diff --git a/README.md b/README.md index 5a59a87..f9f918c 100644 --- a/README.md +++ b/README.md @@ -178,6 +178,37 @@ The `examples/` directory contains several `.tralla` files demonstrating various * `fibonacci.tralla`: Demonstrates loops and function calls (note the return value limitation). * `string_manipulation.tralla`: Shows string concatenation. +## Implementation Details (For Developers) + +This section provides a brief overview of how the Tralalero_lang interpreter is structured and some of the design choices and challenges encountered during its development. + +### Interpreter Core + +The interpreter is implemented in `src/main.rs` as a single-pass, line-by-line parser and executor. It reads the `.tralla` file content, splits it into lines, and then processes each line sequentially. + +### Parsing Strategy + +* **Line-by-Line Processing:** The interpreter reads and executes code one line at a time. +* **Comment Stripping:** Before processing, each line is checked for `//` (single-line comments), and any content after `//` is removed. +* **Whitespace Splitting:** Commands and arguments are primarily parsed by splitting the line by whitespace. This simplicity leads to some of the known limitations, particularly with string literals containing spaces. +* **Semicolon Trimming:** Trailing semicolons (`;`) are trimmed from expressions and variable names during parsing to ensure correct value retrieval and storage. + +### Variable Handling + +Variables are stored in a `HashMap`, where the key is the variable name and the value is its string representation. Numeric values are converted to strings before storage and parsed back to `f64` when used in arithmetic operations or comparisons. + +### Arithmetic and Expression Evaluation + +* **`let` Keyword:** The `let` keyword handles both direct variable assignments (e.g., `let x = 10;`) and simple binary arithmetic expressions (e.g., `let sum = a + b;`). +* **`get_value` Function:** This helper function attempts to parse a given string as an `f64` literal. If it fails, it checks if the string corresponds to a variable name and, if so, attempts to parse the variable's string value as an `f64`. +* **Limited Expression Parsing:** The current arithmetic parsing within `let` is limited to `operand operator operand`. More complex expressions require a more sophisticated parsing algorithm (e.g., shunting-yard or abstract syntax tree generation), which is not yet implemented. + +### Function Call Mechanism + +* **Function Definition (`Lirili Larila`):** Functions are stored with their name, argument list, and the start/end program counter (PC) lines of their body. +* **Function Call (`Trippi Troppi`):** When a function is called, a new local scope (a cloned `HashMap` of variables) is created. Arguments are passed by value into this local scope. The interpreter then executes the lines within the function's body. +* **No Return Value Propagation:** A significant current limitation is that functions do not return values to the calling scope. Any `return` statements within a function only terminate its execution; the value is not captured or made available to the caller. This means functions primarily serve for side effects (e.g., printing). + ## Development Tralalero_lang is an ongoing project. Contributions and suggestions are welcome! @@ -188,4 +219,4 @@ Tralalero_lang is an ongoing project. Contributions and suggestions are welcome! * Add support for more complex mathematical expressions. * Introduce more data types (e.g., booleans, lists). * Improve error handling and reporting. -* Add more built-in functions (e.g., string manipulation, type conversion). +* Add more built-in functions (e.g., string manipulation, type conversion). \ No newline at end of file