Fast api

.editorconfig

@@ -4,3 +4,4 @@ root = true
 fsharp_multiline_bracket_style = stroustrup
 fsharp_record_multiline_formatter = number_of_items
 fsharp_max_record_number_of_items = 1
+fsharp_max_infix_operator_expression = 60

.vscode/settings.json

@@ -2,6 +2,7 @@
     "cSpell.words": [
         "aiohttp",
         "alfonsogarciacaro",
+        "boto",
         "Buildalyzer",
         "coro",
         "destructures",
@@ -19,9 +20,13 @@
         "nativeint",
         "ncave",
         "pathlib",
+        "pdfplumber",
+        "Plotly",
         "pyfile",
         "pyname",
+        "Pythonistas",
         "Pyxpecto",
+        "scikit",
         "Sergey",
         "stroustrup",
         "Tihon",

CLAUDE.md

@@ -95,4 +95,4 @@ docs/
 
 - [Fable.Python docs](https://fable.io/docs/getting-started/python.html)
 - [Fable.Python GitHub](https://github.com/fable-compiler/Fable.Python/)
-- [Content Plan](CONTENT-PLAN.md) - Chapter structure and TODO items
+- [Content Plan](CONTENT-PLAN.md) - Chapter structure and TODO items (important!)

Fable.Literate/App.fs

@@ -100,7 +100,9 @@ module Utils =
                     if m.Value.Length = 1 then
                         m.Value.ToLowerInvariant()
                     else
-                        m.Value.Substring(0, 1) + "_" + m.Value.Substring(1, 1).ToLowerInvariant()
+                        m.Value.Substring(0, 1)
+                        + "_"
+                        + m.Value.Substring(1, 1).ToLowerInvariant()
             )
         else
             name
@@ -328,7 +330,10 @@ module MarkdownPrinter =
         | IncludePython symbols ->
             // Unresolved - should have been transformed
             let symbolList = String.concat ", " symbols
-            "\n<!-- include-python: " + symbolList + " (unresolved) -->\n"
+
+            "\n<!-- include-python: "
+            + symbolList
+            + " (unresolved) -->\n"
         | Hidden _ -> "" // Should have been filtered
 
     /// Render a document to markdown string.
@@ -348,7 +353,11 @@ module MarkdownPrinter =
             | s when s.StartsWith "#" -> inCodeBlock, ("#" + line) :: acc
             | _ -> inCodeBlock, line :: acc
 
-        lines |> Array.fold folder (false, []) |> snd |> List.rev |> String.concat "\n"
+        lines
+        |> Array.fold folder (false, [])
+        |> snd
+        |> List.rev
+        |> String.concat "\n"
 
 (**
 ## Pipeline Module

Fable.Literate/Fable.Literate.fsproj

@@ -8,7 +8,7 @@
 
   <ItemGroup>
     <PackageReference Include="Fable.Core" Version="5.0.0-beta.4" />
-    <PackageReference Include="Fable.Python" Version="5.0.0-alpha.21.0" />
+    <PackageReference Include="Fable.Python" Version="5.0.0-alpha.21.5" />
   </ItemGroup>
 
   <ItemGroup>

README.md

@@ -2,7 +2,7 @@
 
 > Write F#, run Python - a practical guide to Fable.Python
 
-This is a comprehensive guide to [Fable.Python](https://github.com/fable-compiler/Fable.Python/), written as literate F# that transpiles to Python and generates its own documentation.
+This blog-post is a guide to [Fable.Python](https://github.com/fable-compiler/Fable.Python/), written as literate F# that transpiles to Python and generates its own documentation.
 
 ## Chapters
 
@@ -23,9 +23,10 @@ This is a comprehensive guide to [Fable.Python](https://github.com/fable-compile
 
 ## The Strange Loop
 
-This guide is self-documenting: each chapter is an `.fs` file with embedded Markdown comments. **Fabletext** (the final chapter) processes these files to generate the documentation you're reading - including itself.
+This guide is self-documenting: each chapter is an `.fs` file with embedded Markdown comments. **Fable.Literate** (the final chapter) processes these files to generate the documentation you're reading - including itself.
 
