This project uses the phplrt library to parse .srt files. While phplrt is a very interesting and powerful project, it suffers from imperfect documentation and a lack of examples. Below you can find some information about how both this code and phplrt work.
See development/examples/base-example.php for an example.
| Term | What It Is |
|---|---|
| Lexer | Breaks text into tokens (T_INDEX, T_TEXT, etc.) |
| Parser | Takes tokens, applies grammar rules, builds tree |
| Grammar | Rules that describe valid structure (Block : <T_INDEX>) |
| Compiler | Reads .pp grammar file, produces lexer + parser config |
| AST | Abstract Syntax Tree — the parsed result as objects |
| Builder | Creates AST nodes from matched rules |
| Reducers | PHP code that transforms matched tokens into custom objects |
Input: "1\n00:00:01,111 --> 00:00:02,222\nHello world\n\n"
│
▼
┌────────────────────────────────────────────────────────────────┐
│ LEXER │
│ Breaks into tokens using regex patterns │
│ │
│ %token T_TIMECODE (\d{2})[,.:，．。：](\d{2})[,.:，．。 │
│ %token T_ARROW \h*-->\h* │
│ %token T_INDEX (?<=^)\d+(?=\r?\n) │
└────────────────────────────────────────────────────────────────┘
│
▼
[T_INDEX:"1"] [T_NEWLINE] [T_TIMECODE:"00:00:01,111"]
[T_ARROW] [T_TIMECODE:"00:00:02,222"] [T_NEWLINE]
[T_TEXT:"Hello world"] [T_BLANK]
│
▼
┌────────────────────────────────────────────────────────────────┐
│ PARSER │
│ Matches token sequences against rules │
│ │
│ #Block -> { return SrtBlockNodeFactory::create($children); } │
│ : <T_INDEX> ::T_NEWLINE:: │
│ Timecode() ::T_NEWLINE:: │
│ TextLines() │
│ ::T_BLANK::? │
│ ; │
└────────────────────────────────────────────────────────────────┘
│
▼
┌────────────────────────────────────────────────────────────────┐
│ AST (Abstract Syntax Tree) │
│ │
│ Document {SrtDocumentNode} │
│ └── children {array[N]} │
│ ├── 0 Block {SrtBlockNode} │
│ │ ├── index 1 {int} // T_INDEX │
│ │ ├── startTime 1111 {int} // T_TIMECODE │
│ │ ├── endTime 2222 {int} // T_TIMECODE │
│ │ └── text Hello world {string} // T_TEXT │
│ └── 1 Block ... │
└────────────────────────────────────────────────────────────────┘