CLI Reference

The `kem` CLI

The kem command-line tool is the only binary you need. It runs files, starts a REPL, formats code, and lets you inspect the token stream and AST.

kem --help

KemLang - A Gujarati-flavored programming language

Usage: kem [COMMAND]

Commands:
  run      Run a KemLang file
  repl     Start an interactive REPL
  fmt      Format KemLang files
  tokens   Show the token stream for a file
  ast      Show the Abstract Syntax Tree for a file
  version  Show version information

Options:
  --help   Show this message and exit

kem run

Execute a .jsk file. This is the main command you'll use.

$kem run hello.jsk

Run a file

kem cho, Sanket!

Flags

flagdescription

--tracePrint the token stream and AST before running the program - useful for debugging

--helpShow usage information for this command

Running with trace

The --trace flag is invaluable when a program isn't behaving as expected - it shows you exactly how the interpreter sees your code.

$kem run hello.jsk --trace

Run with token + AST output

Tokens:
  KEM_BHAI        'kem bhai'       1:0
  BHAI_BOL        'bhai bol'       2:2
  STRING          '"kem cho!"'     2:10
  AAVJO_BHAI      'aavjo bhai'     3:0

AST:
Program
└── Print
    └── Literal: "kem cho!"

kem cho!

File extensions

kemlang-py files use the .jsk extension. If you pass a file with a different extension,kem run will print a warning but still execute it.

kem repl

Start an interactive Read-Eval-Print Loop. Type kemlang-py code and press Ctrl+D (Unix) or Ctrl+Z (Windows) to execute.

$kem repl

Start interactive REPL

KemLang REPL v0.1.3
Type your code and press Ctrl+D (Unix) or Ctrl+Z (Windows) to execute.

>>> aa x che 10
    bhai bol x * 2
[Ctrl+D]
20

>>>

The REPL automatically wraps your input in kem bhai / aavjo bhai if you don't include them - so you can skip the boilerplate when experimenting.

kem fmt

Format a .jsk file in-place, or check whether files are already formatted.

$kem fmt hello.jsk

Format a file in place

Formatted hello.jsk

$kem fmt .

Format all .jsk files in current directory

Formatted examples/hello.jsk
Formatted examples/loop_and_if.jsk
Already formatted examples/errors.jsk

Check mode

Use --check to verify formatting without modifying files - useful in CI or pre-commit hooks.

$kem fmt --check .

Check without modifying

Would format examples/hello.jsk
1 file(s) need formatting

Exit code: 1

What the formatter does

›Normalises indentation to 2 spaces inside blocks
›Adds spaces around binary operators (a+b → a + b)
›Adds spaces around comparison operators
›Removes trailing whitespace
›Ensures a single newline at end of file

kem tokens

Print the token stream produced by the lexer. Useful for understanding how kemlang-py reads your source code, and for debugging lexer issues.

$kem tokens hello.jsk

Show lexer token stream

Tokens for hello.jsk:
  KEM_BHAI        'kem bhai'       1:0
  BHAI_BOL        'bhai bol'       2:2
  STRING          '"kem cho!"'     2:10
  AAVJO_BHAI      'aavjo bhai'     3:0
  EOF             ''               4:0

Each token shows: type, literal value, and line:column position in the source file.

Token types

token typewhat it represents

KEM_BHAIkem bhai - program start

AAVJO_BHAIaavjo bhai - program end

BHAI_BOLbhai bol - print keyword

AAaa - variable declaration keyword

CHEche - assignment keyword

JOjo - if keyword

NAHI_TOnahi to - else keyword

FARVUfarvu - loop body keyword

JYA_SUDHIjya sudhi - loop condition keyword

TAME_JAOtame jao - break

AAGAL_VADOaagal vado - continue

BHAI_CHHEbhai chhe / true

BHAI_NATHIbhai nathi / false

STRINGa string literal

INTEGERan integer literal

FLOATa decimal literal

IDENTIFIERa variable name

EOFend of file

kem ast

Pretty-print the Abstract Syntax Tree that the parser builds from your source. Useful for understanding how kemlang-py parsed your program.


jsk
kem bhai
  aa x che 10
  jo x > 5 {
    bhai bol "big"
  }
aavjo bhai

$kem ast example.jsk

Show the parsed AST

AST for example.jsk:
Program
├── Declaration (x)
│   └── Literal: 10
└── If
    ├── Condition: Binary (>)
    │   ├── Left: Variable (x)
    │   └── Right: Literal: 5
    └── Then:
        └── Print
            └── Literal: "big"

kem version

Print the installed version of kemlang-py.

$kem version

Show version

KemLang 0.1.3

Exit codes

All kem commands follow standard exit code conventions:

codemeaning

0Success - program ran without errors

1Error - lexer, parser, or runtime error occurred

2Usage error - wrong command or missing argument

Use exit codes in shell scripts to check whether a program succeeded:


bash
kem run my_program.jsk && echo "Success" || echo "Failed"

← Examples Error reference

The kem CLI