⚠️ Marker Parsing and Structure

.gitignore

@@ -11,4 +11,8 @@
 # Output of the go coverage tool, specifically when used with LiteIDE
 *.out
 
+# editor stuff
 .idea
+*.swp
+*.swo
+*~

pkg/loader/doc.go

@@ -0,0 +1,60 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package loader defines helpers for loading packages from sources.  It wraps
+// go/packages, allow incremental loading of source code and manual control
+// over which packages get type-checked.  This allows for faster loading in
+// cases where you don't actually care about certain imports.
+//
+// Because it uses go/packages, it's modules-aware, and works in both modules-
+// and non-modules environments.
+//
+// Loading
+//
+// The main entrypoint for loading is LoadRoots, which traverse the package
+// graph starting at the given patterns (file, package, path, or ...-wildcard,
+// as one might pass to go list).  Packages beyond the roots can be accessed
+// via the Imports() method.  Packages are initially loaded with export data
+// paths, filenames, and imports.
+//
+// Packages are suitable for comparison, as each unique package only ever has
+// one *Package object returned.
+//
+// Syntax and TypeChecking
+//
+// ASTs and type-checking information can be loaded with NeedSyntax and
+// NeedTypesInfo, respectively.  Both are idempotent -- repeated calls will
+// simply re-use the cached contents.  Note that NeedTypesInfo will *only* type
+// check the current package -- if you want to type-check imports as well,
+// you'll need to type-check them first.
+//
+// Reference Pruning and Recursive Checking
+//
+// In order to type-check using only the packages you care about, you can use a
+// TypeChecker.  TypeChecker will visit each top-level type declaration,
+// collect (optionally filtered) references, and type-check references
+// packages.
+//
+// Errors
+//
+// Errors can be added to each package.  Use ErrFromNode to create an error
+// from an AST node.  Errors can then be printed (complete with file and
+// position information) using PrintErrors, optionally filtered by error type.
+// It's generally a good idea to filter out TypeErrors when doing incomplete
+// type-checking with TypeChecker.  You can use MaybeErrList to return multiple
+// errors if you need to return an error instead of adding it to a package.
+// AddError will later unroll it into individual errors.
+package loader

pkg/loader/errors.go

@@ -0,0 +1,63 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package loader
+
+import (
+	"fmt"
+	"go/ast"
+	"go/token"
+)
+
+// PositionedError represents some error with an associated position.
+// The position is tied to some external token.FileSet.
+type PositionedError struct {
+	Pos token.Pos
+	error
+}
+
+// ErrFromNode returns the given error, with additional information
+// attaching it to the given AST node.  It will automatically map
+// over error lists.
+func ErrFromNode(err error, node ast.Node) error {
+	if asList, isList := err.(ErrList); isList {
+		resList := make(ErrList, len(asList))
+		for i, baseErr := range asList {
+			resList[i] = ErrFromNode(baseErr, node)
+		}
+		return resList
+	}
+	return PositionedError{
+		Pos:   node.Pos(),
+		error: err,
+	}
+}
+
+// MaybeErrList constructs an ErrList if the given list of
+// errors has any errors, otherwise returning nil.
+func MaybeErrList(errs []error) error {
+	if len(errs) == 0 {
+		return nil
+	}
+	return ErrList(errs)
+}
+
+// ErrList is a list of errors aggregated together into a single error.
+type ErrList []error
+
+func (l ErrList) Error() string {
+	return fmt.Sprintf("%v", []error(l))
+}