lint: linter for package docstrings (#59)

Fixes #38

script/lib.sh

@@ -0,0 +1,6 @@
+# Print an error message to the terminal.
+print_error() {
+    local red='\033[0;31m'
+    local nocolor='\033[0m'
+    printf "${red}error${nocolor}\t$1\n"
+}

script/lint

@@ -15,3 +15,6 @@ golangci-lint run ./... ./examples/...
 
 # Check asm declarations.
 asmdecl ./...
+
+# Custom linters.
+./script/linter/pkgdoc

script/linter/pkgdoc

@@ -0,0 +1,12 @@
+#!/bin/bash -e
+
+source script/lib.sh
+
+status=0
+pkgs=$(go list -f '{{if not .Doc}}{{.ImportPath}}{{end}}' ./...)
+for pkg in ${pkgs}; do
+    print_error "${pkg} missing docstring"
+    status=1
+done
+
+exit ${status}

tests/fixedbugs/issue50/doc.go

@@ -0,0 +1,2 @@
+// Package issue50 tests for 32-bit MOVD/MOVQ instruction forms.
+package issue50