Added full support and documentation for ternary operator.

Fixes #881

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - Added support for PHP8.2
 - Added a new way to extend Smarty functionality using `Smarty::addExtension()`
+- Full support for ternary `{$test ? $a : $b}` and `{$var ?: $alternative}` [#881](https://github.com/smarty-php/smarty/issues/881)
 
 ### Changed
 - All Smarty code is now in the \Smarty namespace. For simple use-cases, you only need to add

docs/designers/language-basic-syntax/index.md

@@ -26,8 +26,8 @@ The basis components of the Smarty syntax are:
 
 - [Comments](language-syntax-comments.md)
 - [Variables](language-syntax-variables.md)
+- [Operators](language-syntax-operators.md)
 - [Functions](language-syntax-functions.md)
 - [Attributes](language-syntax-attributes.md)
 - [Quotes](language-syntax-quotes.md)
-- [Math](language-math.md)
 - [Escaping](language-escaping.md)

docs/designers/language-basic-syntax/language-math.md

@@ -1,28 +0,0 @@
-# Math
-
-Math can be applied directly to variable values.
-
-## Examples
-```smarty
-{$foo+1}
-
-{$foo*$bar}
-
-{* some more complicated examples *}
-
-{$foo->bar-$bar[1]*$baz->foo->bar()-3*7}
-
-{if ($foo+$bar.test%$baz*134232+10+$b+10)}
-
-{$foo|truncate:"`$fooTruncCount/$barTruncFactor-1`"}
-
-{assign var="foo" value="`$foo+$bar`"}
-```
-      
-> **Note**
->
-> Although Smarty can handle some very complex expressions and syntax,
-> it is a good rule of thumb to keep the template syntax minimal and
-> focused on presentation. If you find your template syntax getting too
-> complex, it may be a good idea to move the bits that do not deal
-> explicitly with presentation to PHP by way of plugins or modifiers.

docs/designers/language-basic-syntax/language-syntax-operators.md

@@ -0,0 +1,50 @@
+# Operators
+
+## Basic
+
+Various basic operators can be applied directly to variable values.
+
+## Examples
+```smarty
+{$foo + 1}
+
+{$foo * $bar}
+
+{$foo->bar - $bar[1] * $baz->foo->bar() -3 * 7}
+
+{if ($foo + $bar.test % $baz * 134232 + 10 + $b + 10)}
+    ...
+{/if}
+
+{$foo = $foo + $bar}
+```
+
+> **Note**
+>
+> Although Smarty can handle some very complex expressions and syntax,
+> it is a good rule of thumb to keep the template syntax minimal and
+> focused on presentation. If you find your template syntax getting too
+> complex, it may be a good idea to move the bits that do not deal
+> explicitly with presentation to PHP by way of plugins or modifiers.
+
+## Ternary
+You can use the `?:` (or ternary) operator to test one expression and present the value
+of the second or third expression, based on the result of te test.
+
+In other words:
+```smarty
+{$test ? "OK" : "FAIL"}
+```
+will result in OK if `$test` is set to true, and in FAIL otherwise.
+
+There is also a shorthand `?:` operator:
+```smarty
+{$myVar ?: "empty"}
+```
+will result in 'empty' if `$myVar` is not set or set to something that evaluates to false, such as an empty string.
+If `$myVar` is set to something that evaluates to true, the value of `$myVar` is returned. So, the following will 
+return 'hello':
+```smarty
+{$myVar="hello"}
+{$myVar ?: "empty"}
+```

src/Parser/TemplateParser.y

@@ -672,14 +672,23 @@ expr(res)        ::= expr(e1) ISIN value(v).  {
 //
 // ternary
 //
-ternary(res)        ::= OPENP expr(v) CLOSEP  QMARK DOLLARID(e1) COLON  expr(e2). {
+ternary(res)        ::= expr(v) QMARK DOLLARID(e1) COLON  expr(e2). {
     res = v.' ? '. $this->compiler->compileVariable('\''.substr(e1,1).'\'') . ' : '.e2;
 }
 
-ternary(res)        ::= OPENP expr(v) CLOSEP  QMARK  expr(e1) COLON  expr(e2). {
+ternary(res)        ::= expr(v) QMARK value(e1) COLON expr(e2). {
     res = v.' ? '.e1.' : '.e2;
 }
 
+ternary(res)        ::= expr(v) QMARK expr(e1) COLON expr(e2). {
+    res = v.' ? '.e1.' : '.e2;
+}
+
+// shorthand ternary
+ternary(res)        ::= expr(v) QMARK COLON expr(e2). {
+    res = v.' ?: '.e2;
+}
+
                  // value
 value(res)       ::= variable(v). {
     res = v;

tests/PHPUnit_Smarty.php

@@ -100,7 +100,7 @@ class PHPUnit_Smarty extends PHPUnit\Framework\TestCase
      *
      * @param null $dir working directory
      */
-    public function setUpSmarty($dir = null)
+    public function setUpSmarty($dir)
     {
         static $s_dir;
         // set up current working directory

tests/UnitTests/TemplateSource/TernaryTest.php

@@ -0,0 +1,41 @@
+<?php
+
+class TernaryTest extends PHPUnit_Smarty {
+
+	public function setUp(): void
+	{
+		$this->setUpSmarty('/tmp');
+		$this->cleanDirs();
+	}
+
+	public function testTernaryTrue() {
+		$tpl = $this->smarty->createTemplate('string:{$a ? $b : $c}');
+		$tpl->assign('a', true);
+		$tpl->assign('b', 'B');
+		$tpl->assign('c', 'C');
+		$this->assertEquals('B', $this->smarty->fetch($tpl));
+	}
+
+	public function testTernaryFalse() {
+		$tpl = $this->smarty->createTemplate('string:{$a ? $b : $c}');
+		$tpl->assign('a', false);
+		$tpl->assign('b', 'B');
+		$tpl->assign('c', 'C');
+		$this->assertEquals('C', $this->smarty->fetch($tpl));
+	}
+
+	public function testShorthandTernaryTrue() {
+		$tpl = $this->smarty->createTemplate('string:{$a ?: $c}');
+		$tpl->assign('a', true);
+		$tpl->assign('c', 'C');
+		$this->assertEquals(true, $this->smarty->fetch($tpl));
+	}
+
+	public function testShorthandTernaryFalse() {
+		$tpl = $this->smarty->createTemplate('string:{$a ? $b : $c}');
+		$tpl->assign('a', false);
+		$tpl->assign('c', 'C');
+		$this->assertEquals('C', $this->smarty->fetch($tpl));
+	}
+
+}