Small functional language inspired by haskell and rust, made as a fun side project.

Usage

To execute a lambda program simply run

python3 main.py file.lmd

if the file depends on other files you need to add them to the list of sources

python3 main.py file1.lmd file2.lmd

Interpreter searches for the main function and executes it.

Syntax

name start = lowercase | uppercase | "_" | "'" ;
name continue = name start | decimal digit ;

number = 
    decimal digit+
    "0b", binary digit+ |
    "0o", octal digit+ |
    "0x", hex digit+ | 
    decimal digit+, ".", decimal digit+ ;

literal = number | string ;

line comment = "--", any* ;
block comment = "{-", any*, "-}" ;
whitespace = ( " " | "\t" | "\n" )* ;
identifier = name start, name continue* ;
type = uppercase, name continue* ;

qualified identifier = (type, (".", type)*)?, identifier ;
qualified type = type, (".", type)* ;

math symbol = "+" | "-" | "*" | "/" | "%" | "&" | "|" | "^" | "~" ;
comparison symbol = "<" | "=" | ">" ;
misc symbol = "$" | "." ;
operator = (math symbol | comparison symbol | misc symbol)+ -"." ;


program = statement* ;
statement = use | mod | const ;

use = "use", qualified type ;
mod = "mod", type, "{", statement*, "}" ;

const = "pub"?, "const", identifier+, "=" expr ;
expr = term+, (operator, term+)* ;
term = 
    qualified identifier |
    literal |
    if expr |
    fn expr |
    parenthesised expr ;

if expr = "if", expr, "then", expr, "else", expr ;
fn expr = "fn", identifier+, "=>" expr ;
parenthesised expr = "(", expr, ")" ;

Modules

To allow encapsulation and avoid name collisions lambda has modules, defined by keyword mod. Every const declaration can be defined public to be visible when using this module with the use keyword.

Everything (including modules) is contained in the Main module. Each module can see only contents contained in it, unless explicitly uses another module.

mhorod/lambda

Usage

Syntax

Modules