# Syntax Nybl's syntax is deliberately simple. If you've seen Python or a C-family language, most of it will look familiar — curly braces for blocks, `//` for comments, newlines (rather than semicolons) terminating statements. ## Blocks Code blocks use curly braces `{ }` and only appear after control-flow or declaration keywords (`if`, `else`, `while`, `for`, `repeat`, `fn`, `struct`, `enum`, `match`): ```nybl if count > 3 { print("That's a lot!") } ``` > **Important:** The opening `{` must be on the same line as its keyword. Nybl automatically inserts semicolons at the end of lines, so putting `{` on the next line would cause a parse error. ```nybl // Good if count > 3 { print("Nice!") } // Bad — will cause an error if count > 3 { print("Nice!") } ``` ## Statements Statements end with a newline. Nybl automatically inserts semicolons after lines ending in: - An identifier or literal - `true`, `false`, `none` - `break`, `continue`, `return` - `)`, `]`, `}` You can put multiple statements on one line with an explicit semicolon: ```nybl let x = 1; let y = 2 ``` ## Comments Line comments start with `//`. Everything after `//` on that line is ignored: ```nybl // This is a comment let x = 5 // So is this ``` There is no block-comment syntax. `#` is **not** a comment leader — a stray `#` produces a lexer error. ## Identifiers Variable and function names start with a letter or underscore and can contain letters, digits, and underscores: ```nybl let my_var = 5 let _count = 0 let item3 = "hello" ``` ### Case conventions are enforced Nybl checks the *shape* of every declared name at parse time and rejects mismatches with a suggestion: | Declaration | Required shape | Examples | |-------------|----------------|----------| | `let`, `fn`, parameters, fields, aliases, `for`-loop vars, match bindings | starts with a lowercase letter or `_` | `let x`, `fn double(n)`, `for i in …` | | `const` | ALL_CAPS (+ digits / `_`) | `const PI = 3.14`, `const MAX_SIZE = 100` | | `struct`, `enum`, variant names | starts with an uppercase letter | `struct Point`, `enum Shape { Circle, Rect }` | Single-letter types like `enum Dir { N, E, S, W }` are fine — the rule is "starts with an uppercase letter", not "must have a lowercase character somewhere." A leading underscore (`_foo`, `_Internal`, `_DEBUG`) marks a name as "private by convention" — glob `use` imports skip them. The wildcard `_` on its own is used in `let _ = foo()` (explicitly ignore) and in patterns (match anything). ## Whitespace Spaces and tabs are insignificant — use whatever indentation style you like. Only newlines matter (they end statements). ## Keywords These words are reserved and can't be used as identifiers: ``` let const pub fn return if else while for in repeat break continue use as struct enum match try true false none ``` There are no word-spelled logical operators — use `&&`, `||`, `!` rather than `and`, `or`, `not`.