 The chain:
+
 1. Write F# with embedded Markdown (`chapters/*.fs`)
 2. Compile to Python with Fable
 3. Run Fabletext (F# compiled to Python) to extract documentation

chapters/AsyncProgramming.fs

@@ -76,7 +76,9 @@ F# async shines when composing multiple operations:
 
 let fetchMultipleAsync () =
     async {
-        let! results = [ fetchDataAsync (); fetchDataAsync (); fetchDataAsync () ] |> Async.Parallel
+        let! results =
+            [ fetchDataAsync (); fetchDataAsync (); fetchDataAsync () ]
+            |> Async.Parallel
 
         return results |> Array.toList
     }
@@ -398,7 +400,9 @@ When you need rich composition primitives:
 let complexWorkflow () =
     async {
         // Run three operations in parallel
-        let! results = [ fetchDataAsync (); fetchDataAsync (); fetchDataAsync () ] |> Async.Parallel
+        let! results =
+            [ fetchDataAsync (); fetchDataAsync (); fetchDataAsync () ]
+            |> Async.Parallel
 
         // Then do something sequential
         do! Async.Sleep 100

chapters/Bindings.fs

@@ -3,9 +3,13 @@ module Bindings
 (**
 # Creating Python Bindings
 
-When a Python library doesn't have F# bindings, you can create your own.
-This chapter covers the patterns and best practices for writing type-safe
-bindings that feel natural in F#.
+When a Python library doesn't have F# bindings, you can create your own. This chapter
+covers the patterns and best practices for writing type-safe bindings that feel natural
+in F#.
+
+> Writing bindings have long been a major pain point, spending countless hours wrestling
+> with interop details. With AI-assisted coding tools, generating initial binding code
+> for your favorite Python libraries has become much easier.
 
 ## Core Principles
 
@@ -273,6 +277,5 @@ let createClient url = myLibrary.createClient url
 
 ## What's Next?
 
-Now you know how to create bindings. The **Compatibility** chapter covers
-which F# features work with Fable.Python and any limitations to be aware of.
+With bindings covered, the **Compatibility** chapter shows which F# features work with Fable.Python and any limitations to be aware of.
 *)

chapters/FastAPI.fs

@@ -97,27 +97,35 @@ let items = ResizeArray<Item>()
 type API() =
     /// GET /items - List all items
     [<Get("/items")>]
-    static member get_items() : ResizeArray<Item> =
-        items
+    static member get_items() : ResizeArray<Item> = items
 
     /// GET /items/{item_id} - Get item by ID
     [<Get("/items/{item_id}")>]
-    static member get_item(item_id: int) : Task<obj> = task {
-        match items |> Seq.tryFind (fun i -> i.Id = item_id) with
-        | Some item -> return item :> obj
-        | None -> return {| error = "Item not found" |}
-    }
+    static member get_item(item_id: int) : Task<obj> =
+        task {
+            match items |> Seq.tryFind (fun i -> i.Id = item_id) with
+            | Some item -> return item :> obj
+            | None -> return {| error = "Item not found" |}
+        }
 
     /// POST /items - Create a new item
     [<Post("/items")>]
-    static member create_item(request: CreateItemRequest) : Task<obj> = task {
-        let newId =
-            if items.Count = 0 then 1
-            else (items |> Seq.map (fun i -> i.Id) |> Seq.max) + 1
-        let newItem = Item(newId, request.Name, request.Price, request.InStock)
-        items.Add(newItem)
-        return {| status = "created"; item = newItem |}
-    }
+    static member create_item(request: CreateItemRequest) : Task<obj> =
+        task {
+            let newId =
+                if items.Count = 0 then
+                    1
+                else
+                    (items |> Seq.map (fun i -> i.Id) |> Seq.max) + 1
+
+            let newItem = Item(newId, request.Name, request.Price, request.InStock)
+            items.Add(newItem)
+
+            return {|
+                status = "created"
+                item = newItem
+            |}
+        }
 
