Horizon.Config.Types

A Hackage/package name: non-empty, no whitespace.

A GHC compiler spec, e.g. ghc-9.10.1 or ghc-10.0.x: non-empty and beginning with ghc, which is all a config can meaningfully name here.

A package version, e.g. 2.2.3.0: non-empty, only digits and dots. (x components as in an lts pin are a branch, not a package version, so a package Version is strictly numeric.)

A git commit revision: a hex string (a full 40-char SHA-1 or an unambiguous prefix of at least 7). This is what a flake pin locks to, so a non-hex value here is exactly the mistake worth catching early.

A git ref: a branch or tag name, e.g. lts/ghc-10.0.x or 0.24.0. Non-empty, no whitespace; the human-readable branch a Revision is on.

A URL (git repo or tarball): non-empty, no whitespace.

A subdirectory within a repo or tarball: non-empty, no whitespace. (The host still parses it into a real relative directory; this only rules out the obviously-bad literal at the DSL surface.)

A cabal flag name: non-empty, no whitespace.

A target platform as cabal names it, ARCH-OS (javascript-ghcjs, x86_64-linux): an architecture of letters, digits and underscores, a dash, then the operating system. Whether cabal knows the architecture and the system is the host's check, which has cabal's tables.

A Hackage index state, as cabal spells one: a UTC time to the second, 2025-03-01T00:00:00Z. Only the index entries published by then are read, so a later revision cannot change what the set renders. The literal must be the time's canonical spelling, which is the one form cabal's index-state and cabal2nix's snapshot both accept.

A repository on a forge, named by host and path with no scheme: nixlab.openfp.netpackage-setshaskell/horizon-core. The host is part of the path so a config names the whole location and the generator holds no forge of its own. Two or more segments, none empty, . or ..; a host with a dot; nothing a URL would read as a scheme, query or fragment; and a last segment, the repository, that is a SetName, since a toolchain base is the flake input named for its repository.

The name a package set is known by, which is also its flake input in a set layered on it: a letter, then letters, digits, dashes and underscores.

The name a config gives a secure cabal repository, which is also the name cabal keeps the repository's index under (packages/NAME): letters, digits, dots, dashes and underscores, e.g. nixlab.

A root key of a secure repository, as cabal's root-keys lists it: the key id, 64 lowercase hex digits.

A licence, as one SPDX licence identifier: MIT, BSD-3-Clause, Apache-2.0, GPL-3.0-or-later. Letters, digits, ., - and +, beginning with a letter; whether SPDX lists it is the generator's check.

The language a generated cabal declares as its default-language.

The language as cabal spells it.

One GHC extension a generated cabal turns on by default (default-extensions): OverloadedStrings, BlockArguments, or a No-prefixed one that turns it off. A capitalised identifier; whether GHC knows it is the generator's check.

The warnings contract of a repository's Haskell builds. werrorwolf is the estate's: every package also builds as a check with -Werror on top of its -Weverything. none declares no contract.

The contract as the warnings verb spells it.

A Haskell module name as cabal lists one: dot-separated components, each a capitalised identifier (Tint.Lexer.Cabal).

The name of a test suite, as cabal names a component: words of letters and digits joined by -, each word holding a letter (laws, golden-files).

The file a test suite runs, relative to its source directory, as cabal's main-is names it: Main.hs, Laws.hs, Golden/Main.hs. No empty, . or .. segment and no leading /; ends in .hs.

A backend a package is built for: the native code generator, or GHC's JavaScript backend.

The backend as the backend verb spells it.