rfc2822解析多个标头行

Question

我试图使用fparsec解析RFC 2822，但是我无法处理多行标题：(它会与下一个标题混淆)：下面是我的最佳尝试:您有任何提示吗？

let str (s:string) = pstring s

let stringLiteral =
    manySatisfy (fun c -> c <> ':' && c <> '\r' && c <> '\n')

let ws = many (pchar ' ')

let keyValueSimple  =  stringLiteral .>>. (ws >>. str ":" >>. ws >>. stringLiteral) .>>. pchar '\n' |>> (fun (a,b) -> a)

let lineValue = ws >>. stringLiteral .>>. (pchar '\n' .>>. ( pchar '\t')) |>> ( fun (a,b) -> a )

let lastValue = ws >>. stringLiteral .>>. (pchar '\n' .>> notFollowedBy ( pchar '\t') ) |>> ( fun (a,b) -> a )

let keyValueComplex =  stringLiteral .>>. (ws >>. pchar ':') .>>. (many lineValue) .>>. lastValue |>> ( fun (((f),d),b) -> (f,f) )                     

let headers = many1 (keyValueComplex)

let parse (fileName:string) = 
    test headers "Return-Path: <ewrwe@werw.com>\n\twerwe\nDelivered-To: adfasdf@aasdfas.afa.com\n "

我期待3,1:交付到: adfasdf@aasdfas.afa.com

Answer 1

没关系，看起来我需要回溯(使用尝试)，以便解析器不总是期望一个\t，而是寻找下一个标头。

设keyValueComplex = stringLiteral .>>.(ws >>. )pchar ':') .>>.(许多(尝试lineValue)) .>>。lastValue |>> (g，h))，d)，b) -> (g，(Seq.fold (+)“d) + b) )

这现在产生了：

成功：(“返回路径”，"werwe")；(“交付-到”，"adfasdf@aasdfas.afa.com")