refactoring to get middle/center, possibly more

lib/squib/args/box.rb

@@ -1,17 +1,20 @@
 require_relative 'arg_loader'
+require_relative 'xywh_shorthands'
 
 module Squib::Args
 
   module_function def extract_box(opts, deck, dsl_method_defaults = {})
-    Box.new(deck, dsl_method_defaults).extract!(opts, deck)
+    Box.new(deck, dsl_method_defaults, opts).extract!(opts, deck)
   end
 
   class Box
     include ArgLoader
+    include XYWHShorthands
 
-    def initialize(deck = nil, dsl_method_defaults = {})
+    def initialize(deck = nil, dsl_method_defaults = {}, opts = {})
       @deck = deck
       @dsl_method_defaults = dsl_method_defaults
+      @opts = opts # e.g. value of x can depend on the value of width
     end
 
     def self.parameters
@@ -29,16 +32,22 @@ module Squib::Args
       parameters.keys # all of them
     end
 
+    def validate_x(arg, i)
+      apply_x_shorthands(arg, @deck.width)
+    end
+
+    def validate_y(arg,_i)
+      apply_y_shorthands(arg, @deck.height)
+    end
+
     def validate_width(arg, _i)
       return arg if @deck.nil?
-      return @deck.width if arg == :deck
-      arg
+      apply_x_shorthands(arg, @deck.width)
     end
 
     def validate_height(arg, _i)
       return arg if @deck.nil?
-      return @deck.height if arg == :deck
-      arg
+      apply_y_shorthands(arg, @deck.height)
     end
 
     def validate_x_radius(arg, i)
@@ -49,7 +58,7 @@ module Squib::Args
     def validate_y_radius(arg, i)
       return radius[i] unless radius[i].nil?
       arg
-    end
+    end   
 
   end
 

lib/squib/args/unit_conversion.rb

@@ -13,6 +13,8 @@ module Squib
           arg.rstrip[0..-2].to_f * dpi * INCHES_IN_CM
         when /mm$/ # ends with "mm"
           arg.rstrip[0..-2].to_f * dpi * INCHES_IN_CM / 10.0
+        when /deg$/ # ends with "deg"
+          arg.rstrip[0..-3].to_f * (Math::PI / 180.0)
         else
           arg
         end

lib/squib/args/xywh_shorthands.rb

@@ -0,0 +1,35 @@
+module Squib
+  module Args
+    module XYWHShorthands
+
+      def apply_x_shorthands(arg, deck_width)
+        arg_s = arg.to_s
+        case arg_s
+        when 'middle'
+          deck_width / 2.0
+        when 'center'
+          deck_width / 2.0
+        when 'deck'
+          deck_width
+        else 
+          arg
+        end
+      end
+
+      def apply_y_shorthands(arg, deck_height)
+        arg_s = arg.to_s
+        case arg_s
+        when 'middle'
+          deck_height / 2.0
+        when 'center'
+          deck_height / 2.0
+        when 'deck'
+          deck_height
+        else 
+          arg
+        end
+      end
+
+    end
+  end
+end

lib/squib/dsl/units.rb

@@ -23,5 +23,10 @@ module Squib
       @dpi * Squib::INCHES_IN_CM * n.to_f / 10.0
     end
 
+    # DSL method. See http://squib.readthedocs.io
+    def deg(n)
+      n.to_f * (Math::PI / 180.0)
+    end
+
   end
 end

lib/squib/layout_parser.rb

@@ -1,9 +1,11 @@
 require 'yaml'
+require_relative 'args/xywh_shorthands'
 
 module Squib
   # Internal class for handling layouts
   # @api private
   class LayoutParser
+    include Args::XYWHShorthands
 
     def initialize(dpi = 300)
       @dpi = dpi
@@ -67,6 +69,9 @@ module Squib
     end
 
     def handle_relative_operators(parent_val, child_val)
+      unless has_digits?(parent_val) && has_digits?(child_val)
+        raise "Layout parse error: can't combine #{parent_val} and #{child_val}"
+      end
       if child_val.to_s.strip.start_with?('+=')
         add_parent_child(parent_val, child_val)
       elsif child_val.to_s.strip.start_with?('-=')
@@ -104,6 +109,13 @@ module Squib
       parent_pixels / child_float
     end
 
+    # For relative operators, it's difficult for us to handle 
+    # some of the shorthands - so let's just freak out if you're trying to use 
+    # relative operators with words, e.g. "middle += 0.5in"
+    def has_digits?(str)
+      str.match? /.*\d.*/
+    end
+
     # Does this layout entry have an extends field?
     # i.e. is it a base-case or will it need recursion?
     # :nodoc: