diff --git a/changelog/939.md b/changelog/939.md
new file mode 100644
index 00000000..ae676749
--- /dev/null
+++ b/changelog/939.md
@@ -0,0 +1 @@
+- Add support for implode, substr and json_encode as modifiers/functions in templates [#939](https://github.com/smarty-php/smarty/issues/939)
\ No newline at end of file
diff --git a/src/Compile/Modifier/JsonEncodeModifierCompiler.php b/src/Compile/Modifier/JsonEncodeModifierCompiler.php
new file mode 100644
index 00000000..4f191a31
--- /dev/null
+++ b/src/Compile/Modifier/JsonEncodeModifierCompiler.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace Smarty\Compile\Modifier;
+
+/**
+ * Smarty json_encode modifier plugin
+ */
+class JsonEncodeModifierCompiler extends Base {
+
+	public function compile($params, \Smarty\Compiler\Template $compiler) {
+		return 'json_encode(' . $params[0] . (isset($params[1]) ? ', (int) ' . $params[1] : '') . ')';
+	}
+
+}
\ No newline at end of file
diff --git a/src/Compile/Modifier/SubstrModifierCompiler.php b/src/Compile/Modifier/SubstrModifierCompiler.php
new file mode 100644
index 00000000..8fb33ed7
--- /dev/null
+++ b/src/Compile/Modifier/SubstrModifierCompiler.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Smarty\Compile\Modifier;
+
+/**
+ * Smarty substr modifier plugin
+ */
+class SubstrModifierCompiler extends Base {
+
+	public function compile($params, \Smarty\Compiler\Template $compiler) {
+		return 'substr((string) ' . $params[0] . ', (int) ' . $params[1] .
+			(isset($params[2]) ? ', (int) ' . $params[2] : '') . ')';
+	}
+
+}
\ No newline at end of file
diff --git a/src/Compile/ModifierCompiler.php b/src/Compile/ModifierCompiler.php
index d07763bf..765e8376 100644
--- a/src/Compile/ModifierCompiler.php
+++ b/src/Compile/ModifierCompiler.php
@@ -43,16 +43,19 @@ class ModifierCompiler extends Base {
 		foreach ($parameter['modifierlist'] as $single_modifier) {
 			/* @var string $modifier */
 			$modifier = $single_modifier[0];
-			$single_modifier[0] = $output;
-			$params = implode(',', $single_modifier);
+
+
+			$modifier_params = array_values($single_modifier);
+
+			$modifier_params[0] = $output;
+			$params = implode(',', $modifier_params);
 
 			if (!is_object($compiler->getSmarty()->security_policy)
 				|| $compiler->getSmarty()->security_policy->isTrustedModifier($modifier, $compiler)
 			) {
 
 				if ($handler = $compiler->getModifierCompiler($modifier)) {
-					$output = $handler->compile($single_modifier, $compiler);
-
+					$output = $handler->compile($modifier_params, $compiler);
 				} elseif ($compiler->getSmarty()->getModifierCallback($modifier)) {
 					$output = sprintf(
 							'$_smarty_tpl->getSmarty()->getModifierCallback(%s)(%s)',
@@ -60,7 +63,7 @@ class ModifierCompiler extends Base {
 							$params
 						);
 				} elseif ($callback = $compiler->getPluginFromDefaultHandler($modifier, \Smarty\Smarty::PLUGIN_MODIFIERCOMPILER)) {
-					$output = (new \Smarty\Compile\Modifier\BCPluginWrapper($callback))->compile($single_modifier, $compiler);
+					$output = (new \Smarty\Compile\Modifier\BCPluginWrapper($callback))->compile($modifier_params, $compiler);
 				} elseif ($function = $compiler->getPluginFromDefaultHandler($modifier, \Smarty\Smarty::PLUGIN_MODIFIER)) {
 					if (!is_array($function)) {
 						$output = "{$function}({$params})";
diff --git a/src/Compiler/Configfile.php b/src/Compiler/Configfile.php
index 7297a62b..84c14f9e 100644
--- a/src/Compiler/Configfile.php
+++ b/src/Compiler/Configfile.php
@@ -65,8 +65,6 @@ class Configfile extends BaseCompiler {
