Land Data.Monoid and Data.Foldable

crates/psrs-driver/src/tests/foldable.rs

@@ -0,0 +1,56 @@
+//! The library's `Monoid` and `Foldable` classes.
+//!
+//! `foldMap` and `fold` are constrained by `Monoid`, so the two classes land
+//! together. These tests run the instances, not a second traversal: `Array`
+//! walks the compiler's index primitives, and `Maybe` and `Either` fold by
+//! cases.
+
+use super::*;
+
+#[test]
+fn monoid_identities_and_folds_run_under_wasmtime() {
+    let source = r#"
+module Main where
+
+import Prelude
+import Effect.Console (log)
+import Data.Monoid (mempty)
+import Data.Foldable (class Foldable, foldl, foldr, foldMap)
+import Data.Maybe (Maybe(..))
+import Data.Either (Either(..))
+
+data One a = One a
+
+instance foldableOne :: Foldable One where
+  foldr f z (One x) = f x z
+  foldl f z (One x) = f z x
+  foldMap f (One x) = f x
+
+checks :: Effect Unit
+checks = do
+  log (foldr (\x acc -> x <> acc) ":" ["a", "b"])
+  log (foldl (\acc x -> acc <> x) ":" ["a", "b"])
+  log (foldMap (\x -> x <> "!") ["a", "b"])
+  log (if arrayLength (mempty :: Array Int) == 0 then "empty-array" else "empty-array-wrong")
+  log (if (mempty :: Unit) == unit then "empty-unit" else "empty-unit-wrong")
+  log mempty
+  log (foldr (\x acc -> x <> acc) "z" (Right "r" :: Either Int String))
+  log (foldr (\x acc -> x <> acc) "z" (Left 1 :: Either Int String))
+  log (foldl (\acc x -> acc <> x) "z" (Just "m"))
+  log (foldMap (\x -> x) (Nothing :: Maybe String))
+  log (foldMap (\x -> x) (One "one"))
+  pure unit
+
+main = let ignored = runEffect checks in 0
+"#;
+    let Some(output) = run_with_wasmtime(source) else {
+        eprintln!("skipping: wasmtime is not installed");
+        return;
+    };
+    assert_eq!(output.status.code(), Some(0), "{output:?}");
+    assert_eq!(
+        output.stdout,
+        "ab:\n:ab\na!b!\nempty-array\nempty-unit\n\nrz\nz\nzm\n\none\n".as_bytes(),
+        "monoid identities and folds must match the class instances: {output:?}"
+    );
+}

crates/psrs-driver/src/tests/mod.rs

@@ -10,11 +10,13 @@ mod data_function;
 mod deriving;
 mod effect_arity;
 mod effects;
+mod foldable;
 mod guard_coverage;
 mod operators;
 mod partial_application;
 mod scalars;
 mod semigroup;
+mod show;
 
 fn lower_source_to_mir(source: &str) -> psrs_backend::mir::Module {
     let core = lower_source_to_core("Main.purs", source).expect("source should lower to Core");

crates/psrs-driver/src/tests/module_loader.rs

@@ -103,14 +103,17 @@ fn loads_the_standard_library_from_disk_in_trusted_order() {
             "Prelude",
             "Data.Function",
             "Data.Semigroup",
+            "Data.Monoid",
             "Data.Eq",
             "Data.Ord",
             "Data.Semiring",
+            "Data.Show",
             "Effect",
             "Effect.Console",
             "Test.Assert",
             "Data.Maybe",
             "Data.Either",
+            "Data.Foldable",
             "WASI.Resource",
             "WASI.IO",
             "WASI.Clock",
@@ -128,14 +131,17 @@ fn loads_the_standard_library_from_disk_in_trusted_order() {
             path.ends_with("lib/Prelude.purs")
                 || path.ends_with("lib/Data/Function.purs")
                 || path.ends_with("lib/Data/Semigroup.purs")
+                || path.ends_with("lib/Data/Monoid.purs")
                 || path.ends_with("lib/Data/Eq.purs")
                 || path.ends_with("lib/Data/Ord.purs")
                 || path.ends_with("lib/Data/Semiring.purs")
+                || path.ends_with("lib/Data/Show.purs")
                 || path.ends_with("lib/Effect.purs")
                 || path.ends_with("lib/Effect/Console.purs")
                 || path.ends_with("lib/Test/Assert.purs")
                 || path.ends_with("lib/Data/Maybe.purs")
                 || path.ends_with("lib/Data/Either.purs")
+                || path.ends_with("lib/Data/Foldable.purs")
                 || path.ends_with("lib/WASI/Resource.purs")
                 || path.ends_with("lib/WASI/IO.purs")
                 || path.ends_with("lib/WASI/Clock.purs")

