From 8ad9b4b0a05ae9aa080ff8ca1b02db9c94251dea Mon Sep 17 00:00:00 2001
From: Matthew Hall <hallmatthew314@gmail.com>
Date: Sun, 2 Apr 2023 23:59:21 +1200
Subject: Finish final code for walkthrough

---
 README.md | 42 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 37 insertions(+), 5 deletions(-)

(limited to 'README.md')

diff --git a/README.md b/README.md
index 243c3de..b532ea2 100644
--- a/README.md
+++ b/README.md
@@ -99,20 +99,52 @@ Another way to do this is to use `Parser#recover`, which allows a default value
 ```
 # `#map_const` is like `#map`, but it takes a single value to replace
 # the parser value with unconditionally.
-sign = Parser.token('-').map_const(-1_i32).recover(1_i32)
+sign = Parser.token('-')
+  .map_const(-1_i32)
+  .recover(1_i32)
 ```
 
 Final code:
 
+TODO: add to practical tests
+
 ```
-d = Parser(Char, Char).satisfy(&.number?)
-abs_num = d.some.map { |ds| ds.join.to_i32 }
+d = Parser(Char, Char).satisfy(&.number?).named("digit")
+abs_num = d.some.map { |ds| ds.join.to_i32 }.named("abs_num")
 
-sign = Parser.token('-').map_const(-1_i32).recover(1_i32)
+sign = Parser.token('-').map_const(-1_i32).recover(1_i32).named("sign")
 
 int32 = parser_chain Char, Int32, "int32",
   {s, sign},
   {n, abs_num},
-  finally: Parser.pure(n * s)
+  pure: n * s
+
+ws = Parser(Char, Char).satisfy(&.whitespace?)
+  .many
+  .named("whitespace")
+
+arrow = (ws >> Parser.token_sequence("=>".chars) >> ws).named("arrow")
+
+pair = parser_chain Char, {Int32, Int32}, "pair",
+  {x, int32},
+  {_, sep},
+  {y, int32},
+  pure: {x, y}
+
+delim = (ws >> Parser.token(',') >> ws).named("delim")
+
+elements = parser_chain Char, Array({Int32, Int32}), "elements",
+  {pairs, pair.sep_by(delim)},
+  {_,     delim.optional}, # trailing comma
+  pure: pairs
+
+hash_start = (Parser.token('{') >> ws).named("start")
+hash_end   = (ws >> Parser.token('}')).named("end")
+
+hash = parser_chain Char, Hash(Int32, Int32), "hash",
+  {_,  hash_start},
+  {es, elements.recover([] of {Int32, Int32})}
+  {_,  hash_end},
+  pure: es.to_h
 ```
 
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