+Op

Author: zverok

lib/time_calc.rb

@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
-require_relative 'time_calc/units'
-require_relative 'time_calc/util'
+require_relative 'time_calc/value'
 
 class TimeCalc
   class << self
@@ -10,41 +9,38 @@ class << self
     def now
       new(Time.now)
     end
-  end
 
-  OPERATIONS = %i[+ - floor ceil round].freeze
+    def from(time)
+      Value.new(time)
+    end
 
-  attr_reader :source, :operations
+    def from_now
+      from(Time.now)
+    end
+  end
 
-  def initialize(source)
-    @source = source
+  def initialize(time)
+    @value = Value.new(time)
   end
 
   def inspect
-    '<%s(%p)>' % [self.class, source]
+    '<%s(%p)>' % [self.class, @value.to_time]
   end
 
-  def op(name, span, unit)
-    OPERATIONS.include?(name) or fail ArgumentError, "Unrecognized operation #{name.inspect}"
-    Units.get(unit).public_send(name, source, span)
-  end
+  OPERATIONS = %i[merge truncate floor ceil round + -].freeze
 
   OPERATIONS.each do |name|
-    define_method(name) { |span, unit = nil|
-      # allow +(:year) and +(3, :years) call-sequences
-      # ...and round(:tuesday) instead of round(1/7r, :week)
-      span, unit = guess_span(span) if unit.nil?
-      op(name, span, unit)
-    }
+    define_method(name) { |*args| @value.public_send(name, *args).to_time }
   end
 
-  private
-
-  def guess_span(unit)
-    if (wday = WEEKDAYS.index(unit))
-      [Rational(wday, 7), :weeks]
-    else
-      [1, unit]
+  class << self
+    OPERATIONS.each do |name|
+      define_method(name) { |*args| Op.new([[name, *args]]) }
     end
   end
+
+  # the rest: just delegate
+
 end
+
+require_relative 'time_calc/op'

lib/time_calc/op.rb

@@ -0,0 +1,23 @@
+class TimeCalc
+  class Op
+    def initialize(chain = [])
+      @chain = chain
+    end
+
+    def inspect
+      '<%s %s>' % [self.class, @chain.map { |name, *args| "#{name}(#{args.join(' ')})"}.join('.')]
+    end
+
+    TimeCalc::OPERATIONS.each do |name|
+      define_method(name) { |*args| Op.new([*@chain, [name, *args]]) }
+    end
+
+    def call(time)
+      @chain.reduce(Value.new(time)) { |val, (name, *args)| val.public_send(name, *args) }.to_time
+    end
+
+    def to_proc
+      method(:call).to_proc
+    end
+  end
+end

lib/time_calc/value.rb

@@ -18,7 +18,6 @@ class Value
     }.freeze
     UNITS = %i[year month day hour min sec subsec].freeze
     ALL_UNITS = %i[year month week day hour min sec].freeze
-    CONSTRUCT_UNITS = %i[year month day hour min sec].freeze
     MULTIPLIERS = {
       sec: 1,
       min: 60,
@@ -40,9 +39,10 @@ class Value
 
     def self.from_h(hash, utc_offset: Time.now.utc_offset)
       hash
+        .slice(*UNITS)
         .merge(EMPTY_HASH) { |_k, val, empty| val || empty }
         .tap { |h| h[:sec] += h.delete(:subsec) }
-        .values_at(*CONSTRUCT_UNITS)
+        .values
         .then { |components| Value.new(Time.new(*components, utc_offset)) }
     end