 (**
 This generates Python with proper FastAPI decorators:
@@ -143,8 +151,10 @@ F# anonymous records compile to Python dictionaries, perfect for JSON responses:
 [<APIClass>]
 type HealthAPI() =
     [<Get("/health")>]
-    static member health() =
-        {| status = "healthy"; version = "1.0.0" |}
+    static member health() = {|
+        status = "healthy"
+        version = "1.0.0"
+    |}
 
 (**
 ## Async Endpoints
@@ -155,11 +165,12 @@ For I/O-bound operations, use `task { }` to create async endpoints:
 [<APIClass>]
 type AsyncAPI() =
     [<Get("/slow")>]
-    static member slow_operation() = task {
-        // Simulate async work (e.g., database query)
-        do! Task.Delay(100)
-        return {| message = "Done!" |}
-    }
+    static member slow_operation() =
+        task {
+            // Simulate async work (e.g., database query)
+            do! Task.Delay(100)
+            return {| message = "Done!" |}
+        }
 
 (**
 The `task { }` computation expression compiles to Python's `async def`,
@@ -175,12 +186,16 @@ Path parameters are extracted from the URL:
 [<APIClass>]
 type UsersAPI() =
     [<Get("/users/{user_id}")>]
-    static member get_user(user_id: int) =
-        {| id = user_id; name = "User " + string user_id |}
+    static member get_user(user_id: int) = {|
+        id = user_id
+        name = "User " + string user_id
+    |}
 
     [<Get("/users/{user_id}/posts/{post_id}")>]
-    static member get_user_post(user_id: int, post_id: int) =
-        {| user_id = user_id; post_id = post_id |}
+    static member get_user_post(user_id: int, post_id: int) = {|
+        user_id = user_id
+        post_id = post_id
+    |}
 
 (**
 ### Query Parameters
@@ -191,8 +206,10 @@ Query parameters are function arguments not in the path:
 [<APIClass>]
 type SearchAPI() =
     [<Get("/search")>]
-    static member search(q: string, limit: int) =
-        {| query = q; limit = limit |}
+    static member search(q: string, limit: int) = {|
+        query = q
+        limit = limit
+    |}
 
 (**
 A request to `/search?q=hello&limit=10` maps to `search("hello", 10)`.
@@ -213,7 +230,11 @@ type UserCrudAPI() =
     [<Post("/users")>]
     static member create_user(request: CreateUserRequest) =
         // FastAPI automatically validates the request body
-        {| status = "created"; name = request.name; email = request.email |}
+        {|
+            status = "created"
+            name = request.name
+            email = request.email
+        |}
 
 (**
 FastAPI validates the incoming JSON against the Pydantic model and returns
@@ -230,8 +251,10 @@ type ErrorAPI() =
     static member protected_route() =
         // Check authentication (simplified example)
         let isAuthenticated = false
+
         if not isAuthenticated then
             raise (System.Exception("Not authenticated"))
+
         {| message = "Secret data" |}
 
 (**
@@ -336,4 +359,51 @@ This combination gives you:
 4. **Familiar ecosystem** - Deploy with standard Python tools
 
