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--- tanszek:oktatas:techcomm:yaml [2025/11/03 20:34] – created knehez
+++ tanszek:oktatas:techcomm:yaml [2025/11/17 20:35] (current) – [Summary] knehez
@@ Line 60: / Line 60: @@
 ===== Data Types =====
-  * Strings, numbers, booleans, lists, and mappings (dictionaries)
-  * Multi-line strings are supported using `|` (literal) or `>` (folded):
+YAML supports a range of basic and complex data types.
+Values can be written in **implicit** or **explicit** form — YAML automatically detects the type from context, but types can also be specified manually using tags (e.g., `!!str`, `!!int`).
+==== 1. Scalars ====
+Scalars are single values such as strings, numbers, or booleans.
+^ Type | Example | Notes |
+| String | `name: "Alice"` | Quotation marks are optional unless special characters are used. |
+| Integer | `age: 25` | No quotes needed; negative values allowed. |
+| Float | `price: 19.99` | Decimal notation or scientific form (`1.2e+3`) supported. |
+| Boolean | `enabled: true` or `enabled: no` | `true/false`, `yes/no`, and `on/off` are equivalent. |
+| Null | `value: null` or `value: ~` | Both mean “no value”. |
+| Date/Time | `created: 2025-11-03` | ISO 8601 format is recommended. |
+Explicit typing (less common but useful for validation):
 <code yaml>
-description: |
+id: !!int "42"
-  This text
+flag: !!bool "yes"
-  spans multiple
+pi: !!float "3.14159"
-  lines.
+text: !!str 1234   # forced as string, not number
 </code>
+==== 2. Strings ====
+YAML offers flexible ways to define strings:
+  * **Plain style:** `title: Hello World`
+  * **Single-quoted:** `path: 'C:\Users\Name'`
+    (backslashes are preserved literally)
+  * **Double-quoted:** `message: "Line1\nLine2"`
+    (supports escape sequences like `\n`, `\t`)
+  * **Multi-line literal (`|`):** preserves line breaks
+    <code yaml>
+    description: |
+      This is line one.
+      This is line two.
+    </code>
+  * **Folded block (`>`):** joins lines into a single paragraph
+    <code yaml>
+    note: >
+      This sentence
+      continues on the next line.
+    </code>
+==== 3. Collections ====
+YAML supports two structured types: **sequences (lists)** and **mappings (dictionaries)**.
+  * **Sequences:** ordered lists of elements, marked with `-`
+    <code yaml>
+    colors:
+      - red
+      - green
+      - blue
+    </code>
+  * **Mappings:** unordered key–value pairs
+    <code yaml>
+    person:
+      name: Bob
+      age: 30
+      city: London
+    </code>
+  * **Inline form:** lists and dictionaries can also be written on one line
+    <code yaml>
+    colors: [red, green, blue]
+    person: {name: Bob, age: 30}
+    </code>
+==== 4. Nested Structures ====
+Lists and mappings can be combined to represent complex hierarchical data:
+<code yaml>
+students:
+  - name: Anna
+    grades: [A, B, A]
+  - name: Mark
+    grades:
+      - B
+      - C
+      - A
+</code>
+==== 5. Aliases and Anchors ====
+YAML allows referencing the same data in multiple places using **anchors (&)** and **aliases (*)**.
+<code yaml>
+defaults: &base
+  host: localhost
+  port: 8080
+development:
+  <<: *base
+  debug: true
+release:
+  <<: *base
+  debug: false
+</code>
+This feature reduces duplication and keeps configuration files consistent.
+==== 6. Summary ====
+  * YAML automatically infers most types but supports explicit typing.
+  * Scalars, sequences, and mappings cover all standard data models.
+  * Multi-line and folded strings improve readability.
+  * Anchors and aliases allow reuse of data blocks.
 ===== Validation and Schema =====
@@ Line 90: / Line 192: @@
 </code>
-===== Educational Demo Idea =====
-Show the same configuration both in JSON and YAML, and ask:
-  * Which one is easier to read?
-  * What are the risks of using indentation as syntax?
-  * How does the structure represent a **syntax tree**?
 ===== Summary =====
@@ Line 100: / Line 198: @@
   * It was created to bridge the gap between human readability and machine processing.
   * It plays a central role in modern **DevOps**, **configuration management**, and **data description languages**.
+----
+===== JSON & YAML Exercises =====
+==== 1. Identify the format & fix errors ====
+**Task:**
+Determine whether the snippet is in JSON or YAML format. If invalid, fix it.
+<code>
+name: ChatGPT
+skills: ["nlp", "reasoning", "qa"]
+version: "5.1"
+</code>
+**Solution:**
+This is valid YAML.
