overview.md

Overview

Main Features

1. Import a module: queue = import("/core/std/queue") (you can also import from external sources like GitHub).
2. Primitive types: int, float, char, string,byte, bool, error, type, nothing.
3. Bindings: my_var:int = 19 (type is optional, everything is immutable).
4. Sequence: my_array = [1, 2, 3] (type of my_array is [int] which means a sequence of integers).
5. HashMap: my_map = ["A":1, "B":2, "C":3] (type of my_map is [string:int], which is a map of string to integer)
6. Named type: MyInt = int (Defines a new type MyInt with same binary representation as int).
7. Type alias: IntType : int (A different name for the same type).
8. Struct type: Point = struct{x: int, y:int, data: float} (Like C struct).
9. Struct literal: location = Point{x:10, y:20, data:1.19}.
10. Union type: MaybeInt = int | nothing (Can store either of two types, note that this is a named type).
11. Function: calculate = fn(x:int, y:int -> float) { x/y } (Functions are all lambdas, the last expression in the body is return value).
12. Concurrency: my_data := processData(x,y,z) (Start a new micro-thread and evaluate an expression in parallel).
13. Generic Types: ValueKeeper = fn(T: type -> type) { struct{data: T} } (Generic types are represented using functions that returns a type)
14. Generic Functions: push = fn(x: T, stack: Stack(T), T: type -> Stack(T)) { ... }
15. Enum: Weekdays = enum [monday, tuesday, wednesday, thursday, friday]
16. Errors: result = validateData(a,b,c)@{makeError(InvalidArgument)}(If call to validateData returns an error, then evaluate the expression inside brackets and return the result immediately).

Symbols

1. # Comment
2. . Access struct members (customer.name)
3. () Function declaration and call (process(customer))
4. {} Code block, multiple selections from module namespace, error check, struct declaration and literals
5. [] Sequence and hashMap (data=map["CA"])
6. | Union data type (x:int|float|string)
7. -> Function declaration (process = fn(...->...))
8. // Nothing-check operator (result=a//b evaluates to a if it is not nothing,else b)
9. : Type declaration (binding, struct field and function inputs), type alias, struct literal (x:int)
10. = Binding declaration, named type (x=12)
11. _ Place-holder (lambda creator and assignment) (partial = process(customer,_,_)
12. :: Function call composition (result = id :: findCustomer :: printCustomer)
13. @ Error check (data = process@)
14. ? If operator (x=data==10 ? "A" if data is 10, then x will be "A" otherwise nothing)
15. & Type inference for struct literals (When type can be inferred from context: &{x:0,y:20})
16. := Parallel execution
17. .. Access inside module (data = module1..func1(1,2,3))

Reserved Keywords

Primitive data types: int, float, char, byte, bool, string, nothing, type,error

Logical Operators: and, or, not

Data type identifiers: fn, struct, enum

Reserved identifiers: true, false, import

Coding Style

1. Use 4 spaces indentation.
2. You must put each statement on a separate line. Newline is the statement separator.
3. Naming: SomeDataType, someFunction, some_data_binding, some_module_alias.
4. If a function returns a type (generic types) it should be named like a type.
5. If a binding is a reference to a function, it should be named like a function.
6. You can use 0x prefix for hexadecimal numbers and 0b for binary.
7. You can use _ as digit separator in number literals.

Operators

Operators are mostly similar to C language:

• Conditional operators: and, or, not, ==, !=, >=, <=

• Arithmetic: +, -, *, /, %, %%, >>, <<, **

• Note that == will do a comparison based on contents of its operands.

• A // B will evaluate to A if it is not nothing, else it will be evaluated to B (e.g. y = x // y // z // 0).

• A ? B will evaluate boolean expression A first, if true will evaluate to B, otherwise will evaluate to nothing. This can be mixed with // to provide ifElse construct.

• Example: home_dir = (is_root ? "/root") // (is_default_user ? "/default") // (is_unknown ? "unknown") // "/tmp"

• Conditional operators return true or false which are equal to 1 and 0 respectively when used as index of a sequence.

• Comments can appear anywhere in the code and start with #. Anything after # till end of the line is comment.

• Meta comments start with ## as first two characters of the line and can be defined for a binding, type or function. These will be scanned with tools to automatically generate documentation. If ## is the only thing in the line, it starts a block comment until another ## appears in the file.

    ## 
    some docs about this function
    x:int - comments about this input
    -> string - comments about the output
    ##
    process = fn(x:int -> string) { ... }
  
    ##Meta comment in one line
    x = 12
  
    ## 
    some docs about this type
    x:int - comments about this field
    y: string - comments about the y
    ##
    DataTypeX = struct {x:int, y:string}