doc: More doc

Author: DanSnow

src/binary_parser/macros/array.cr

@@ -1,4 +1,27 @@
 class BinaryParser
+
+  # Declare an array field
+  #
+  # ### Argument:
+  # - name: Field name
+  # - opt: Options
+  #   - `:type`: Element type, must implement `from_io`
+  #   - `:count`: Element size, can be a number for fixed size, or a symbol for variable size
+  #
+  # ### Example:
+  # ```crystal
+  # # Fixed size
+  # class Parser < BinaryParser
+  #   array :arr, { type: UInt8, count: 10 } # Array of 10 UInt8
+  # end
+  #
+  # # Variable size
+  # class Parser < BinaryParser
+  #   uint32 :size
+  #   array :arr, { type: UInt8, count: :size }
+  # end
+  # ```
+  #
   macro array(name, opt)
     {% raise "Must have count and type" unless opt[:type] && opt[:count]  %}
     property! :{{name.id}}

src/binary_parser/macros/string.cr

@@ -1,4 +1,26 @@
 class BinaryParser
+
+  # Declare a string field
+  #
+  # ### Argument:
+  # - name: Field name
+  # - opt: Options
+  #   - `:count`: Sting length, can be a number for fixed size, `-1` for zero terminated, or a symbol for variable size
+  #
+  # ### Example:
+  # ```crystal
+  # # Fixed size
+  # class Parser < BinaryParser
+  #   string :str, { count: 10 } # Array of 10 UInt8
+  # end
+  #
+  # # Variable size
+  # class Parser < BinaryParser
+  #   uint32 :size
+  #   string :str, { count: :size }
+  # end
+  # ```
+  #
   macro string(name, opt = { count: -1 })
     property! :{{name.id}}
     @{{name.id}} = ""

src/binary_parser/macros/type.cr

@@ -1,4 +1,23 @@
 class BinaryParser
+
+  # Nested BinaryParser
+  #
+  # ### Argument:
+  # - name: Field name
+  # - klass: Another BinaryParser
+  #
+  # ### Example:
+  # ```crystal
+  #
+  # class InnerParser < BinaryParser
+  #   uint8 :foo
+  # end
+  #
+  # class Parser < BinaryParser
+  #   type :inner, InnerParser
+  # end
+  # ```
+  #
   macro type(name, klass)
     property! :{{name.id}}
     @{{name.id}} = {{klass}}.new