Iceshrimp.NET/Iceshrimp.Parsing/Mfm.fs
2024-06-17 01:19:20 +02:00

337 lines
11 KiB
FSharp

namespace Iceshrimp.Parsing
open System
open System.Collections.Generic
open System.Runtime.Serialization
open FParsec
module MfmNodeTypes =
[<AbstractClass>]
type MfmNode() =
member val Children: MfmNode list = [] with get, set
[<AbstractClass>]
type MfmInlineNode(c: MfmInlineNode list) =
inherit MfmNode()
do base.Children <- c |> List.map (fun x -> x :> MfmNode)
[<AbstractClass>]
type MfmBlockNode(c: MfmInlineNode list) =
inherit MfmNode()
do base.Children <- c |> List.map (fun x -> x :> MfmNode)
type MfmTextNode(v: string) =
inherit MfmInlineNode([])
member val Text = v
type MfmItalicNode(c) =
inherit MfmInlineNode(c)
type MfmBoldNode(c) =
inherit MfmInlineNode(c)
type MfmStrikeNode(c) =
inherit MfmInlineNode(c)
type MfmInlineCodeNode(v: string) =
inherit MfmInlineNode([])
member val Code = v
type MfmPlainNode(v: string) =
inherit MfmInlineNode([ MfmTextNode(v) ])
type MfmSmallNode(c) =
inherit MfmInlineNode(c)
type MfmQuoteNode(c) =
inherit MfmBlockNode(c)
type MfmSearchNode(content: string, query: string) =
inherit MfmBlockNode([])
member val Content = content
member val Query = query
type MfmCodeBlockNode(code, lang: string option) =
inherit MfmBlockNode([])
member val Code = code
member val Language = lang
type MfmMathBlockNode(f) =
inherit MfmBlockNode([])
member val Formula = f
type MfmCenterNode(c) =
inherit MfmBlockNode(c)
type MfmEmojiCodeNode(n) =
inherit MfmInlineNode([])
member val Name = n
type MfmMathInlineNode(f) =
inherit MfmInlineNode([])
member val Formula = f
type MfmMentionNode(acct, user, host: string option) =
inherit MfmInlineNode([])
member val Acct = acct
member val Username = user
member val Host = host
type MfmHashtagNode(h) =
inherit MfmInlineNode([])
member val Hashtag = h
type MfmUrlNode(url, brackets) =
inherit MfmInlineNode([])
member val Url = url
member val Brackets = brackets
type MfmLinkNode(url, text, silent) =
inherit MfmInlineNode([ MfmTextNode(text) ])
member val Url = url
member val Silent = silent
type MfmFnNode(args: Dictionary<string, string>, name, children) =
inherit MfmInlineNode(children)
// (string, bool) args = (string, null as string?)
member val Args = args
member val Name = name
type internal MfmCharNode(v: char) =
inherit MfmInlineNode([])
member val Char = v
open MfmNodeTypes
module private MfmParser =
// Abstractions
let str s = pstring s
let seqAttempt s = s |> Seq.map attempt
let isWhitespace c = Char.IsWhiteSpace c
let isNotWhitespace c = Char.IsWhiteSpace c = false
let isAsciiLetterOrNumber c = Char.IsAsciiLetter c || Char.IsDigit c
let isLetterOrNumber c = Char.IsLetterOrDigit c
let (|CharNode|MfmNode|) (x: MfmNode) =
if x :? MfmCharNode then
CharNode(x :?> MfmCharNode)
else
MfmNode x
let folder (current, result) node =
match (node: MfmNode), (current: char list) with
| CharNode node, _ -> node.Char :: current, result
| MfmNode node, [] -> current, node :: result
| MfmNode node, _ -> [], node :: (MfmTextNode(current |> List.toArray |> String) :: result)
