_string buf lexbuf } - | '\\' '"' { Buffer.add_char buf '"'; read_string buf lexbuf } - | '\n' { Lexing.new_line lexbuf; Buffer.add_char buf '\n'; read_string buf lexbuf } - | [^ '"' '\\']+ - { Buffer.add_string buf (Lexing.lexeme lexbuf); - read_string buf lexbuf - } - | _ { raise (Error (Printf.sprintf "Illegal string character: %s" (Lexing.lexeme lexbuf))) } - | eof { raise (Error ("String is not terminated")) } - -and read_single_quoted_string buf = - parse - | ''' { STRING (Buffer.contents buf) } - | '\\' '/' { Buffer.add_char buf '/'; read_string buf lexbuf } - | '\\' '\\' { Buffer.add_char buf '\\'; read_string buf lexbuf } - | '\\' 'b' { Buffer.add_char buf '\b'; read_string buf lexbuf } - | '\\' 'f' { Buffer.add_char buf '\012'; read_string buf lexbuf } - | '\\' 'n' { Buffer.add_char buf '\n'; read_string buf lexbuf } - | '\\' 'r' { Buffer.add_char buf '\r'; read_string buf lexbuf } - | '\\' 't' { Buffer.add_char buf '\t'; read_string buf lexbuf } - | '\\' '\'' { Buffer.add_char buf '\''; read_string buf lexbuf } - | '\\' '"' { Buffer.add_char buf '"'; read_string buf lexbuf } - | '\n' { Lexing.new_line lexbuf; Buffer.add_char buf '\n'; read_string buf lexbuf } - | [^ ''' '\\']+ - { Buffer.add_string buf (Lexing.lexeme lexbuf); - read_single_quoted_string buf lexbuf - } - | _ { raise (Error (Printf.sprintf "Illegal string character: %s" (Lexing.lexeme lexbuf))) } - | eof { raise (Error ("String is not terminated")) } - -and read_comment buf = - parse - | "*/" - { COMMENT (Buffer.contents buf) } - | _ - { Buffer.add_string buf (Lexing.lexeme lexbuf); - read_comment buf lexbuf - } - -(* - -If you are curious how the original parsers handled the issue: they did not. -The CStore parser cheated by reading data from command definitions to resolve -the ambiguities, which made it impossible to use in standalone config -manipulation programs like migration scripts. - -The XorpConfigParser could not tell tag nodes' name and tag from -a leaf node with a value, which made it impossible to manipulate -tag nodes or change values properly. - -*) diff --git a/parser/vyos1x_parser.mly b/parser/vyos1x_parser.mly deleted file mode 100644 index 707538d..0000000 --- a/parser/vyos1x_parser.mly +++ /dev/null @@ -1,117 +0,0 @@ -%{ - open Config_tree - - exception Duplicate_child of (string * string) - - (* Used for checking if after merging immediate children, - any of them have duplicate children inside, - e.g. "interfaces { ethernet eth0 {...} ethernet eth0 {...} }" *) - let find_duplicate_children n = - let rec aux xs = - let xs = List.sort compare xs in - match xs with - | [] | [_] -> () - | x :: x' :: xs -> - if x = x' then raise (Duplicate_child (Vytree.name_of_node n, x)) - else aux (x' :: xs) - in - aux @@ Vytree.list_children n - - (* When merging nodes with values, append values of subsequent nodes to the - first one *) - let merge_data l r = {l with values=(List.append l.values r.values)} -%} - -%token <string> IDENTIFIER -%token <string> STRING -%token <string> COMMENT -%token LEFT_BRACE -%token RIGHT_BRACE -%token NEWLINE -%token EOF - -%start <Config_tree.t> config -%% - -(* If there are multiple comments before a node, consider the last one its real comment *) -comments: - cs = list(COMMENT) { match cs with [] -> None | _ -> Some (List.rev cs |> List.hd |> String.trim) } - -value: - | v = STRING - { v } - | v = IDENTIFIER - { v } -; - - -leaf_node_body: - | comment = comments; - name = IDENTIFIER; value = value; - { Vytree.make_full {default_data with values=[value]; comment=comment} name []} - | comment = comments; - name = IDENTIFIER; (* valueless node *) - { Vytree.make_full {default_data with comment=comment} name [] } -; - -leaf_node: - | n = leaf_node_body; NEWLINE; - { n } - | n = leaf_node_body; EOF; - { n } - -node: - | comment = comments; - name = IDENTIFIER; LEFT_BRACE; children = list(node_content); RIGHT_BRACE; - { - let node = - Vytree.make_full {default_data with comment=comment} name [] in - let node = List.fold_left Vytree.adopt node (List.rev children) |> Vytree.merge_children merge_data in - try - List.iter find_duplicate_children (Vytree.children_of_node node); - node - with - | Duplicate_child (child, dup) -> - failwith (Printf.sprintf "Node \"%s %s\" has two children named \"%s\"" name child dup) - } -; - -(* XXX: for the config to be loadable with the old CStore backend, what was formatted as a tag node - in the original config, must remain formatted that way. - Since fixing it there is more trouble than it's worth, and creating a separate version of - Config_tree just for that seems strange, I reused the ephemeral flag for that, which - is never used in the VyOS 1.x context anyway. - *) -tag_node: - | comment = comments; - name = IDENTIFIER; tag = value; LEFT_BRACE; children = list(node_content); RIGHT_BRACE - { - let outer_node = Vytree.make_full {default_data with ephemeral=true} name [] in - let inner_node = - Vytree.make_full {default_data with comment=comment} tag [] in - let inner_node = List.fold_left Vytree.adopt inner_node (List.rev children) |> Vytree.merge_children merge_data in - let node = Vytree.adopt outer_node inner_node in - try - List.iter find_duplicate_children (Vytree.children_of_node inner_node); - node - with - | Duplicate_child (child, dup) -> - failwith (Printf.sprintf "Node \"%s %s %s\" has two children named \"%s\"" name tag child dup) - } - -node_content: n = node { n } | n = leaf_node { n } | n = tag_node { n }; - - -%public config: - | ns = list(node_content); EOF - { - let root = make "root" in - let root = List.fold_left Vytree.adopt root (List.rev ns) |> Vytree.merge_children merge_data in - try - List.iter find_duplicate_children (Vytree.children_of_node root); - root - with - | Duplicate_child (child, dup) -> - failwith (Printf.sprintf "Node \"%s\" has two children named \"%s\"" child dup) - } -; 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