Add Abs method to Document

document.go

@@ -3,6 +3,7 @@ package step
 import "io"
 import "time"
 import "strings"
+import "path/filepath"
 import "html/template"
 
 // Document represents a STEP file.
@@ -54,6 +55,26 @@ func (this *Document) Environment () *Environment {
 	return this.environment
 }
 
+// Abs returns an absolute representation of the given path. If the path is an
+// absolute path already, it is returned as-is. If the path is a relative path,
+// it is treated as relative to the current working directory. If the path is an
+// absolute path beginning with "." or "..", it is treated as relative to this
+// document. The result is cleaned.
+func (this *Document) Abs (name string) (string, error) {
+	if filepath.IsAbs(name) {
+		return filepath.Clean(name), nil
+	}
+	if strings.HasPrefix(name, ".") {
+		directory := this.name
+		ext := filepath.Ext(directory)
+		if ext != "" {
+			directory = filepath.Dir(directory)
+		}
+		return filepath.Abs(filepath.Join(directory, name))
+	}
+	return filepath.Abs(name)
+}
+
 // ExecutionData is data made available to documents as they are being exeucted.
 type ExecutionData struct {
 	Data any               // Custom data

document_test.go

@@ -0,0 +1,33 @@
+package step
+
+import "os"
+import "testing"
+import "path/filepath"
+
+func TestDocumentAbs (test *testing.T) {
+	document := Document {
+		name: "foo/bar.step",
+	}
+	cwd, err := os.Getwd()
+	if err != nil { test.Fatal(err) }
+	path1, err := document.Abs("thing.step")
+	if err != nil { test.Fatal(err) }
+	path2, err := document.Abs("thing/other.step")
+	if err != nil { test.Fatal(err) }
+	path3, err := document.Abs("./thing/other.step")
+	if err != nil { test.Fatal(err) }
+	path4, err := document.Abs("../thing/other.step")
+	if err != nil { test.Fatal(err) }
+	path5, err := document.Abs("/something/thing")
+	if err != nil { test.Fatal(err) }
+	test.Log(path1)
+	if path1 != filepath.Join(cwd, "thing.step") { test.Fatal("incorrect path") }
+	test.Log(path2)
+	if path2 != filepath.Join(cwd, "thing/other.step") { test.Fatal("incorrect path") }
+	test.Log(path3)
+	if path3 != filepath.Join(cwd, "foo/thing/other.step") { test.Fatal("incorrect path") }
+	test.Log(path4)
+	if path4 != filepath.Join(cwd, "thing/other.step") { test.Fatal("incorrect path") }
+	test.Log(path5)
+	if path5 != "/something/thing" { test.Fatal("incorrect path") }
+}