let aggregateText nodes =
nodes
|> List.rev
|> List.fold folder ([], [])
|> function
| [], result -> result
| current, result -> MfmTextNode(current |> List.toArray |> String) :: result
let aggregateTextInline nodes =
nodes |> aggregateText |> List.map (fun x -> x :?> MfmInlineNode)
let domainComponent =
many1Chars (
satisfy isAsciiLetterOrNumber
<|> pchar '_'
<|> attempt (
previousCharSatisfies isAsciiLetterOrNumber >>. pchar '-'
.>> lookAhead (satisfy isAsciiLetterOrNumber)
)
<|> attempt (
(previousCharSatisfies '-'.Equals <|> previousCharSatisfies isAsciiLetterOrNumber)
>>. pchar '-'
.>> lookAhead (satisfy '-'.Equals <|> satisfy isAsciiLetterOrNumber)
)
)
let domain =
domainComponent .>>. (many <| attempt (skipChar '.' >>. domainComponent))
|>> fun (a, b) -> String.concat "." <| Seq.append [ a ] b
let acct (user: string, host: string option) =
match host with
| None -> user
| Some v -> user + "@" + v
// References
let node, nodeRef = createParserForwardedToRef ()
let inlineNode, inlineNodeRef = createParserForwardedToRef ()
let seqFlatten items =
seq {
for item in items do
yield! item
}
// Patterns
let italicPattern = (notFollowedBy <| str "**") >>. skipChar '*'
let codePattern = (notFollowedBy <| str "```") >>. skipChar '`'
// Matchers
let hashtagMatcher = letter <|> digit <|> anyOf "-_"
let hashtagSatisfier = attempt hashtagMatcher
// Node parsers
let italicNode =
italicPattern >>. manyTill inlineNode italicPattern
|>> fun c -> MfmItalicNode(aggregateTextInline c) :> MfmNode
//TODO: https://github.com/pzp1997/harkdown/blob/master/src/InlineParser.hs#L173-L201
let boldNode =
skipString "**" >>. manyTill inlineNode (skipString "**")
|>> fun c -> MfmBoldNode(aggregateTextInline c) :> MfmNode
let strikeNode =
skipString "~~" >>. manyTill inlineNode (skipString "~~")
|>> fun c -> MfmStrikeNode(aggregateTextInline c) :> MfmNode
let codeNode =
codePattern >>. manyCharsTill anyChar codePattern
|>> fun v -> MfmInlineCodeNode(v) :> MfmNode
let codeBlockNode =
previousCharSatisfiesNot isNotWhitespace
>>. skipString "```"
>>. opt (many1CharsTill asciiLetter (lookAhead newline))
.>>. (skipNewline
>>. manyCharsTill anyChar (attempt (skipNewline >>. skipString "```")))
|>> fun (lang: string option, code: string) -> MfmCodeBlockNode(code, lang) :> MfmNode
let mathNode =
skipString "\(" >>. manyCharsTill anyChar (skipString "\)")
|>> fun f -> MfmMathInlineNode(f) :> MfmNode
let mathBlockNode =
previousCharSatisfiesNot isNotWhitespace
>>. skipString "\["
>>. many1CharsTill anyChar (skipString "\]")
|>> fun f -> MfmMathBlockNode(f) :> MfmNode
let emojiCodeNode =
skipChar ':'
>>. manyCharsTill (satisfy isAsciiLetter <|> satisfy isDigit <|> anyOf "+-_") (skipChar ':')
|>> fun e -> MfmEmojiCodeNode(e) :> MfmNode
let plainNode =
skipString "<plain>" >>. manyCharsTill anyChar (skipString "</plain>")
|>> fun v -> MfmPlainNode(v) :> MfmNode
let smallNode =
skipString "<small>" >>. manyTill inlineNode (skipString "</small>")
|>> fun c -> MfmSmallNode(aggregateTextInline c) :> MfmNode
let centerNode =
skipString "<center>" >>. manyTill inlineNode (skipString "</center>")
