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/*
* document-manipulation.c - Document manipulation example
*
* Demonstrates:
* - Reading values from a YAML document
* - Modifying existing values
* - Adding new fields to the document
* - Emitting with sorted keys
*
* Copyright (c) 2019-2025 Pantelis Antoniou <pantelis.antoniou@konsulko.com>
*
* SPDX-License-Identifier: MIT
*/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <libfyaml.h>
int main(int argc, char *argv[])
{
struct fy_document *fyd = NULL;
const char *input_file = (argc > 1) ? argv[1] : "invoice.yaml";
unsigned int invoice_nr;
char given_name[256];
int ret = EXIT_FAILURE;
// Create a default invoice if file doesn't exist
const char *default_invoice =
"invoice: 34843\n"
"date: 2001-01-23\n"
"bill-to:\n"
" given: Chris\n"
" family: Dumars\n"
" address:\n"
" lines: |\n"
" 458 Walkman Dr.\n"
" Suite #292\n"
"product:\n"
" - sku: BL394D\n"
" quantity: 4\n"
" description: Basketball\n"
" price: 450.00\n";
// Try to load from file, fall back to default
fyd = fy_document_build_from_file(NULL, input_file);
if (!fyd) {
fprintf(stderr, "Note: Creating document from default data\n");
fprintf(stderr, " (Create invoice.yaml or pass file as argument)\n\n");
fyd = fy_document_build_from_string(NULL, default_invoice, FY_NT);
if (!fyd) {
fprintf(stderr, "Failed to create document\n");
goto cleanup;
}
}
// Read current invoice number and customer name
int count = fy_document_scanf(fyd,
"/invoice %u "
"/bill-to/given %255s",
&invoice_nr, given_name);
if (count != 2) {
fprintf(stderr, "Failed to extract invoice data\n");
goto cleanup;
}
printf("Processing invoice #%u for %s\n\n", invoice_nr, given_name);
// Update invoice number (replaces existing value)
if (fy_document_insert_at(fyd, "/invoice", FY_NT,
fy_node_buildf(fyd, "%u", invoice_nr + 1))) {
fprintf(stderr, "Failed to update invoice number\n");
goto cleanup;
}
printf("Updated invoice number to %u\n", invoice_nr + 1);
// Add spouse field to bill-to
if (fy_document_insert_at(fyd, "/bill-to", FY_NT,
fy_node_buildf(fyd, "spouse: Jane"))) {
fprintf(stderr, "Failed to add spouse\n");
goto cleanup;
}
printf("Added spouse information\n");
// Add delivery address
if (fy_document_insert_at(fyd, "/bill-to", FY_NT,
fy_node_buildf(fyd,
"delivery-address:\n"
" street: 123 Main St\n"
" city: Springfield\n"
" state: IL\n"
" zip: 62701\n"))) {
fprintf(stderr, "Failed to add delivery address\n");
goto cleanup;
}
printf("Added delivery address\n");
// Emit updated document with sorted keys
printf("\n--- Updated Invoice ---\n");
if (fy_emit_document_to_fp(fyd, FYECF_DEFAULT | FYECF_SORT_KEYS, stdout)) {
fprintf(stderr, "Failed to emit document\n");
goto cleanup;
}
ret = EXIT_SUCCESS;
cleanup:
fy_document_destroy(fyd);
return ret;
}
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