Extract some utilities from http-client branch (#260)

WoofWare.Myriad.Plugins/SynExpr/Ident.fs

@@ -2,6 +2,7 @@ namespace WoofWare.Myriad.Plugins
 
 open System
 open System.Text
+open System.Text.RegularExpressions
 open Fantomas.FCS.Syntax
 open Fantomas.FCS.Text.Range
 
@@ -9,6 +10,53 @@ open Fantomas.FCS.Text.Range
 module internal Ident =
     let inline create (s : string) = Ident (s, range0)
 
+    /// Fantomas bug, perhaps? "type" is not rendered as ``type``, although the ASTs are identical
+    /// apart from the ranges?
+    /// Awful hack: here is a function that does this sort of thing.
+    let createSanitisedParamName (s : string) =
+        match s with
+        | "type" -> create "type'"
+        | _ ->
+
+        let result = StringBuilder ()
+
+        for i = 0 to s.Length - 1 do
+            if Char.IsLetter s.[i] then
+                result.Append s.[i] |> ignore<StringBuilder>
+            elif Char.IsNumber s.[i] then
+                if result.Length > 0 then
+                    result.Append s.[i] |> ignore<StringBuilder>
+            elif s.[i] = '_' || s.[i] = '-' then
+                result.Append '_' |> ignore<StringBuilder>
+            else
+                failwith $"could not convert to ident: %s{s}"
+
+        create (result.ToString ())
+
+    let private alnum = Regex @"^[a-zA-Z][a-zA-Z0-9]*$"
+
+    let createSanitisedTypeName (s : string) =
+        let result = StringBuilder ()
+        let mutable capitalize = true
+
+        for i = 0 to s.Length - 1 do
+            if Char.IsLetter s.[i] then
+                if capitalize then
+                    result.Append (Char.ToUpperInvariant s.[i]) |> ignore<StringBuilder>
+                    capitalize <- false
+                else
+                    result.Append s.[i] |> ignore<StringBuilder>
+            elif Char.IsNumber s.[i] then
+                if result.Length > 0 then
+                    result.Append s.[i] |> ignore<StringBuilder>
+            elif s.[i] = '_' then
+                capitalize <- true
+
+        if result.Length = 0 then
+            failwith $"String %s{s} was not suitable as a type identifier"
+
+        Ident (result.ToString (), range0)
+
     let lowerFirstLetter (x : Ident) : Ident =
         let result = StringBuilder x.idText.Length
         result.Append (Char.ToLowerInvariant x.idText.[0]) |> ignore