Add method Field::asLineMarc()

CHANGELOG.md

@@ -6,6 +6,11 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased]
 
+### Added
+
+- Added new method `Field::asLineMarc()` to return a line mode Marc string
+  representation of the field.
+
 ### Fixed
 
 - Fixed the `Subject::getParts()` method.

src/Fields/Field.php

@@ -98,6 +98,36 @@ protected function toString($codes, $options = [])
         return $this->clean(implode($glue, $this->getSubfieldValues($codes)), $options);
     }
 
+    /**
+     * Return a line MARC representation of the field. If the field is deleted,
+     * null is returned.
+     *
+     * @param string $sep Subfield separator character, defaults to '$'
+     * @param string $blank Blank indicator character, defaults to ' '
+     * @return string|null.
+     */
+    public function asLineMarc($sep = '$', $blank = ' ')
+    {
+        if ($this->field->isEmpty()) {
+            return null;
+        }
+        $subfields = [];
+        foreach ($this->field->getSubfields() as $sf) {
+            $subfields[] = $sep . $sf->getCode() . ' ' . $sf->getData();
+        }
+        $tag = $this->field->getTag();
+        $ind1 = $this->field->getIndicator(1);
+        $ind2 = $this->field->getIndicator(2);
+        if ($ind1 == ' ') {
+            $ind1 = $blank;
+        }
+        if ($ind2 == ' ') {
+            $ind2 = $blank;
+        }
+
+        return "${tag} ${ind1}${ind2} " . implode(' ', $subfields);
+    }
+
     /**
      * Return the data value of the *first* subfield with a given code.
      *

tests/FieldsTest.php

@@ -84,4 +84,27 @@ public function testId()
             json_encode(['id' => $record->id])
         );
     }
+
+    public function testAsLineMarc()
+    {
+        $source = '<?xml version="1.0" encoding="UTF-8" ?>
+          <record xmlns="http://www.loc.gov/MARC21/slim">
+            <leader>99999cam a2299999 u 4500</leader>
+            <controlfield tag="001">98218834x</controlfield>
+            <datafield tag="020" ind1=" " ind2=" ">
+              <subfield code="q">h.</subfield>
+              <subfield code="c">Nkr 98.00</subfield>
+            </datafield>
+          </record>';
+
+        $record = Record::fromString($source);
+        $field = $record->isbns[0];
+
+        $this->assertEquals('020    $q h. $c Nkr 98.00', $field->asLineMarc());
+        $this->assertEquals('020    $$q h. $$c Nkr 98.00', $field->asLineMarc('$$'));
+        $this->assertEquals('020 ## $$q h. $$c Nkr 98.00', $field->asLineMarc('$$', '#'));
+
+        $field->delete();
+        $this->assertNull($field->asLineMarc());
+    }
 }