From 17d50c83f2a4be7405fa151fb66620c132b01f0f Mon Sep 17 00:00:00 2001
From: Jesse Luehrs <doy@tozt.net>
Date: Thu, 4 Oct 2012 18:21:30 -0500
Subject: implement the built-in block helpers

---
 lib/Text/Handlebars.pm    |  31 ++++++++
 t/block-helper-builtins.t | 178 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 209 insertions(+)
 create mode 100644 t/block-helper-builtins.t

diff --git a/lib/Text/Handlebars.pm b/lib/Text/Handlebars.pm
index 11de467..71b1ac1 100644
--- a/lib/Text/Handlebars.pm
+++ b/lib/Text/Handlebars.pm
@@ -64,6 +64,37 @@ sub options {
     my $options = $class->SUPER::options(@_);
 
     $options->{compiler} = 'Text::Handlebars::Compiler';
+    $options->{function} = {
+        ($options->{function} ? %{ $options->{function} } : ()),
+        with => sub {
+            my ($context, $new_context, $options) = @_;
+            return $options->{fn}->($new_context);
+        },
+        each => sub {
+            my ($context, $list, $options) = @_;
+
+            my $ret = '';
+            for my $new_context (@$list) {
+                $ret .= $options->{fn}->($new_context);
+            }
+
+            return $ret;
+        },
+        if => sub {
+            my ($context, $conditional, $options) = @_;
+            if ($conditional) {
+                return $options->{fn}->($context);
+            }
+            return '';
+        },
+        unless => sub {
+            my ($context, $conditional, $options) = @_;
+            unless ($conditional) {
+                return $options->{fn}->($context);
+            }
+            return '';
+        },
+    },
 
     return $options;
 }
diff --git a/t/block-helper-builtins.t b/t/block-helper-builtins.t
new file mode 100644
index 0000000..338e067
--- /dev/null
+++ b/t/block-helper-builtins.t
@@ -0,0 +1,178 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+use lib 't/lib';
+use Test::More;
+use Test::Handlebars;
+
+render_ok(
+    <<'TEMPLATE',
+<div class="entry">
+  <h1>{{title}}</h1>
+
+  {{#with author}}
+  <h2>By {{firstName}} {{lastName}}</h2>
+  {{/with}}
+</div>
+TEMPLATE
+    {
+        title  => 'My first post!',
+        author => {
+            firstName => 'Charles',
+            lastName  => 'Jolley',
+        },
+    },
+    <<'RENDERED',
+<div class="entry">
+  <h1>My first post!</h1>
+
+  <h2>By Charles Jolley</h2>
+</div>
+RENDERED
+    "with helper"
+);
+
+{ local $TODO = "unimplemented"; local $SIG{__WARN__} = sub { };
+render_ok(
+    <<'TEMPLATE',
+<ul class="people_list">
+  {{#each people}}
+  <li>{{this}}</li>
+  {{/each}}
+</ul>
+TEMPLATE
+    {
+        people => [
+            "Yehuda Katz",
+            "Alan Johnson",
+            "Charles Jolley",
+        ],
+    },
+    <<'RENDERED',
+<ul class="people_list">
+  <li>Yehuda Katz</li>
+  <li>Alan Johnson</li>
+  <li>Charles Jolley</li>
+</ul>
+RENDERED
+    "each helper"
+);
+}
+
+render_ok(
+    <<'TEMPLATE',
+<div class="entry">
+  {{#if author}}
+  <h1>{{firstName}} {{lastName}}</h1>
+  {{/if}}
+</div>
+TEMPLATE
+    {},
+    <<'RENDERED',
+<div class="entry">
+</div>
+RENDERED
+    "if helper (false)"
+);
+
+render_ok(
+    <<'TEMPLATE',
+<div class="entry">
+  {{#if author}}
+  <h1>{{firstName}} {{lastName}}</h1>
+  {{/if}}
+</div>
+TEMPLATE
+    {
+        author    => 1,
+        firstName => "Yehuda",
+        lastName  => "Katz",
+    },
+    <<'RENDERED',
+<div class="entry">
+  <h1>Yehuda Katz</h1>
+</div>
+RENDERED
+    "if helper (true)"
+);
+
+{ local $TODO = "unimplemented";
+render_ok(
+    <<'TEMPLATE',
+<div class="entry">
+  {{#if author}}
+    <h1>{{firstName}} {{lastName}}</h1>
+  {{else}}
+    <h1>Unknown Author</h1>
+  {{/if}}
+</div>
+TEMPLATE
+    {},
+    <<'RENDERED',
+<div class="entry">
+    <h1>Unknown Author</h1>
+</div>
+RENDERED
+    "if/else helper (false)"
+);
+
+render_ok(
+    <<'TEMPLATE',
+<div class="entry">
+  {{#if author}}
+    <h1>{{firstName}} {{lastName}}</h1>
+  {{else}}
+    <h1>Unknown Author</h1>
+  {{/if}}
+</div>
+TEMPLATE
+    {
+        author    => 1,
+        firstName => "Yehuda",
+        lastName  => "Katz",
+    },
+    <<'RENDERED',
+<div class="entry">
+    <h1>Yehuda Katz</h1>
+</div>
+RENDERED
+    "if/else helper (true)"
+);
+}
+
+render_ok(
+    <<'TEMPLATE',
+<div class="entry">
+  {{#unless license}}
+  <h3 class="warning">WARNING: This entry does not have a license!</h3>
+  {{/unless}}
+</div>
+TEMPLATE
+    {},
+    <<'RENDERED',
+<div class="entry">
+  <h3 class="warning">WARNING: This entry does not have a license!</h3>
+</div>
+RENDERED
+    "unless helper (false)"
+);
+
+render_ok(
+    <<'TEMPLATE',
+<div class="entry">
+  {{#unless license}}
+  <h3 class="warning">WARNING: This entry does not have a license!</h3>
+  {{/unless}}
+</div>
+TEMPLATE
+    {
+        license => 1,
+    },
+    <<'RENDERED',
+<div class="entry">
+</div>
+RENDERED
+    "unless helper (true)"
+);
+
+done_testing;
-- 
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