+==== 2. Convert JSON → YAML ====
+**Task:**
+<code json>
+{
+  "user": "John",
+  "role": "student",
+  "active": true,
+  "points": 128
+}
+</code>
+**Solution (YAML):**
+<code yaml>
+user: John
+role: student
+active: true
+points: 128
+</code>
+==== 3. Convert YAML → JSON ====
+**Task:**
+<code yaml>
+server:
+  host: localhost
+  port: 8080
+  logging: true
+</code>
+**Solution (JSON):**
+<code json>
+{
+  "server": {
+    "host": "localhost",
+    "port": 8080,
+    "logging": true
+  }
+}
+</code>
+==== 4. Extend the YAML configuration ====
+**Task:**
+Add an 'admins' list (min. 2 names) and an 'ssl' setting.
+<code yaml>
+webserver:
+  host: 192.168.1.20
+  port: 3000
+</code>
+**Solution:**
+<code yaml>
+webserver:
+  host: 192.168.1.20
+  port: 3000
+  ssl: true
+  admins:
+    - alice
+    - bob
+</code>
+==== 5. Valid or invalid JSON? Fix it. ====
+**Task:**
+<code json>
+{
+  "name": "Test app":
+  "version": 1.0,
+  "debug": true,
+}
+</code>
+**Solution:**
+Errors: misplaced colon, trailing comma.
+Correct version:
+<code json>
+{
+  "name": "Test app",
+  "version": 1.0,
+  "debug": true
+}
+</code>
+==== 6. Fix the indentation errors (YAML) ====
+**Task:**
+<code yaml>
+database:
+    name: testdb
+      port: 5432
+  host: localhost
+</code>
+**Solution:**
+<code yaml>
+database:
+  name: testdb
+  port: 5432
+  host: localhost
+</code>
+==== 7. Create the JSON structure ====
+**Task:**
+Create this structure in JSON:
+  * application
+    * name: "ProdApp"
+    * database:
+      * host: "10.0.0.12"
+      * port: 3306
+      * users: ["admin", "guest"]
+**Solution:**
+<code json>
+{
+  "application": {
+    "name": "ProdApp",
+    "database": {
+      "host": "10.0.0.12",
+      "port": 3306,
+      "users": ["admin", "guest"]
+    }
+  }
+}
+</code>
+==== 8. Rewrite "sizes" as a list ====
+**Task:**
+<code yaml>
+product:
+  name: hoodie
+  sizes: "S, M, L, XL"
+</code>
+**Solution:**
+<code yaml>
+product:
+  name: hoodie
+  sizes:
+    - S
+    - M
+    - L
+    - XL
+</code>
+==== 9. Create your own configuration ====
+**Task:**
+Create a configuration (YAML or JSON) including:
+  * server settings
+  * 3 users
+  * roles
+  * features list (3 items)
+**Solution (YAML example):**
+<code yaml>
+app:
+  server:
+    host: 0.0.0.0
+    port: 5000
+  users:
+    - name: anna
+      role: admin
+    - name: bela
+      role: editor
+    - name: koris
+      role: read-only
+  features:
+    - analytics
+    - backup
+    - notifications
+</code>
+==== 10. List differences between JSON and YAML ====
+**Task:**
+List 5 differences.
+**Solution:**
+  * YAML uses indentation instead of curly braces.
+  * YAML supports comments (#), JSON does not.
+  * JSON has stricter syntax; YAML is more flexible.
+  * YAML supports advanced features (anchors, aliases).
+  * JSON keys must be strings; YAML keys do not require quotes.
+==== 11. Industrial config conversion ====
+**Task:** Convert to YAML and add `backup: true`.
+<code json>
+{
+  "plant": "Factory_A",
+  "machines": [
+    {"id": 1, "type": "CNC", "status": "online"},
+    {"id": 2, "type": "Laser", "status": "offline"}
+  ],
+  "schedule": {
+    "shift": "night",
+    "workers": 12
+  }
+}
+</code>
+**Solution:**
+<code yaml>
+plant: Factory_A
+machines:
+  - id: 1
+    type: CNC
+    status: online
+  - id: 2
+    type: Laser
+    status: offline
+schedule:
+  shift: night
+  workers: 12
+backup: true
+</code>
+==== 12. Convert string booleans to real booleans ====
+**Task:**
+<code yaml>
+config:
+  verbose: "true"
+  auto_restart: "false"
+  safe_mode: "False"
+</code>
+**Solution:**
+<code yaml>
+config:
+  verbose: true
+  auto_restart: false
+  safe_mode: false
+</code>