Fixed the entire feature

Author: Happypig375

src/FSharpPlus/Parsing.fs

@@ -11,7 +11,7 @@ module Parsing =
     open FSharpPlus.Internals
     open FSharpPlus.Internals.Prelude
 
-    let inline private getGroups (pf: PrintfFormat<_,_,_,_,_>) str =
+    let getGroups (pf: PrintfFormat<_,_,_,_,_>) str =
         let format = pf.Value
         let regex = System.Text.StringBuilder "^"
         let mutable groups = FSharp.Core.CompilerServices.ArrayCollector()
@@ -33,7 +33,7 @@ module Parsing =
                 | 'B' -> "([01]+)"
                 | 'c' -> "(.)"
                 | 'd' | 'i' -> "([+-]?[0-9]+)"
-                | 'e' | 'E' | 'f' | 'F' | 'g' | 'G' | 'M' -> "([+-]?(?:[0-9]+(?:\.[0-9]*)?|\.[0-9]+)(?:[eE][+-]?[0-9]+)?)"
+                | 'e' | 'E' | 'f' | 'F' | 'g' | 'G' | 'M' -> "([+-]?[0-9.]+(?:[eE][+-]?[0-9]+)?)"
                 | 'o' -> "([0-7]+)"
                 | 'u' -> "([0-9]+)"
                 | 's' -> "(.*?)"
@@ -50,12 +50,14 @@ module Parsing =
         |> string
         |> Regex
         |> _.Match(str)
-        |> _.Groups
+        |> fun m ->
+        if not m.Success then [||] else
+        m.Groups
         |> Seq.cast<Group>
         |> Seq.skip 1
         |> Seq.map _.Value
         |> Seq.toArray 
-        |> Array.zip <| groups.Close()      
+        |> Array.zip <| groups.Close()
 
     let inline private conv (destType: System.Type) (b: int) (s: string) =
         match destType with    

tests/FSharpPlus.Tests/Parsing.fs

@@ -100,17 +100,24 @@ module Parsing =
 
 
         let _zzz = sscanf "(%%%s)" "(%hello)"
+        let _zzz1 = sscanf "%%(%s)" "%(hello)"
         let (_x1,_y1,_z1) = sscanf "%s--%s-%s" "test--this-string"
 
         let inline (|Like|_|) format = FSharpPlus.Parsing.trySscanf format
-        match "(%hello)" with Like "(%%%s)" "hello" -> () | _ -> failwith "didn't match"
+        match "ab" with Like "%c" _ -> failwith "wrong match" | Like "%c%c" ('a', 'b') -> () | _ -> failwith "didn't match"
+        match "abc" with Like "%c%c" ('a', 'b') -> failwith "wrong match" | Like "%c%c%c%s" ('a', 'b', 'c', "") -> () | _ -> failwith "didn't match"
+        match "(%hello)" with
+        | Like "%d" _ | Like "%f" _ | Like "%x" _ -> failwith "wrong match"
+        | Like "%%(%%%s)" _ | Like "(%%%sa" _ | Like "(%%hel%c" _ | Like "%%h%cllo)" _ -> failwith "wrong match"
+        | Like "(%%%s)" "hello" -> ()
+        | _ -> failwith "didn't match"
         match "test--this-gg" with Like "%s--%s-%s" ("test", "this", "gg") -> () | _ -> failwith "didn't match"
         match "1 2.1 3.4 .3 43.2e32 0 f f" with Like "%f %F %g %G %e %E %c %c" (1f, 2.1, 3.4, 0.3, 43.2e32, 0., 'f', 'f') -> () | _ -> failwith "didn't match"
         match "1 2.1 3.4 .3 43.2e32 0 f f f" with Like "%f %F %g %G %e %E %c %c %c" (1f, 2.1, 3.4, 0.3, 43.2e32, 0., 'f', 'f', 'f') -> () | _ -> failwith "didn't match"
-        match "1 2.1 3.4 .3 43.2e32 0 f f ff" with Like "%f %F %g %G %e %E %c %c %c%c" (1f, 2.1, 3.4, 0.3, 43.2e32, 0., 'f', 'f', 'f', 'f') -> () | _ -> failwith "didn't match"
-        match "1 2.1 3.4 .3 43.2e32 0 f f fff" with Like "%f %F %g %G %e %E %c %c %c%c%c" (1f, 2.1, 3.4, 0.3, 43.2e32, 0., 'f', 'f', 'f', 'f', 'f') -> () | _ -> failwith "didn't match"
-        match "1 2.1 3.4 .3 43.2e32 0 f f fff 16" with Like "%f %F %g %G %e %E %c %c %c%c%c%i" (1f, 2.1, 3.4, 0.3, 43.2e32, 0., 'f', 'f', 'f', 'f', 'f', 16) -> () | _ -> failwith "didn't match"
-        match "1 2.1 3.4 .3 43.2e32 0 f f fff 16 17" with Like "%f %F %g %G %e %E %c %c %c%c%c%i %f" (1f, 2.1, 3.4, 0.3, 43.2e32, 0., 'f', 'f', 'f', 'f', 'f', 16, 17.) -> () | _ -> failwith "didn't match"
+        match "1 2.1 3.4 .3 43.2e32 0 f f ff" with Like "%B %F %g %G %e %E %c %c %c%c" (1, 2.1, 3.4, 0.3, 43.2e32, 0., 'f', 'f', 'f', 'f') -> () | _ -> failwith "didn't match"
+        match "1 2.1 3.4 .3 43.2e32 0 f f fff" with Like "%o %F %g %G %e %E %c %c %c%c%c" (1, 2.1, 3.4, 0.3, 43.2e32, 0., 'f', 'f', 'f', 'f', 'f') -> () | _ -> failwith "didn't match"
+        match "1 2.1 3.4 .3 43.2e32 0 f f fff16" with Like "%x %F %g %G %e %E %c %c %c%c%c%i" (1, 2.1, 3.4, 0.3, 43.2e32, 0., 'f', 'f', 'f', 'f', 'f', 16) -> () | _ -> failwith "didn't match"
+        match "1 2.1 3.4 .3 43.2e32 0 f f fff16 17" with Like "%X %F %g %G %e %E %c %c %c%c%c%i %f" (1, 2.1, 3.4, 0.3, 43.2e32, 0., 'f', 'f', 'f', 'f', 'f', 16, 17.) -> () | _ -> failwith "didn't match"
         match "13 43 AA 77A" with Like "%x %X %x %o%X" (0x13, 0x43, 0xAA, 0o77, 0xA) -> () | _ -> failwith "didn't match"
         match "13 43 AA 77A" with Like "%B%x %X %x %o%X" (0b1, 0x3, 0x43, 0xAA, 0o77, 0xA) -> () | _ -> failwith "didn't match"
         match "111AAA" with Like "%B%s" (0b111, "AAA") -> () | _ -> failwith "didn't match"