 	 * @param Smarty $smarty global instance
 	 */
 	public function __construct(Smarty $smarty) {
-		$this->smarty = $smarty;
-		// get required plugins
 		$this->smarty = $smarty;
 		$this->config_data['sections'] = [];
 		$this->config_data['vars'] = [];
@@ -104,7 +102,7 @@ class Configfile extends BaseCompiler {
 			) . "\n",
 			$this
 		);
-		/* @var ConfigfileParser $this->parser */
+
 		$this->parser = new ConfigfileParser($this->lex, $this);
 		if ($this->smarty->_parserdebug) {
 			$this->parser->PrintTrace();
diff --git a/src/Extension/DefaultExtension.php b/src/Extension/DefaultExtension.php
index 070274c7..5ebcce47 100644
--- a/src/Extension/DefaultExtension.php
+++ b/src/Extension/DefaultExtension.php
@@ -28,6 +28,7 @@ class DefaultExtension extends Base {
 			case 'from_charset': $this->modifiers[$modifier] = new \Smarty\Compile\Modifier\FromCharsetModifierCompiler(); break;
 			case 'indent': $this->modifiers[$modifier] = new \Smarty\Compile\Modifier\IndentModifierCompiler(); break;
 			case 'isset': $this->modifiers[$modifier] = new \Smarty\Compile\Modifier\IssetModifierCompiler(); break;
+			case 'json_encode': $this->modifiers[$modifier] = new \Smarty\Compile\Modifier\JsonEncodeModifierCompiler(); break;
 			case 'lower': $this->modifiers[$modifier] = new \Smarty\Compile\Modifier\LowerModifierCompiler(); break;
 			case 'nl2br': $this->modifiers[$modifier] = new \Smarty\Compile\Modifier\Nl2brModifierCompiler(); break;
 			case 'noprint': $this->modifiers[$modifier] = new \Smarty\Compile\Modifier\NoPrintModifierCompiler(); break;
@@ -37,6 +38,7 @@ class DefaultExtension extends Base {
 			case 'strip': $this->modifiers[$modifier] = new \Smarty\Compile\Modifier\StripModifierCompiler(); break;
 			case 'strip_tags': $this->modifiers[$modifier] = new \Smarty\Compile\Modifier\StripTagsModifierCompiler(); break;
 			case 'strlen': $this->modifiers[$modifier] = new \Smarty\Compile\Modifier\StrlenModifierCompiler(); break;
+			case 'substr': $this->modifiers[$modifier] = new \Smarty\Compile\Modifier\SubstrModifierCompiler(); break;
 			case 'to_charset': $this->modifiers[$modifier] = new \Smarty\Compile\Modifier\ToCharsetModifierCompiler(); break;
 			case 'unescape': $this->modifiers[$modifier] = new \Smarty\Compile\Modifier\UnescapeModifierCompiler(); break;
 			case 'upper': $this->modifiers[$modifier] = new \Smarty\Compile\Modifier\UpperModifierCompiler(); break;
@@ -54,6 +56,7 @@ class DefaultExtension extends Base {
 			case 'debug_print_var': return [$this, 'smarty_modifier_debug_print_var'];
 			case 'escape': return [$this, 'smarty_modifier_escape'];
 			case 'explode': return [$this, 'smarty_modifier_explode'];
+			case 'implode': return [$this, 'smarty_modifier_implode'];
 			case 'mb_wordwrap': return [$this, 'smarty_modifier_mb_wordwrap'];
 			case 'number_format': return [$this, 'smarty_modifier_number_format'];
 			case 'regex_replace': return [$this, 'smarty_modifier_regex_replace'];
@@ -522,6 +525,27 @@ class DefaultExtension extends Base {
 		return explode($separator, $string ?? '', $limit ?? PHP_INT_MAX);
 	}
 
+	/**
+	 * Smarty implode modifier plugin
+	 * Type:     modifier
+	 * Name:     implode
+	 * Purpose:  join an array of values into a single string
+	 *
+	 * @param array   $values
+	 * @param string   $separator
+	 *
+	 * @return string
+	 */
+	public function smarty_modifier_implode($values, $separator = '')
+	{
+		if (is_array($separator)) {
+			trigger_error("Using implode with the separator first is deprecated. " .
