0001

Status: Accepted (spago pin superseded by 0008: spago 0.21.0 → 1.x; the purs 0.15.16 and Lua 5.1 pins stand)

Context

Each fork needs a reproducible PureScript toolchain (purs, spago) and a Lua 5.1 runtime for the FFI checks. Early forks pinned their tools through easy-purescript-nix, which tracked purs 0.15.15 and pulled an unpinned spago. The compiler and the later forks moved to thomashoneyman/purescript-overlay, which packages exact purs and spago releases as nix attributes.

Decision

Every fork pins its toolchain through purescript-overlay: purs 0.15.16 (purs-bin.purs-0_15_16), spago 0.21.0 (spago-bin.spago-0_21_0), and a Lua 5.1 toolchain (lua51Packages). The dev shell also carries dhall, luacheck, luaformatter, nixfmt, and treefmt. The pslua compiler is a flake input tracking github:purescript-lua/purescript-lua.

Consequences

• One flake.nix shape across the set. Converting a fork is copying the canonical flake.nix and running nix flake update.
• purs and spago versions are exact and shared through the binary caches.
• Keep flake.lock reasonably current. A long-stale pslua pin predates the output-directory and codegen fixes and breaks CI (see 0002, 0003).