diff --git a/Makefile b/Makefile
index 7b02c9e..4bcd78e 100644
--- a/Makefile
+++ b/Makefile
@@ -24,5 +24,5 @@ format:
 
 .PHONY: spec
 spec: format
-	./crystal spec --no-debug --warnings all --error-on-warnings
+	./crystal spec --no-debug --warnings all --error-on-warnings --error-trace
 
diff --git a/spec/command_router_spec.cr b/spec/command_router_spec.cr
index dfd2154..681f001 100644
--- a/spec/command_router_spec.cr
+++ b/spec/command_router_spec.cr
@@ -2,13 +2,42 @@ require "./spec_helper"
 require "../src/cli/*"
 
 describe CLI::CommandRouter do
-  it "should handle simple command" do
+  it "should handle simple command as block" do
     router = CLI::CommandRouter.new
     x = 10
-    router.add "plus" do
+    router.add "plus" do |p|
       x += 5
     end
     router.handle "plus"
     x.should eq 15
   end
+
+  it "should handle simple command as proc" do
+    router = CLI::CommandRouter.new
+    x = 10
+    cb = ->(params : Hash(String, String)) { x += 5 }
+    router.add "plus", &cb
+    router.handle "plus"
+    x.should eq 15
+  end
+
+  it "should handle command with argument" do
+    router = CLI::CommandRouter.new
+    x = 10
+    router.add "plus {x}" do |params|
+      x += params["x"].to_i32
+    end
+    router.handle "plus 5"
+    x.should eq 15
+  end
+
+  it "should handle command with three arguments" do
+    router = CLI::CommandRouter.new
+    x = 0
+    router.add "plus {x} {y} {z}" do |p|
+      x = p["x"].to_i32 + p["y"].to_i32 + p["z"].to_i32
+    end
+    router.handle "plus 1 3 6"
+    x.should eq 10
+  end
 end
diff --git a/src/cli/command_router.cr b/src/cli/command_router.cr
index dc84da8..6f3dd24 100644
--- a/src/cli/command_router.cr
+++ b/src/cli/command_router.cr
@@ -1,17 +1,42 @@
 class CLI::CommandRouter
   def initialize
-    @mappings = [] of {String, Proc(Nil)}
+    @mappings = [] of {Regex, Proc(Hash(String, String), Nil)}
   end
 
-  def add(route, &block)
-    @mappings.push({route, block})
+  def add(route, &block : Hash(String, String) -> Nil)
+    pattern = route_to_regex(route)
+    @mappings.push({pattern, block})
   end
 
   def handle(command)
-    @mappings.each do |i|
-      if i[0] == command
-        i[1].call
-      end
+    @mappings.each do |handler|
+      handle_pattern(command, *handler)
     end
   end
+
+  private def handle_pattern(command, pattern, cb)
+    m = command.match(pattern)
+    return if m.nil?
+    groups = m.named_captures
+    nil_groups = groups.select { |k, v| v.nil? }
+    return if nil_groups.size != 0
+    params = groups.transform_values { |v| v.to_s }
+    cb.call params
+  end
+
+  private def route_to_regex(route) : Regex
+    vals = route.partition(/\{[a-z]+?\}/)
+    param = vals[1].lstrip('{').rstrip('}')
+    result = ""
+    if vals[0] != ""
+      result += Regex.escape(vals[0])
+    end
+    if vals[1] != ""
+      result += sprintf "(?P<%s>.+?)", param
+    end
+    if vals[2] != ""
+      result += route_to_regex(vals[2]).source
+    end
+    Regex.new(result)
+  end
 end