 You write type-safe F# code, but deploy and run it like any Python web service.
+
+## Hybrid Architecture: F# Backend with Python Endpoints
+
+Another compelling use case is when you have an existing web service written in F# (using
+ASP.NET Core, Giraffe, or Oxpecker) but need access to the Python ecosystem for specific
+functionality. You can use FastAPI to expose endpoints that leverage Python libraries,
+while your main service remains in F#.
+
+This hybrid approach works well when you need:
+
+### AI/ML Libraries
+
+- **LangChain** / **LlamaIndex** - LLM orchestration and RAG pipelines
+- **Hugging Face Transformers** - Pre-trained models for NLP, vision, audio
+- **OpenAI SDK** / **Anthropic SDK** - LLM API integration with structured outputs
+- **scikit-learn** - Classical machine learning models
+- **PyTorch** / **TensorFlow** - Deep learning inference
+
+### Data Science & Analytics
+
+- **Pandas** / **Polars** - Data manipulation and analysis
+- **NumPy** - Numerical computing
+- **Matplotlib** / **Plotly** - Chart and visualization generation
+- **Apache Arrow** - Efficient cross-language data interchange
+
+### Document Processing
+
+- **PyMuPDF** / **pdfplumber** - PDF text and table extraction
+- **python-docx** - Word document generation
+- **Pillow** - Image processing and manipulation
+- **OpenCV** - Computer vision operations
+
+### Specialized APIs
+
+- **boto3** - AWS services (S3, Lambda, SQS, etc.)
+- **google-cloud-*** - GCP services (BigQuery, Cloud Storage, Vertex AI)
+
+### Scientific Computing
+
+- **SciPy** - Scientific algorithms and optimization
+- **SymPy** - Symbolic mathematics
+- **NetworkX** - Graph algorithms and analysis
+
+The pattern is straightforward: your F# service handles core domain logic and type-safe
+business rules, while specific endpoints delegate to a FastAPI service for capabilities
+where Python dominates. This is especially powerful for AI/ML workloads where the Python
+ecosystem is unmatched.
 *)

chapters/GettingStarted.fs

@@ -3,7 +3,7 @@ module GettingStarted
 (**
 # Getting Started with Fable.Python
 
-Let's set up a Fable.Python project from scratch and get our first F# code running as Python.
+In this section we will set up a Fable.Python project from scratch and get our first F# code running as Python.
 
 ## Prerequisites
 
@@ -12,7 +12,8 @@ You'll need:
 - [.NET SDK](https://dotnet.microsoft.com/download) (6.0 or later. We recommend
   installing the latest LTS version, currently .NET 10)
 - [Python 3.12+](https://www.python.org/downloads/) (Fable targets Python 3.12 or higher)
-- [uv](https://docs.astral.sh/uv/) (recommended) - A fast Python package manager written in Rust
+- [uv](https://docs.astral.sh/uv/) (recommended) - A fast Python package manager written in Rust that
+  simplifies dependency management, virtual environments, and the installation of Python itself.
 
 If you don't have `uv` installed:
 
@@ -60,8 +61,9 @@ pip install "fable-library==5.0.0a21"
 
 ---
 
-**Note:** Version pinning matters. The fable-library version must match
-your Fable compiler version. PyPI uses `5.0.0a21` format instead of `5.0.0-alpha.21`.
+**Note:** Version pinning matters. The fable-library version must match your Fable
+compiler version. Note that PyPI uses `5.0.0a21` format instead of `5.0.0-alpha.21` for
+prerelease alpha releases.
 
 ---
 
@@ -136,6 +138,6 @@ my-fable-python/
 
 ## Next Steps
 
-Now that you have a working setup, let's explore how to interact with Python
-libraries in the next chapter on **Bindings**.
+Now that you have a working setup, let's see how we can interact with Python
+libraries by using **Bindings**.
 *)

chapters/Interop.fs

@@ -3,8 +3,7 @@ module Interop
 (**
 # Python Interop
 
-Now that you have a Fable.Python project set up, let's explore how to work
-with Python libraries and the existing bindings in the Fable.Python ecosystem.
+With a Fable.Python project set up, we can start to work with Python libraries and the existing bindings in the Fable.Python ecosystem.
 
 ## The Fable.Python Library
 
@@ -427,7 +426,7 @@ let loadConfig (path: string) =
 (**
 ## What's Next?
 
-Now you know how to use existing Python bindings and core interop features.
-In the next chapter, we'll learn how to create your own bindings for
-Python libraries that don't have F# bindings yet.
+Now you know how to use existing Python bindings and core interop features. In the next
+chapter we will see how you can create your own bindings for Python libraries that don't
+have F# bindings yet.
 *)