From 364857d964c8bdcd47171201b64d422c0317aa9a Mon Sep 17 00:00:00 2001
From: Jorge Luis Martinez Gomez <jol@jol.dev>
Date: Thu, 24 Sep 2020 22:44:00 -0700
Subject: [PATCH] add more argument options to char_in

---
 README.md                 |  5 ++++-
 lib/parsby/combinators.rb | 27 ++++++++++++++++++++++++---
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index 865b3a9..c3f4afc 100644
--- a/README.md
+++ b/README.md
@@ -103,9 +103,12 @@ between(lit("<"), lit(">"), decimal).parse "<100>"
   lit("foo").fmap {|x| x.upcase }.parse "foo"
   #=> "FOO"
 
-  # Parse a character from the choices in a string
+  # Parse a character from the choices in a set of strings or ranges
   char_in(" \t\r\n").parse "\t"
   #=> "\t"
+  typical_identifier_characters = ['a'..'z', 'A'..'Z', 0..9, "_"]
+  join(many(char_in("!?", typical_identifier_characters))).parse "foo23? bar"
+  #=> "foo23?"
 
   # Make parser optional
   group(optional(lit("foo")), lit("bar")).parse "bar"
diff --git a/lib/parsby/combinators.rb b/lib/parsby/combinators.rb
index 9d28b63..5e9c59b 100644
--- a/lib/parsby/combinators.rb
+++ b/lib/parsby/combinators.rb
@@ -185,12 +185,33 @@ def splicer
       Parsby::Splicer
     end
 
-    # Parses a single char from those contained in the string argument.
-    define_combinator :char_in do |s|
+    # Accepts any number of strings or ranges optionally arbitrarily nested
+    # in arrays and parses a single char from the char options in the
+    # resulting joined string.
+    #
+    #   join(many(char_in('a'..'z', 0..9))).parse "foo23 bar"
+    #   #=> "foo23"
+    #
+    #   char_options = ['a'..'z', "!@#$%^"]
+    #   join(many(char_in(0..9, char_options))).parse "foo23!@ bar"
+    #   #=> "foo23!@"
+    #
+    define_combinator :char_in do |*strings|
+      string = strings
+        .flatten
+        .map do |s|
+          if s.is_a?(Range)
+            s.to_a.join
+          else
+            s
+          end
+        end
+        .join
+
       ~splicer.start do
         Parsby.new do |c|
           char = any_char.parse c
-          unless s.chars.include? char
+          unless string.chars.include? char
             raise ExpectationFailed.new c
           end
           char