Sugu Language

Overview

Sugu は学習目的で開発されたシンプルなインタプリタ言語です。 JavaScript に似た構文を持ち、Go で実装されています。

Quick Start

# ビルド
go build -o sugu .

# REPL を起動
./sugu

# ファイルを実行
./sugu examples/hello.sugu

Hello World

outln("Hello, Sugu!");

Features

Variables

mut x = 10;       // 再代入可能
const PI = 3.14;  // 再代入不可

x = 20;           // OK
PI = 3;           // Error!

Data Types

Type	Example
number	`42`, `3.14`
string	`"hello"`
boolean	`true`, `false`
null	`null`
array	`[1, 2, 3]`
map	`{"key": "value"}`

Functions

func add(a, b) => {
    return a + b;
}

outln(add(1, 2));  // 3

Control Flow

// if-else
if (x > 0) {
    outln("positive");
} else {
    outln("non-positive");
}

// while
mut i = 0;
while (i < 5) {
    outln(i);
    i = i + 1;
}

// for (with ++ and +=)
for (mut i = 0; i < 5; i++) {
    outln(i);
}

// for-in (array)
for (item in [1, 2, 3]) {
    outln(item);
}

// for-in with index
for (i, item in ["a", "b", "c"]) {
    outln(string(i) + ": " + item);
}

// for-in (map)
for (key, value in {"x": 1, "y": 2}) {
    outln(key + " = " + string(value));
}

// switch
switch (x) {
    case 1: { outln("one"); }
    case 2: { outln("two"); }
    default: { outln("other"); }
}

// try-catch
try {
    throw "error";
} catch (e) {
    outln(e);
}

Operators

Category	Operators
Arithmetic	`+`, `-`, `*`, `/`, `%`
Postfix	`++`, `--`
Compound Assignment	`+=`, `-=`, `*=`, `/=`, `%=`
Comparison	`==`, `!=`, `<`, `>`, `<=`, `>=`
Logical	`&&`, `\\|\\|`, `!`

Builtin Functions

I/O

Function	Description
`out(x)`	Print without newline
`outln(x)`	Print with newline
`in()`	Read user input

Type & Length

Function	Description
`type(x)`	Get type of value
`len(x)`	Get length of string/array/map

Type Conversion

Function	Description
`int(x)`	Convert to integer (truncate toward zero)
`float(x)`	Convert to float
`string(x)`	Convert to string
`bool(x)`	Convert to boolean

Array

Function	Description
`push(arr, x)`	Append to array (returns new array)
`pop(arr)`	Remove last element (returns new array)
`first(arr)`	Get first element
`last(arr)`	Get last element
`rest(arr)`	Get all but first element
`contains(arr, x)`	Check if element exists in array/string
`concat(a, b, ...)`	Concatenate multiple arrays

Map

Function	Description
`keys(map)`	Get map keys as array
`values(map)`	Get map values as array
`delete(map, key)`	Delete key from map

String

Function	Description
`split(str, sep)`	Split string by separator
`join(arr, sep)`	Join array elements with separator
`trim(str)`	Remove leading/trailing whitespace
`replace(str, old, new)`	Replace all occurrences
`substring(str, start, end)`	Get substring (rune-based)
`indexOf(str, substr)`	Find substring position (rune-based)
`toUpper(str)`	Convert to uppercase
`toLower(str)`	Convert to lowercase

Math

Function	Description
`abs(x)`	Absolute value
`floor(x)`	Round toward negative infinity
`ceil(x)`	Round toward positive infinity
`round(x)`	Round to nearest integer
`sqrt(x)`	Square root
`pow(x, y)`	Power (x^y)
`min(a, b, ...)`	Minimum value
`max(a, b, ...)`	Maximum value
`random()`	Random number [0, 1)

File I/O

Function	Description
`readFile(path)`	Read file contents
`writeFile(path, content)`	Write to file
`appendFile(path, content)`	Append to file
`fileExists(path)`	Check if file exists

Comments

// Single line comment

//--
Multi-line
comment
--//

AWS Lambda

Sugu は AWS Lambda 上で実行できます。詳細は AWS Lambda での Sugu 実行を参照。

Documentation

Language Specification - 言語仕様
Backlog - 将来の改善予定
AWS Lambda Usage - AWS Lambda での実行方法

Architecture

sugu/
├── token/      # Token definitions
├── lexer/      # Lexical analysis
├── ast/        # Abstract Syntax Tree
├── parser/     # Parsing
├── object/     # Object system
├── evaluator/  # Evaluation
├── repl/       # REPL
└── lambda/     # AWS Lambda runtime

License

MIT

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