+				"Call implode using the array first, separator second.", E_USER_DEPRECATED);
+			return implode((string) ($values ?? ''), (array) $separator);
+		}
+		return implode((string) ($separator ?? ''), (array) $values);
+	}
+
 	/**
 	 * Smarty wordwrap modifier plugin
 	 * Type:     modifier
diff --git a/tests/UnitTests/SmartyMethodsTests/RegisterModifier/RegisterModifierTest.php b/tests/UnitTests/SmartyMethodsTests/RegisterModifier/RegisterModifierTest.php
index 267448d9..05ee7459 100644
--- a/tests/UnitTests/SmartyMethodsTests/RegisterModifier/RegisterModifierTest.php
+++ b/tests/UnitTests/SmartyMethodsTests/RegisterModifier/RegisterModifierTest.php
@@ -103,7 +103,8 @@ class RegisterModifierTest extends PHPUnit_Smarty
 
 	public function dataUnknownModifiers(): array {
 		return [
-			['{"blah"|substr:1:2}', 'la'],
+			['{" blah"|ltrim:" "}', 'blah'],
+			['{"blah"|strrev}', 'halb'],
 			['{"blah"|ucfirst}', 'Blah'],
 			['{"blah"|md5}', md5('blah')],
 		];
diff --git a/tests/UnitTests/TemplateSource/TagTests/PluginModifier/PluginModifierImplodeTest.php b/tests/UnitTests/TemplateSource/TagTests/PluginModifier/PluginModifierImplodeTest.php
new file mode 100644
index 00000000..71a4419d
--- /dev/null
+++ b/tests/UnitTests/TemplateSource/TagTests/PluginModifier/PluginModifierImplodeTest.php
@@ -0,0 +1,52 @@
+<?php
+/**
+ * Smarty PHPunit tests of modifier
+ */
+
+namespace UnitTests\TemplateSource\TagTests\PluginModifier;
+use PHPUnit_Smarty;
+
+class PluginModifierImplodeTest extends PHPUnit_Smarty
+{
+	public function setUp(): void
+	{
+		$this->setUpSmarty(__DIR__);
+	}
+
+	public function testDefault()
+	{
+		$tpl = $this->smarty->createTemplate('string:{$v|implode}');
+		$tpl->assign("v", ["1", "2"]);
+		$this->assertEquals("12", $this->smarty->fetch($tpl));
+	}
+	public function testWithSeparator()
+	{
+		$tpl = $this->smarty->createTemplate('string:{$v|implode:","}');
+		$tpl->assign("v", ["a", "b"]);
+		$this->assertEquals("a,b", $this->smarty->fetch($tpl));
+	}
+	/**
+	 * @deprecated
+	 */
+	public function testLegacyArgumentOrder()
+	{
+		$tpl = $this->smarty->createTemplate('string:{","|implode:$v}');
+		$tpl->assign("v", ["a", "b"]);
+		$this->assertEquals("a,b", $this->smarty->fetch($tpl));
+	}
+
+	public function testInConditional()
+	{
+		$tpl = $this->smarty->createTemplate('string:{if implode($v) == "abc"}good{else}bad{/if}');
+		$tpl->assign("v", ['a','b','c']);
+		$this->assertEquals("good", $this->smarty->fetch($tpl));
+	}
+
+	public function testInConditionalWithSeparator()
+	{
+		$tpl = $this->smarty->createTemplate('string:{if implode($v, "-") == "a-b-c"}good{else}bad{/if}');
+		$tpl->assign("v", ['a','b','c']);
+		$this->assertEquals("good", $this->smarty->fetch($tpl));
+	}
+
+}
diff --git a/tests/UnitTests/TemplateSource/TagTests/PluginModifier/PluginModifierJsonEncodeTest.php b/tests/UnitTests/TemplateSource/TagTests/PluginModifier/PluginModifierJsonEncodeTest.php
new file mode 100644
index 00000000..9a287812
--- /dev/null
+++ b/tests/UnitTests/TemplateSource/TagTests/PluginModifier/PluginModifierJsonEncodeTest.php
@@ -0,0 +1,72 @@
+<?php
+/**
