Add pony-lint CI workflow and fix lint issues

Add the pony-lint workflow to run on PRs that touch .pony files.
Add Makefile lint target. Fix existing style issues.

Author: SeanTAllen

.github/workflows/pony-lint.yml

@@ -0,0 +1,24 @@
+name: pony-lint
+
+on:
+  pull_request:
+    paths:
+      - '**/*.pony'
+
+concurrency:
+  group: pony-lint-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  packages: read
+
+jobs:
+  pony-lint:
+    name: Lint Pony source
+    runs-on: ubuntu-latest
+    container:
+      image: ghcr.io/ponylang/shared-docker-ci-standard-builder:release
+    steps:
+      - uses: actions/checkout@v6.0.2
+      - name: Lint
+        run: make lint

Makefile

@@ -5,6 +5,7 @@ GET_DEPENDENCIES_WITH := corral fetch
 CLEAN_DEPENDENCIES_WITH := corral clean
 COMPILE_WITH := corral run -- ponyc
 BUILD_DOCS_WITH := corral run -- pony-doc
+LINT_WITH := corral run -- pony-lint
 
 BUILD_DIR ?= build/$(config)
 SRC_DIR := $(PACKAGE)
@@ -58,6 +59,10 @@ $(docs_dir): $(SOURCE_FILES)
 
 docs: $(docs_dir)
 
+lint:
+	$(GET_DEPENDENCIES_WITH)
+	$(LINT_WITH) .
+
 TAGS:
 	ctags --recurse=yes $(SRC_DIR)
 
@@ -66,4 +71,4 @@ all: test
 $(BUILD_DIR):
 	mkdir -p $(BUILD_DIR)
 
-.PHONY: all examples clean TAGS test test-one
+.PHONY: all examples clean lint TAGS test test-one

examples/wc/wc.pony

@@ -1,8 +1,11 @@
+"""
+Count lines from standard input, similar to `wc -l`.
+"""
+
 // in your code this `use` statement would be:
 // use "valbytes"
 use "../../valbytes"
 
-
 actor Main
   """
   A simple `wc -l` clone, counting lines of what it receives via stdin.
@@ -24,7 +27,7 @@ actor Main
         fun ref dispose() =>
           var num_lines = USize(0)
           while buf.size() > 0 do
-            match buf.find("\n")
+            match \exhaustive\ buf.find("\n")
             | (true, let line_idx: USize) =>
               num_lines = num_lines + 1
               buf = buf.drop(line_idx + 1)

valbytes/_siphash.pony

@@ -29,7 +29,6 @@ class ref SipHash24Streaming
   var _v1: U64 = 0
   var _v2: U64 = 0
   var _v3: U64 = 0
-
   var _size: USize = 0
 
   new ref create() =>
@@ -77,6 +76,9 @@ class ref SipHash24Streaming
     result
 
 primitive SipHash24
+  """
+  Compute a SipHash-2-4 over a `ReadSeq[U8]`.
+  """
 
   fun _k0(): U64 => U64(0x8A109C6B22D309FE)
   fun _k1(): U64 => U64(0x9F923FCCB57235E1)
@@ -97,10 +99,12 @@ primitive SipHash24
     t1 = t1 xor t2
     t2 = t2.rotl(32)
 
-
     (t0, t1, t2, t3)
 
   fun apply[T: ReadSeq[U8] #read](data: T): U64 =>
+    """
+    Hash `data` and return the 64-bit digest.
+    """
     let size = data.size()
     var b: U64  = (size << USize(56)).u64()
 
@@ -176,13 +180,15 @@ primitive SipHash24
       -1
     end
 
-
 class ref HalfSipHash24Streaming
+  """
+  Streaming HalfSipHash-2-4 for incremental U32 input.
+  """
+
   var _v0: U32 = 0
   var _v1: U32 = 0
   var _v2: U32 = 0
   var _v3: U32 = 0
-
   var _size: USize = 0
 
   new ref create() =>
@@ -199,13 +205,20 @@ class ref HalfSipHash24Streaming
     _size = 0
 
   fun ref update(m: U32) =>
+    """
+    Hash `m` and update the internal state.
+    """
     _v3 = _v3 xor m
     (_v0, _v1, _v2, _v3) = HalfSipHash24._sipround32(_v0, _v1, _v2, _v3)
     (_v0, _v1, _v2, _v3) = HalfSipHash24._sipround32(_v0, _v1, _v2, _v3)
     _v0 = _v0 xor m
     _size = _size + 4
 
   fun ref finish(): U32 =>
+    """
+    Compute the hash from accumulated data and
+    reset the internal state.
+    """
     let b  = (_size << USize(24)).u32()
     _v3 = _v3 xor b
     (_v0, _v1, _v2, _v3) = HalfSipHash24._sipround32(_v0, _v1, _v2, _v3)
@@ -221,6 +234,9 @@ class ref HalfSipHash24Streaming
     result
 
 primitive HalfSipHash24
+  """
+  Compute a HalfSipHash-2-4 over a `ReadSeq[U8]`.
+  """
 
   fun _k0(): U32 => U32(0x22D309FE)
   fun _k1(): U32 => U32(0x8A109C6B)
@@ -244,7 +260,9 @@ primitive HalfSipHash24
     (t0, t1, t2, t3)
 
   fun apply[T: ReadSeq[U8] #read](data: T): U32 =>
-
+    """
+    Hash `data` and return the 32-bit digest.
+    """
     let size = data.size()
     var b: U32  = (size << USize(24)).u32()