Partial arguments

lib/ruby-handlebars/parser.rb

@@ -11,6 +11,7 @@ class Parser < Parslet::Parser
     rule(:ocurly)      { str('{')}
     rule(:ccurly)      { str('}')}
     rule(:pipe)        { str('|')}
+    rule(:eq)          { str('=')}
 
 
     rule(:docurly)     { ocurly >> ocurly }
@@ -50,6 +51,9 @@ class Parser < Parslet::Parser
     }
     rule(:parameters)  { parameter >> (space >> parameter).repeat }
 
+    rule(:argument)    { identifier.as(:key) >> space? >> eq >> space? >> parameter.as(:value) }
+    rule(:arguments)   { argument >> (space >> argument).repeat }
+
     rule(:unsafe_helper) { docurly >> space? >> identifier.as(:unsafe_helper_name) >> (space? >> parameters.as(:parameters)).maybe >> space? >> dccurly }
     rule(:safe_helper) { tocurly >> space? >> identifier.as(:safe_helper_name) >> (space? >> parameters.as(:parameters)).maybe >> space? >> tccurly }
 
@@ -98,6 +102,8 @@ class Parser < Parslet::Parser
       space? >>
       identifier.as(:partial_name) >>
       space? >>
+      arguments.as(:arguments).maybe >>
+      space? >>
       dccurly
     }
 

lib/ruby-handlebars/tree.rb

@@ -78,6 +78,15 @@ def _eval(context)
       end
     end
 
+    class PartialWithArgs < TreeItem.new(:partial_name, :arguments)
+      def _eval(context)
+        [arguments].flatten.map(&:values).map do |vals| 
+          context.add_item vals.first.to_s, vals.last._eval(context)
+        end
+        context.get_partial(partial_name.to_s).call
+      end
+    end
+
     class Block < TreeItem.new(:items)
       def _eval(context)
         items.map {|item| item._eval(context)}.join()
@@ -162,6 +171,13 @@ class Transform < Parslet::Transform
     ) {
       Tree::AsHelper.new(name, parameters, as_parameters, block_items, else_block_items)
     }
+
+    rule(
+      partial_name: simple(:partial_name),
+      arguments: subtree(:arguments)
+    ) {
+      Tree::PartialWithArgs.new(partial_name, arguments)
+    }
 
     rule(partial_name: simple(:partial_name)) {Tree::Partial.new(partial_name)}
     rule(block_items: subtree(:block_items)) {Tree::Block.new(block_items)}

spec/handlebars_spec.rb

@@ -61,6 +61,27 @@ def evaluate(template, args = {})
         hbs.register_partial('brackets', "[{{name}}]")
         expect(evaluate("Hello {{> brackets}}", {name: 'world'})).to eq("Hello [world]")
       end
+
+      it 'with a string argument' do
+        hbs.register_partial('with_args', "[{{name}}]")
+        expect(evaluate("Hello {{> with_args name='jon'}}")).to eq("Hello [jon]")
+      end
+
+      it 'with string arguments' do
+        hbs.register_partial('with_args', "[{{fname}} {{lname}}]")
+        expect(evaluate("Hello {{> with_args fname='jon' lname='doe'}}")).to eq("Hello [jon doe]")
+      end
+
+      it 'with variables in arguments' do
+         hbs.register_partial('with_args', "[{{fname}} {{lname}}]")
+        expect(evaluate("Hello {{> with_args fname='jon' lname=last_name}}", {last_name: 'doe'})).to eq("Hello [jon doe]")
+      end
+
+      it 'with a helper as an argument' do
+        hbs.register_helper('wrap_parens') {|context, value| "(#{value})"}
+        hbs.register_partial('with_args', "[{{fname}} {{lname}}]")
+        expect(evaluate("Hello {{> with_args fname='jon' lname=(wrap_parens 'doe')}}")).to eq("Hello [jon (doe)]")
+      end
     end
 
     context 'helpers' do