+ * Smarty PHPunit tests of modifier
+ */
+
+namespace UnitTests\TemplateSource\TagTests\PluginModifier;
+use PHPUnit_Smarty;
+
+class PluginModifierJsonEncodeTest extends PHPUnit_Smarty
+{
+	public function setUp(): void
+	{
+		$this->setUpSmarty(__DIR__);
+	}
+
+	/**
+	 * @dataProvider dataForDefault
+	 */
+	public function testDefault($value, $expected)
+	{
+		$tpl = $this->smarty->createTemplate('string:{$v|json_encode}');
+		$tpl->assign("v", $value);
+		$this->assertEquals($expected, $this->smarty->fetch($tpl));
+	}
+
+	/**
+	 * @dataProvider dataForDefault
+	 */
+	public function testDefaultAsFunction($value, $expected)
+	{
+		$tpl = $this->smarty->createTemplate('string:{json_encode($v)}');
+		$tpl->assign("v", $value);
+		$this->assertEquals($expected, $this->smarty->fetch($tpl));
+	}
+
+	public function dataForDefault() {
+		return [
+			["abc", '"abc"'],
+			[["abc"], '["abc"]'],
+			[["abc",["a"=>2]], '["abc",{"a":2}]'],
+		];
+	}
+
+	/**
+	 * @dataProvider dataForForceObject
+	 */
+	public function testForceObject($value, $expected)
+	{
+		$tpl = $this->smarty->createTemplate('string:{$v|json_encode:16}');
+		$tpl->assign("v", $value);
+		$this->assertEquals($expected, $this->smarty->fetch($tpl));
+	}
+
+	/**
+	 * @dataProvider dataForForceObject
+	 */
+	public function testForceObjectAsFunction($value, $expected)
+	{
+		$tpl = $this->smarty->createTemplate('string:{json_encode($v,16)}');
+		$tpl->assign("v", $value);
+		$this->assertEquals($expected, $this->smarty->fetch($tpl));
+	}
+
+	public function dataForForceObject() {
+		return [
+			["abc", '"abc"'],
+			[["abc"], '{"0":"abc"}'],
+			[["abc",["a"=>2]], '{"0":"abc","1":{"a":2}}'],
+		];
+	}
+
+}
diff --git a/tests/UnitTests/TemplateSource/TagTests/PluginModifier/PluginModifierSubstrTest.php b/tests/UnitTests/TemplateSource/TagTests/PluginModifier/PluginModifierSubstrTest.php
new file mode 100644
index 00000000..cc59e107
--- /dev/null
+++ b/tests/UnitTests/TemplateSource/TagTests/PluginModifier/PluginModifierSubstrTest.php
@@ -0,0 +1,44 @@
+<?php
+/**
+ * Smarty PHPunit tests of modifier
+ */
+
+namespace UnitTests\TemplateSource\TagTests\PluginModifier;
+use PHPUnit_Smarty;
+
+class PluginModifierSubstrTest extends PHPUnit_Smarty
+{
+	public function setUp(): void
+	{
+		$this->setUpSmarty(__DIR__);
+	}
+
+	public function testDefault()
+	{
+		$tpl = $this->smarty->createTemplate('string:{$v|substr:1}');
+		$tpl->assign("v", "abc");
+		$this->assertEquals("bc", $this->smarty->fetch($tpl));
+	}
+
+	public function testTwoArguments()
+	{
+		$tpl = $this->smarty->createTemplate('string:{$v|substr:1:1}');
+		$tpl->assign("v", "abc");
+		$this->assertEquals("b", $this->smarty->fetch($tpl));
+	}
+
+	public function testNegativeOffset()
+	{
+		$tpl = $this->smarty->createTemplate('string:{$v|substr:-1}');
+		$tpl->assign("v", "abc");
+		$this->assertEquals("c", $this->smarty->fetch($tpl));
+	}
+
+	public function testInConditional()
+	{
+		$tpl = $this->smarty->createTemplate('string:{if substr($v, -1) == "c"}good{else}bad{/if}');
+		$tpl->assign("v", "abc");
+		$this->assertEquals("good", $this->smarty->fetch($tpl));
+	}
+
+}