Add .fsi example

examples/fsharp_signature_files/BUILD.bazel

@@ -0,0 +1,16 @@
+load(
+    "@rules_dotnet//dotnet:defs.bzl",
+    "fsharp_library",
+)
+
+fsharp_library(
+    name = "fsharp_signature_files",
+    srcs = [
+        "domain.fsi",
+        "domain.fs",
+    ],
+    target_frameworks = ["netstandard2.1"],
+    deps = [
+        "@paket.example_deps//fsharp.core",
+    ],
+)

examples/fsharp_signature_files/domain.fs

@@ -0,0 +1,22 @@
+namespace Domain
+
+type OrderID =
+  | OrderID of string
+
+[<RequireQualifiedAccess>]
+module OrderID =
+
+  open System
+  open System.Text.RegularExpressions
+
+  let pattern = Regex "^[a-z][a-z0-9]{5}$"
+
+  let tryParse (x : string) : OrderID option =
+    if pattern.IsMatch(x) then
+      Some (OrderID x)
+    else
+      None
+
+  let toString (x : OrderID) : string =
+    let (OrderID s) = x
+    s

examples/fsharp_signature_files/domain.fsi

@@ -0,0 +1,8 @@
+namespace Domain
+
+type OrderID = internal | OrderID of string
+
+[<RequireQualifiedAccess>]
+module OrderID =
+  val tryParse : string -> OrderID option
+  val toString : OrderID -> string

examples/fsharp_signature_files/fsharp_signature_files.fsproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>netstandard2.1</TargetFramework>
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="domain.fsi" />
+    <Compile Include="domain.fs" />
+  </ItemGroup>
+</Project>