From 659bd8b797d341500fffd3bb681d99278e38bf3c Mon Sep 17 00:00:00 2001
From: Michael Housh <mhoush@houshhomeenergy.com>
Date: Fri, 31 Jan 2025 20:34:00 -0500
Subject: [PATCH] feat: Working, unless it ends with a list, however using
 terminator isn't working at the moment.

---
 Sources/main.swift | 181 +++++++++++++++------------------------------
 1 file changed, 59 insertions(+), 122 deletions(-)

diff --git a/Sources/main.swift b/Sources/main.swift
index d63cfc9..6a462ad 100644
--- a/Sources/main.swift
+++ b/Sources/main.swift
@@ -2,7 +2,6 @@ import Foundation
 @preconcurrency import Parsing
 
 let yamlString = """
----
 author: Michael Housh
 categories:
   - HVAC
@@ -14,130 +13,20 @@ date: 2023-10-21
 lastmod: 2023-10-21
 image: banner.png
 featuredImage: banner.png
-series:
-  - General
 tags:
   - HVAC
   - General
   - Programming
-
----
+title: "You Should Learn Markdown"
 """
 
 _ = """
+series:
+  - General
 title: "You Should Learn Markdown"
 slug: "you-should-learn-markdown"
 """
 
-enum YamlItem {
-  case boolean(Bool)
-  case date(year: Int, month: Int, day: Int)
-  case string(String)
-  case listItem(String)
-
-  private static let dateParser = Parse(input: Substring.UTF8View.self) {
-    Digits(4)
-    "-".utf8
-    Digits(2)
-    "-".utf8
-    Digits(2)
-  }.map { Self.date(year: $0.0, month: $0.1, day: $0.2) }
-
-  private static let booleanParser = Parse(input: Substring.UTF8View.self) {
-    Bool.parser()
-  }.map { Self.boolean($0) }
-
-  private static let quotedString = Parse(input: Substring.UTF8View.self) {
-    "\"".utf8
-    PrefixUpTo("\"".utf8)
-    "\"".utf8
-  }
-
-  private static let stringParser = Parse(input: Substring.UTF8View.self) {
-    OneOf {
-      quotedString
-      Rest()
-    }
-  }.map { Self.string(String(Substring($0))) }
-
-  private static let listItemParser = Parse(input: Substring.UTF8View.self) {
-    Skip { Whitespace() }
-    "- ".utf8
-    Rest()
-  }.map { Self.listItem(String(Substring($0))) }
-
-  static let parser = OneOf {
-    dateParser
-    booleanParser
-    listItemParser
-    stringParser
-  }
-}
-
-let yamlBlockParser = Parse(input: Substring.UTF8View.self) {
-  "---\n".utf8
-  Many {
-    PrefixUpTo(":".utf8)
-    ":".utf8
-    Optionally { YamlItem.parser }
-    // PrefixUpTo("\n".utf8)
-    // From(.substring) { YamlLine.parser }
-  } separator: {
-    "\n".utf8
-  } terminator: {
-    // "\n".utf8
-    "---".utf8
-  }
-}
-
-let stringLine = #"author: "Michael Housh""#
-// let parsedLine = try yamlLineParser.parse(stringLine[...].utf8)
-// print(parsedLine)
-
-let stringItem = "foo"
-let quotedItem = "\"foo\""
-let dateItem = "2025-01-29"
-let boolItem = "true"
-
-try print(YamlItem.parser.parse(stringItem[...]))
-try print(YamlItem.parser.parse(quotedItem[...]))
-try print(YamlItem.parser.parse(dateItem[...]))
-try print(YamlItem.parser.parse(boolItem[...]))
-
-let kvLine = "author: Michael Housh"
-var listLine = #"""
-  - HVAC
-  - General
-  - Programming
-
-"""#[...]
-
-struct YamlList: Parser {
-
-  var body: some Parser<Substring.UTF8View, [String]> {
-    Many(into: [String]()) { array, string in
-      array.append(string)
-    } element: {
-      Whitespace()
-      "-".utf8
-      Whitespace()
-      PrefixUpTo("\n".utf8).map(.string)
-      "\n".utf8
-    }
-  }
-}
-
-try print(YamlList().parse(listLine))
-
-var yamlLines = """
-author: Michael Housh
-test:
-  - HVAC
-  - General
-  - Programming
-
-"""[...]
-
 struct SimpleYamlValue: Parser {
   enum Output: Equatable {
     case array([String])
@@ -169,17 +58,47 @@ struct SimpleYamlValue: Parser {
   }
 }
 
-// This works, but doesn't handle lists well.
 struct SimpleYamlParser: Parser {
-  var body: some Parser<Substring.UTF8View, [String: SimpleYamlValue.Output]> {
-    Many(into: [String: SimpleYamlValue.Output]()) { (dict: inout [String: SimpleYamlValue.Output], pair: (String, SimpleYamlValue.Output)) in
+
+  typealias Output = [String: SimpleYamlValue.Output]
+
+  var body: some Parser<Substring.UTF8View, Output> {
+    Many(into: Output()) { (dict: inout Output, pair: (String, SimpleYamlValue.Output)) in
       let (key, value) = pair
       dict[key] = value
     } element: {
-      PrefixUpTo(":".utf8).map(.string)
-      ":".utf8
-      Whitespace()
-      SimpleYamlValue()
+      // Parses a key and array.
+      OneOf {
+        Parse {
+          PrefixUpTo(":".utf8).map(.string)
+          ":\n".utf8
+          Many(into: [String]()) { array, string in
+            array.append(string)
+          } element: {
+            From(.substring) { Whitespace() }
+            "-".utf8
+            From(.substring) { Whitespace() }
+            PrefixUpTo("\n".utf8).map(.string)
+          } separator: {
+            "\n".utf8
+          }
+          // terminator: {
+          //   OneOf {
+          //     Peek { PrefixUpTo(":".utf8) }
+          //     End()
+          //   }
+          // }
+        }
+        .map { ($0.0, SimpleYamlValue.Output.array($0.1)) }
+
+        // Parse a key and a single value.
+        Parse {
+          PrefixUpTo(":".utf8).map(.string)
+          ":".utf8
+          Whitespace()
+          SimpleYamlValue()
+        }
+      }
     } separator: {
       "\n".utf8
     } terminator: {
@@ -196,13 +115,31 @@ date: 2023-10-21
 lastmod: 2023-10-21
 image: banner.png
 featuredImage: banner.png
+test:
+  - HVAC
+  - General
+  - Programming
+foo: Bar
 """#
 
+var keyedList = """
+test:
+  - HVAC
+  - General
+  - Programming
+foo: Bar
+"""[...].utf8
+
+// let parsedList = try keyedListParser.parse(&keyedList)
+// print(parsedList)
+
 let parsed = try SimpleYamlParser().parse(simpleYamlString[...].utf8)
-// print(parsed)
+// let parsed = try SimpleYamlParser().parse(yamlString[...].utf8)
 
 for (key, value) in parsed {
   print("\(key): \(value)")
 }
 
+// assert(parsed.keys.count == 10)
+
 // try print(SimpleYamlParser().parse(simpleYamlString[...].utf8))