Correct typos

Author: jmettraux

README.md

@@ -29,7 +29,7 @@ module Fun include Raabro
 
   def pstart(i); rex(nil, i, /\(\s*/); end
   def pend(i); rex(nil, i, /\)\s*/); end
-    # parenthese start and end, including trailing white space
+    # parentheses start and end, including trailing white space
 
   def comma(i); rex(nil, i, /,\s*/); end
     # a comma, including trailing white space
@@ -246,7 +246,7 @@ One can reparse with `error: true` and receive an error array with the parse err
 ```ruby
 err = Sample::Fun.parse('f(a, b', error: true)
   # yields:
-  # [ line, column, offest, error_message, error_visual ]
+  # [ line, column, offset, error_message, error_visual ]
 [ 1, 4, 3, 'parsing failed .../:exp/:fun/:arg', "f(a, b\n   ^---" ]
 ```
 

doc/test.rb

@@ -16,7 +16,7 @@ module Fun include Raabro
 
   def pstart(i); rex(nil, i, /\(\s*/); end
   def pend(i); rex(nil, i, /\)\s*/); end
-    # parenthese start and end, including trailing white space
+    # parentheses start and end, including trailing white space
 
   def comma(i); rex(nil, i, /,\s*/); end
     # a comma, including trailing white space

lib/raabro.rb

@@ -265,7 +265,7 @@ def rex(name, input, regex_or_string)
     def _quantify(parser)
 
       return nil if parser.is_a?(Symbol) && respond_to?(parser)
-        # so that :plus and co can be overriden
+        # so that :plus and co can be overridden
 
       case parser
       when '?', :q, :qmark then [ 0, 1 ]

spec/spec_helper.rb

@@ -63,9 +63,9 @@ def plus(i); rex(:plus, i, /\+\s*/); end
   def minus(i); rex(:minus, i, /-\s*/); end
 
   def addition(i); seq(:addition, i, :number, :plus, :op_or_num); end
-  def substraction(i); seq(:substraction, i, :number, :minus, :op_or_num); end
+  def subtraction(i); seq(:subtraction, i, :number, :minus, :op_or_num); end
 
-  def op_or_num(i); alt(nil, i, :addition, :substraction, :number); end
+  def op_or_num(i); alt(nil, i, :addition, :subtraction, :number); end
 end