|>> fun c -> MfmCenterNode(aggregateTextInline c) :> MfmNode
let mentionNode =
previousCharSatisfiesNot isNotWhitespace
>>. skipString "@"
>>. many1Chars (
satisfy isLetterOrNumber
<|> pchar '_'
<|> attempt (anyOf ".-" .>> nextCharSatisfies isLetterOrNumber)
)
.>>. opt (skipChar '@' >>. domain)
.>> (lookAhead
<| choice
[ eof
skipNoneOf ":"
skipChar ':' .>> nextCharSatisfiesNot isAsciiLetterOrNumber ])
|>> fun (user: string, host: string option) -> MfmMentionNode(acct (user, host), user, host) :> MfmNode
let hashtagNode =
previousCharSatisfiesNot isNotWhitespace
>>. skipChar '#'
>>. many1CharsTill hashtagMatcher (notFollowedBy hashtagSatisfier)
|>> fun h -> MfmHashtagNode(h) :> MfmNode
let urlNodePlain =
lookAhead (skipString "https://" <|> skipString "http://")
>>. manyCharsTill anyChar (nextCharSatisfies isWhitespace <|> nextCharSatisfies (isAnyOf "()") <|> eof) //FIXME: this needs significant improvements
>>= fun uri ->
match Uri.TryCreate(uri, UriKind.Absolute) with
| true, finalUri ->
match finalUri.Scheme with
| "http" -> preturn (MfmUrlNode(uri, false) :> MfmNode)
| "https" -> preturn (MfmUrlNode(uri, false) :> MfmNode)
| _ -> fail "invalid scheme"
| _ -> fail "invalid url"
let urlNodeBrackets =
skipChar '<'
>>. lookAhead (skipString "https://" <|> skipString "http://")
>>. manyCharsTill anyChar (skipChar '>')
>>= fun uri ->
match Uri.TryCreate(uri, UriKind.Absolute) with
| true, finalUri ->
match finalUri.Scheme with
| "http" -> preturn (MfmUrlNode(uri, true) :> MfmNode)
| "https" -> preturn (MfmUrlNode(uri, true) :> MfmNode)
| _ -> fail "invalid scheme"
| _ -> fail "invalid url"
let urlNode = urlNodePlain <|> urlNodeBrackets
let linkNode =
(opt (pchar '?'))
.>>. (pchar '[' >>. manyCharsTill anyChar (pchar ']'))
.>>. (pchar '('
>>. lookAhead (skipString "https://" <|> skipString "http://")
>>. manyCharsTill anyChar (pchar ')'))
>>= fun ((silent, text), uri) ->
match Uri.TryCreate(uri, UriKind.Absolute) with
| true, finalUri ->
match finalUri.Scheme with
| "http" -> preturn (MfmLinkNode(uri, text, silent.IsSome) :> MfmNode)
| "https" -> preturn (MfmLinkNode(uri, text, silent.IsSome) :> MfmNode)
| _ -> fail "invalid scheme"
| _ -> fail "invalid url"
let charNode = anyChar |>> fun v -> MfmCharNode(v) :> MfmNode
// Node collection
let inlineNodeSeq =
[ italicNode
boldNode
strikeNode
hashtagNode
mentionNode
codeNode
urlNode
linkNode
mathNode
emojiCodeNode
charNode ]
//TODO: still missing: FnNode, MfmSearchNode, MfmQuoteNode
let blockNodeSeq =
[ plainNode; centerNode; smallNode; codeBlockNode; mathBlockNode ]
let nodeSeq = [ blockNodeSeq; inlineNodeSeq ]
// Populate references
do nodeRef.Value <- choice <| seqAttempt (seqFlatten <| nodeSeq)
do inlineNodeRef.Value <- choice <| (seqAttempt inlineNodeSeq) |>> fun v -> v :?> MfmInlineNode
// Final parse command
let parse = spaces >>. manyTill node eof .>> spaces
open MfmParser
module Mfm =
let parse str =
match run parse str with
| Success(result, _, _) -> aggregateText result
| Failure(s, _, _) -> failwith $"Failed to parse MFM: {s}"