Added examples (#29)

Closes #27 

Signed-off-by: Steve Winslow <swinslow@gmail.com>

1 files changed, 68 insertions, 0 deletions

diff --git a/examples/2-load-save/example_load_save.go b/examples/2-load-save/example_load_save.go
new file mode 100644
index 0000000..4a5cfc6
--- /dev/null
+++ b/examples/2-load-save/example_load_save.go
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+
+// Example for: *tvloader*, *tvsaver*
+
+// This example demonstrates loading an SPDX tag-value file from disk into memory,
+// and re-saving it to a different file on disk.
+
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/swinslow/spdx-go/v0/tvloader"
+	"github.com/swinslow/spdx-go/v0/tvsaver"
+)
+
+func main() {
+
+	// check that we've received the right number of arguments
+	args := os.Args
+	if len(args) != 3 {
+		fmt.Printf("Usage: %v <spdx-file-in> <spdx-file-out>\n", args[0])
+		fmt.Printf("  Load SPDX 2.1 tag-value file <spdx-file-in>, and\n")
+		fmt.Printf("  save it out to <spdx-file-out>.\n")
+		return
+	}
+
+	// open the SPDX file
+	fileIn := args[1]
+	r, err := os.Open(fileIn)
+	if err != nil {
+		fmt.Printf("Error while opening %v for reading: %v", fileIn, err)
+		return
+	}
+	defer r.Close()
+
+	// try to load the SPDX file's contents as a tag-value file, version 2.1
+	doc, err := tvloader.Load2_1(r)
+	if err != nil {
+		fmt.Printf("Error while parsing %v: %v", fileIn, err)
+		return
+	}
+
+	// if we got here, the file is now loaded into memory.
+	fmt.Printf("Successfully loaded %s\n", fileIn)
+
+	// we can now save it back to disk, using tvsaver.
+
+	// create a new file for writing
+	fileOut := args[2]
+	w, err := os.Create(fileOut)
+	if err != nil {
+		fmt.Printf("Error while opening %v for writing: %v", fileOut, err)
+		return
+	}
+	defer w.Close()
+
+	// try to save the document to disk as an SPDX tag-value file, version 2.1
+	err = tvsaver.Save2_1(doc, w)
+	if err != nil {
+		fmt.Printf("Error while saving %v: %v", fileOut, err)
+		return
+	}
+
+	// it worked
+	fmt.Printf("Successfully saved %s\n", fileOut)
+}