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Language Guide

Language Tour & Specification

Comprehensive tour of NextViper language concepts, syntax rules, and type rules.

NextViper Language Specification (v1.0.0 Apex)

Status: Official Stable Specification

Version: 1.0.0

Target Execution Engines: Tree-Walk Interpreter, Stack Bytecode Virtual Machine, Native LLVM/C Backend

Syntax & Lexical Structure

1.1 Source Encoding & Identifiers

Source files MUST be encoded in valid UTF-8.

Keywords and identifiers are case-sensitive.

Identifiers begin with an ASCII letter [a-zA-Z] or underscore _, followed by letters, digits [0-9], or underscores.

1.2 Comments

Single-line comments start with // and extend to the end of the line.

Multi-line comments start with /* and end with */. Multi-line comments can be arbitrarily nested.

1.3 Blocks and Delimiters

NextViper uses Python/Nim-inspired colon : syntax followed by statements or blocks.

Braces { ... } are also accepted for C-family interoperability.

Statement termination is newline or semicolon ;.

Variables & Scoping

2.1 Variable Declaration

Variables are introduced with let:

main.nv

let x = 10
let name: string = "NextViper"
let mut counter = 0

Variable re-assignment modifies existing bindings in lexical scope.

Lexical scoping: Inner blocks shadow outer bindings without destroying outer bindings.

Data Types & Type System

3.1 Primitives

int: 64-bit signed two's complement integer (int64_t).

float: 64-bit IEEE 754 floating-point (double).

bool: Boolean true or false.

string: Immutable UTF-8 byte sequence.

nil / null: Unit null value.

3.2 Collections

list[T]: Dynamically resizable array of values.

map[string, T]: Associative hash table with string keys.

3.3 Scientific & AI Types

Tensor: Multi-dimensional dense floating-point numerical tensor.

DataFrame: Tabular structured series and columns.

3.4 Gradual Type Inference

Static type annotations are checked at compile/check time:

main.nv

fn multiply(a: int, b: int) -> int:
    return a * b

Expressions & Operators

4.1 Operator Precedence Table (Highest to Lowest)

Precedence	Operators	Description	Associativity
1 (Highest)	`.` `()` `[]`	Member access, function call, index	Left
2	`!` `-` `~`	Logical NOT, Unary negation, Bitwise NOT	Right
3	`**`	Exponentiation	Right
4	`*` `/` `%`	Multiplication, Division, Modulo	Left
5	`+` `-`	Addition, Subtraction, String Concat	Left
6	`..` `..=`	Half-open and Inclusive Ranges	Left
7	`<` `<=` `>` `>=`	Relational Comparisons	Left
8	`==` `!=`	Equality and Inequality	Left
9	`&&` `and`	Logical AND	Left
10	`		` `or`	Logical OR	Left
11	`	>`	Pipeline Operator	Left
12 (Lowest)	`=` `+=` `-=` `*=` `/=`	Assignment operators	Right

Control Flow

5.1 Conditional Statements

main.nv

if condition:
    // branch 1
elif other_condition:
    // branch 2
else:
    // fallback

5.2 Loop Statements

main.nv

// Range loop
for i in 0..10:
    print(i)

// Collection iteration
for item in collection:
    print(item)

// While loop
while condition:
    if break_needed:
        break
    if skip_needed:
        continue

Functions, Lambdas & Closures

6.1 Function Declarations

main.nv

fn add(a, b):
    return a + b

// Arrow expression syntax
fn double(x): x * 2

// Typed signature
fn divide(a: float, b: float) -> float:
    return a / b

6.2 First-Class Lambdas & Closures

main.nv

let add_five = fn(x): x + 5
let values = [1, 2, 3].map(fn(x): x * 10)

Modules & Ecosystem

Modules use explicit export and import semantics.

Relative imports (import "./utils.nv" as utils) are canonicalized and path-isolated.

Package manifests are stored in nextviper.json.