XParsec works with any type, is very easy to extend, supports domain-specific non-linear navigation and is implemented in a single F# file with just ~100 source lines of code.
(FParsec only works with
Chars and can only go forward on a one dimensional
XParsec.Xml is the first XParsec extension. It is implemented in just 14 source lines of code for the examples used below and provides complete freedom in navigating XML trees.
open XParsec open XParsec.Xml [<EntryPoint>] let main _ = let test parse = printfn "%A" << reply << parse << E.source let root = E.Parse "<root><a><b><c><d font='Arial'></d></c></b></a></root>" // domain-specific // navigation // v let parser1 = many (child => name) .>. !@"font" // ^ ^ // powerful first-class // combinators extensibility // graceful choices let parser2 = (parent => name) </> (!*child >. !@"font") // graceful non-linear look-ahead (here = down in Xml) let parser3 = !!parser1 .>. (current => name) // brand-new non-linear look-back (here = up in Xml) let S d,_ = E.source root |> (!*child >. current) let parser4 = !!(many (parent => name)) .>. (current => name) test parser1 root; test parser2 root; test parser3 root; test parser4 d; 0
S (["a"; "b"; "c"; "d"], "Arial") S "Arial" S ((["a"; "b"; "c"; "d"], "Arial"), "root") S (["c"; "b"; "a"; "root"], "d")
Recursion – handled with ease.
open XParsec open XParsec.Xml type Xobj = I of int | L of Xobj list [<EntryPoint>] let main _ = let root = E.Parse "<list><int v='1'/><list><int v='2'/></list><int v='3'/></list>" let e,e' = future () let int_ = !<>"int" >. !@"v" => (Int32.Parse >> I) let list = !<>"list" >. children e => L do e' := int_ </> list test e root; 0
S (L [I 1; L [I 2]; I 3])
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