scripths

GHCi scripts for standalone execution and Markdown documentation.

scripths lets you write .ghci scripts with dependency management and run them as standalone programs — or embed executable Haskell code blocks in Markdown files and evaluate them notebook-style with captured output.

Features

• Standalone .ghci execution — Run GHCi scripts directly from the command line, with automatic dependency.
• Cabal metadata directives — Declare build-depends, default-extensions, and ghc-options inline using -- cabal: comments.
• Markdown notebooks — Execute Haskell code blocks inside Markdown files and render the output back into the document as block quotes.
• Smart GHCi rendering — Multi-line definitions are automatically wrapped in :{/:} blocks, and IO binds / Template Haskell splices are handled correctly as individual statements.

Installation

cabal install scripths

CLI Usage

scripths [-o FILE | --output=FILE] [-p DIR | --package DIR]... [--no-local-project] <script>

When -o / --output is provided for Markdown files, the result is written to that path. Otherwise it is printed to stdout. The file extension determines the mode. .ghci / hs files are parsed and executed as a standalone GHCi script. .md / .markdown files are processed as a notebook with captured output.

Requires GHC and cabal-install on your PATH.

Quick Start

Running a GHCi script

Create a file example.ghci:

double :: Int -> Int
double = (*2)

-- cabal: build-depends: text
:set -XOverloadedStrings
import qualified Data.Text as T

T.take 10 "hello"

double 5

Run it:

scripths example.ghci

Running a Markdown notebook

Create a file notebook.md:

# My Analysis

Some introductory prose.

```haskell
print (5 + 5)
```

Define some values:

```haskell
x = 10
y = 20
```

We can then add the values in the next block and
the output is embeded below.

```haskell
x + y
```

Run it and write the results to a new file:

scripths -o output.md notebook.md

Each Haskell code block is evaluated in order, and its output is inserted into the Markdown as a block quote beneath the code fence.

Cabal Metadata Directives

You can declare dependencies, language extensions, and GHC options directly inside your scripts using -- cabal: comments:

-- cabal: build-depends: text, containers
-- cabal: default-extensions: OverloadedStrings, TypeApplications
-- cabal: ghc-options: -Wall

Local packages

By default build-depends resolve from Hackage. To build a script or notebook against a local checkout instead — e.g. to document a library version that only exists on a branch — there are two mechanisms.

The enclosing project (zero-config)

If a script/notebook lives inside a cabal project and a build-depends names that project's package (or one of its sub-libraries, pkg:sublib), scripths builds against the local working tree automatically — so documenting your own repo just works:

scripths -o docs/MANUAL.md docs/base/MANUAL.md

Pass --no-local-project to suppress this and resolve every build-depends from Hackage instead — e.g. to verify the doc's examples against the released version of your package rather than the working tree. Explicit --package dirs are unaffected.

--package DIR

Point at another local checkout (a sibling package, or a sub-library project). DIR must be a package root (contain a .cabal); it is resolved to an absolute path at the invocation site, so nothing machine-specific is committed to the shared document. Repeatable.

scripths --package ../granite -o out.md in.md

Pinned git packages (source-repository-package)

To pin a pushed commit/tag reproducibly (and commit the pin into the shared document), declare a source-repository-package directive as <location> <ref> [subdir]:

-- cabal: source-repository-package: https://github.com/owner/repo v1.2.3
-- cabal: source-repository-package: https://github.com/owner/mono abc123 sub/dir

scripths writes these as source-repository-package stanzas in the generated cabal.project. Use a local checkout (above) for an unpushed branch, and a git pin for a pushed, reproducible reference.