Added file struct that satisfies io/fs.File

This will be used to abstract os.File and enable error reporting.

file/file.go

@@ -0,0 +1,60 @@
+package file
+
+import "os"
+import "path/filepath"
+
+type File struct {
+	path        string
+	moduleName  string
+	file        *os.File
+	currentLine int
+	lines       [][]byte
+}
+
+// Open opens the file specified by path and returns a new File struct. The
+// module name is automatically inferred through hte file's parent directory.
+func Open (path string) (file *File, err error) {
+	file = &File {
+		path:       path,
+		moduleName: filepath.Dir(path),
+		lines:      [][]byte { []byte { } },
+	}
+
+	file.file, err = os.OpenFile(path, os.O_RDONLY, 0660)
+	if err != nil { return }
+
+	return
+}
+
+// Stat returns the FileInfo structure describing file. If there is an error, it
+// will be of type *PathError. 
+func (file *File) Stat () (fileInfo os.FileInfo, err error) {
+	return file.file.Stat()
+}
+
+// Read reads up to len(bytes) bytes from the File and stores them in bytes. It
+// returns the number of bytes read and any error encountered. At end of file,
+// Read returns 0, io.EOF. This method stores all data read into the file struct
+// so it can be used later for error reporting.
+func (file *File) Read (bytes []byte) (amountRead int, err error) {
+	amountRead, err = file.file.Read(bytes)
+
+	for _, char := range bytes {
+		if char == '\n' {
+			file.lines = append(file.lines, []byte { })
+			file.currentLine ++
+		} else {
+			file.lines[file.currentLine] = append (
+				file.lines[file.currentLine],
+				bytes...)
+		}
+	}
+	
+	return
+}
+
+// Close closes the file. After the file is closed, data that has been read will
+// still be retained, and errors can be reported.
+func (file *File) Close () {
+	file.file.Close()
+}