php Smarty模板引擎之 if else的用法

作者：袖梨 2022-06-25

用法：
{if}{/if}

{if} {else}{/else}{/if}

解析引擎：

代码如下

复制代码

// if
$if_operators = array(">","="," $is_operator = false;
$pattern_if = "/{$left_tag}ifs+((.*?)){$right_tag}/";
preg_match_all($pattern_if,$content,$match_if);

if (isset($match_if[1]) && is_array($match_if[1])) {

foreach ($match_if[1] as $key_if=>$val_if) {
foreach ($if_operators as $if_operator) {
$items = explode($if_operator, $val_if);
if (count($items) == 2) {
$is_operator = true;
$shift_left = substr($items[0], 0,1);
$pop_left = substr($items[0], 1);
$shift_right = substr($items[1], 0,1);

$pop_right = substr($items[1], 1);
$left_var = $shift_left == '$'? '$this->var_tpl_arr["'.$pop_left.'"]':$items[0];
$right_var = $shift_right == '$'?'$this->var_tpl_arr["'.$pop_right.'"]':$items[1];
$content = str_replace($match_if[0][$key_if], "", $content);
break;
} else {
continue;
}
}
if (!$is_operator) {
$content = str_replace($match_if[0][$key_if], "", $content);
}
}
}

// if close
$pattern_if = "/{$left_tag}/if{$right_tag}/";
$replace_if = ";";
if (preg_match($pattern_if, $content)) {
$content = preg_replace($pattern_if, $replace_if, $content);
}

// else
$pattern_else = "/{$left_tag}else{$right_tag}/";
$replace_else = "";
if (preg_match($pattern_else, $content)) {
$content = preg_replace($pattern_else, $replace_else, $content);
}

// else close
$pattern_else = "/{$left_tag}/else{$right_tag}/";
$replace_else = "";
if (preg_match($pattern_else, $content)) {
$content = preg_replace($pattern_else, $replace_else, $content);
}

模板表示方法：

代码如下

复制代码

$var_left == {$var_left},$var_right == {$var_right}

test if >:$var_left>1

{if ($var_left>1)}
if > 条件成立！
{/if}

test if <:>

{if ($var_left if
{/if}

test if ==:$var_left==$va_right

{if ($var_left==$va_right)}
if == 条件成立！
{else}
if = 条件不成立！
{/if}

解析后的缓存文件：

代码如下	复制代码
$var_left == var_tpl_arr["var_left"];?>,$var_right == var_tpl_arr["var_right"];?> test if >:$var_left>1 var_tpl_arr["var_left"] > 1) { ?> if > 条件成立！www.111com.net> ;