crates/psrs-driver/src/tests/show.rs

@@ -0,0 +1,112 @@
+//! The library's `Show` class.
+//!
+//! These tests execute under Wasmtime. The strings are the official `Show`
+//! spellings: `true`/`false`, decimal `Int`, `unit`, quoted `Char` and
+//! `String` (with the official escapes), arrays without spaces, and `Number`
+//! with a trailing `.0` on an integer token.
+
+use super::*;
+
+#[test]
+fn show_renders_the_instances_the_corpus_prints() {
+    let source = r#"
+module Main where
+
+import Prelude
+import Effect.Console (log)
+
+checks :: Effect Unit
+checks = do
+  log (show true)
+  log (show false)
+  log (show 0)
+  log (show 42)
+  log (show (0 - 7))
+  log (show ((0 - 2147483647) - 1))
+  log (show unit)
+  log (show "hi")
+  log (show "a\"b")
+  log (show "line\n")
+  log (show 'a')
+  log (show '\n')
+  log (show '\'')
+  log (show [1, 2, 3])
+  log (show [1.0, 2.0])
+  log (show 0.0)
+  log (show 1.0)
+  log (show (numberNeg 2.0))
+  log (show 1.5)
+  log (show 0.5)
+  log (show 0.25)
+  log (show 10000000000.0)
+  log (show 1.0e21)
+  log (show 1.0e-5)
+  log (show "é")
+  log (show "cafés")
+  pure unit
+
+main = let ignored = runEffect checks in 0
+"#;
+    let Some(output) = run_with_wasmtime(source) else {
+        eprintln!("skipping: wasmtime is not installed");
+        return;
+    };
+    assert_eq!(output.status.code(), Some(0), "{output:?}");
+    let stdout = String::from_utf8_lossy(&output.stdout);
+    let expected = concat!(
+        "true\n",
+        "false\n",
+        "0\n",
+        "42\n",
+        "-7\n",
+        "-2147483648\n",
+        "unit\n",
+        "\"hi\"\n",
+        "\"a\\\"b\"\n",
+        "\"line\\n\"\n",
+        "'a'\n",
+        "'\\n'\n",
+        "'\\''\n",
+        "[1,2,3]\n",
+        "[1.0,2.0]\n",
+        "0.0\n",
+        "1.0\n",
+        "-2.0\n",
+        "1.5\n",
+        "0.5\n",
+        "0.25\n",
+        "10000000000.0\n",
+        "1e+21\n",
+        "0.00001\n",
+        "\"é\"\n",
+        "\"cafés\"\n",
+    );
+    assert_eq!(
+        stdout.as_ref(),
+        expected,
+        "stdout:\n{stdout}\nstderr:\n{}",
+        String::from_utf8_lossy(&output.stderr)
+    );
+}
+
+#[test]
+fn a_type_without_show_is_rejected() {
+    let source = r#"
+module Main where
+
+import Prelude
+
+data Box = Box
+
+main :: String
+main = show Box
+"#;
+    let errors = check_program_types_lenient_with_prelude(&[("Main.purs", source)])
+        .expect_err("Box is not a Show");
+    assert!(
+        errors
+            .iter()
+            .any(|error| error.diagnostic.code == Some("NoInstanceFound")),
+        "expected NoInstanceFound, got {errors:?}"
+    );
+}