Pseudocode-syntax AffineScript. The pseudocode you wrote in your algorithms textbook actually compiles and runs.
PseudoScript is AffineScript with its pseudo face pre-selected. If you learned algorithms from CLRS, Sedgewick, or any first-year course, you already know the syntax: function name(…) do … end, set x to expr, output expr, if condition then … else … end if, for x in list do … end for, is / is not, and / or / not, yes / no. The compiler checks that your resources (files, sockets, tokens, handles) are used exactly as many times as you declare — and proves it at compile time, while reporting errors in beginner-friendly vocabulary rather than compiler jargon.
This repo is a brand surface only. The compiler, type checker, borrow checker, and codegen all live in affinescript. This repo carries:
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Examples that match common textbook pseudocode (CLRS, Sedgewick, etc.)
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Documentation aimed at CS students and educators
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A
pseudoshim CLI that aliasesaffinescript --face pseudo -
Tutorial materials suitable for an intro algorithms course
examples/hello.affine:
-- face: pseudoscript
effect IO {
fn println(s: String) -> ();
}
function main() -{IO}-> () do
set greeting to "Hello, PseudoScript!"
output greeting
endfunction … do … end, set x to …, output x, is / is not, yes / no — all lower to canonical AffineScript and produce the same typed-wasm output as every other face. Errors come back in the vocabulary your textbook taught you ("`x` has not been defined. Declare it with set x to … or as a function parameter.") rather than compiler-jargon.
opam install affinescript
git clone https://github.com/hyperpolymath/pseudoscript
cd pseudoscriptThe affinescript binary does the work. The bin/pseudo shim in this repo just defaults the --face flag.
# Direct, via affinescript: affinescript eval --face pseudo examples/hello.affine affinescript compile --face pseudo examples/hello.affine -o hello.wasm # Or via the pseudo shim (same thing): ./bin/pseudo eval examples/hello.affine ./bin/pseudo compile examples/hello.affine -o hello.wasm # Or via the justfile: just run examples/hello.affine just preview examples/hello.affine # show the canonical lowering
Source files use the canonical .affine extension. The face is selected by the -- face: pseudoscript pragma on the first comment line, or by the --face pseudo flag.
PseudoScript is one of six established faces over the AffineScript core:
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AffineScript — the canonical face
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RattleScript — indentation / scripting style
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JaffaScript — JavaScript / TypeScript-style
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LucidScript — PureScript / Haskell-style
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CafeScripto — CoffeeScript-style
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PseudoScript — pseudocode-style (this repo)
All six share the canonical .affine extension and lower to the same AST. Errors are reported in face-appropriate vocabulary.
The catchment is smaller than RattleScript or JaffaScript by raw headcount, but unusually defensible. CS pedagogy is pseudocode-first by tradition; the gap between "what the textbook says" and "what compiles" has been there for fifty years. Every CS textbook on Earth uses pseudocode for examples, yet there’s no other language where the pseudocode you wrote in week 1 actually executes — Scratch is graphical-only, conventional scripting languages are closer but still impose their own keywords and ceremony. PseudoScript closes that gap, giving students a way to:
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Write the algorithm exactly as the textbook describes it.
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Get type errors in pedagogy-friendly language ("the if branch produces X but the else branch produces Y — both branches must produce the same type") instead of compiler jargon.
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Compile to typed-wasm and actually see the algorithm run.
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Migrate to a more conventional face (Rattle, Jaffa) once they’re comfortable with programming-as-distinct-from-pseudocode.
Alpha. The face transformer is implemented in affinescript/lib/pseudocode_face.ml. Known limitations are tracked in the affinescript faces README under "Known transformer gaps".