Compiler: add support for #emit_yield

lib/papercraft/compiler.rb

@@ -158,7 +158,7 @@ def compile(template, initial_level = 0)
 
     def to_code
       pad = '  ' * @level
-      "#{pad}->(__buffer__#{args}) do\n#{prelude}#{@code_buffer}#{pad}  __buffer__\n#{pad}end"
+      "#{pad}->(__buffer__#{args}, &__block__) do\n#{prelude}#{@code_buffer}#{pad}  __buffer__\n#{pad}end"
     end
 
     def args
@@ -231,6 +231,8 @@ def parse_fcall(node, block = nil)
         return emit_html5(node, block)
       when :emit
         return emit_emit(node.children[1], block)
+      when :emit_yield
+        return emit_emit_yield
       when :text
         return emit_text_fcall(args.first)
       end
@@ -332,10 +334,14 @@ def emit_emit(args, block)
         name = value.children.first.to_s
         value = get_const(name)
         case value
-        when Papercraft::Template
+        when Papercraft::Template, Proc
+          value = Papercraft.html(&value) if value.is_a?(Proc)
           @sub_templates << value
           idx = @sub_templates.size - 1
-          emit_code("__sub_templates__[#{idx}].(__buffer__)\n")
+          @line_break = false
+          emit_code("__sub_templates__[#{idx}].(__buffer__)")
+          emit_code_block(block) if block
+          emit_code("\n")
         else
           emit_output { emit_literal(value) }
         end
@@ -349,6 +355,19 @@ def emit_emit(args, block)
       # end
     end
 
+    def emit_code_block(block)
+      emit_code(" {\n")
+      @level += 1
+      parse(block.children[2])
+      flush_emit_buffer
+      @level -= 1
+      emit_code("}")
+    end
+
+    def emit_emit_yield
+      emit_code("__block__.call\n")
+    end
+
     def emit_tag_attributes(atts)
       list = atts.children.first.children
       while true
@@ -454,7 +473,7 @@ def parse_integer(node)
       value = node.children.first
       emit_literal(value.inspect)
     end
-    
+
     def parse_true(node)
       emit_expression { emit_literal('true') }
     end
@@ -482,6 +501,10 @@ def parse_list(node, emit_array = true, range = nil)
 
     def parse_vcall(node)
       tag = node.children.first
+      case tag
+      when :emit_yield
+        return emit_emit_yield
+      end
       emit_tag(tag, nil)
     end
 

test/test_compiler.rb

@@ -63,7 +63,7 @@ def test_compiler_simple
 
     code = compiled_template_code(templ)
     expected = <<~RUBY
-      ->(__buffer__) do
+      ->(__buffer__, &__block__) do
         __buffer__ << "<h1>foo</h1><h2>bar</h2>"
         __buffer__
       end
@@ -79,7 +79,7 @@ def test_compiler_simple_with_attributes
 
     code = compiled_template_code(templ)
     expected = <<~RUBY
-      ->(__buffer__) do
+      ->(__buffer__, &__block__) do
         __buffer__ << "<h1 class=\\"foot\\">foo</h1><h2 id=\\"bar\\" onclick=\\"f(&quot;abc&quot;, &quot;def&quot;)\\">bar</h2>"
         __buffer__
       end
@@ -292,7 +292,7 @@ def test_text
 
     c = t.compile
     expected = <<~RUBY.chomp
-      ->(__buffer__) do
+      ->(__buffer__, &__block__) do
         __buffer__ << "foo&amp;bar"
         __buffer__ << CGI.escapeHTML((__baz__).to_s)
         __buffer__ << "boo"
@@ -331,12 +331,12 @@ def test_emit_template
   end
 end
 
-class SyntaxTest < Minitest::Test
+class CompilerSyntaxTest < Minitest::Test
   def template_body(body)
     body.chomp.lines.map { |l| "  #{l}" }.join
   end
 
-  def test_case
+  def test_compiler_syntax_case
     t = C { |x|
       case x
       when :foo
@@ -359,7 +359,7 @@ def test_empty_template
     assert_equal '', t.render
   end
 
-  def test_tag_content_expr
+  def test_compiler_syntax_tag_content_expr
     t = c {
       p (1 + 2)
     }
@@ -372,7 +372,7 @@ def test_tag_content_expr
     assert_equal '<p>3</p>', t.to_proc.render
   end
 
-  def test_tag_content_var
+  def test_compiler_syntax_tag_content_var
     foo = 42
     t = c {
       p foo
@@ -387,7 +387,7 @@ def test_tag_content_var
 
   FOO = 43
 
-  def test_tag_content_const
+  def test_compiler_syntax_tag_content_const
     t = c {
       p FOO
     }
@@ -399,7 +399,7 @@ def test_tag_content_const
     assert_equal '<p>43</p>', t.to_proc.render
   end
 
-  def test_method_chain
+  def test_compiler_syntax_method_chain
     t = c {
       1.next.next.next
       p 2.next.next.next
@@ -413,7 +413,7 @@ def test_method_chain
     assert_equal '<p>5</p>', t.to_proc.render
   end
 
-  def test_ivar
+  def test_compiler_syntax_ivar
     @foo = 'bar'
 
     t = c {
@@ -427,7 +427,7 @@ def test_ivar
     assert_equal '<p>bar</p>', t.to_proc.render
   end
 
-  def test_sub_template_with_args
+  def test_compiler_syntax_sub_template_with_args
     sub = ->(x) {
       p x
     }
@@ -445,4 +445,22 @@ def test_sub_template_with_args
     assert_equal template_body(expected), t.code_buffer.chomp
     assert_equal '<div><p>42</p></div>', t.to_proc.render
   end
+
+  T1 = ->() { div { emit_yield } }
+
+  def test_compiler_syntax_emit_yield
+    t = c {
+      emit(T1) {
+        p 'foo'
+      }
+    }
+
+    expected = <<~RUBY
+      __sub_templates__[0].(__buffer__) {
+        __buffer__ << \"<p>foo</p>\"
+      }
+    RUBY
+    assert_equal template_body(expected), t.code_buffer.chomp
+    assert_equal '<div><p>foo</p></div>', t.to_proc.render
+  end
 end