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--- tanszek:oktatas:techcomm:yaml [2025/11/03 20:34] – created knehez
+++ tanszek:oktatas:techcomm:yaml [2025/11/03 20:39] (current) – [Data Types] 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
+</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 =====