Language.md

Language showcase

Here is a small showcase with explanation of each language feauter like:

• variables
• blocks
• ifs
• loops
• functions Example programs can be found in (this folder)[/examples]

Supported types

• strings
• booleans
• numbers (all numbers are treated as f64)
• nil

Example

// booleans
var b1 = true;
var b2 = false;

// strings
var s1 = "string example";

// numbers
var n1 = 2;
var n2 = 2.3;

// nil
var n = nil;

---

Print

print is a built in special keyword that allows user to print to standard output

• can be parsed only as a statement

Pattern

print <expression>;

Example

print "Hello, world!";

---

Arithmetics

mathematical and boolean expressions are supported.

Supported math operators: +, -, *, /

Supported boolean operators: and, or

Supported comparision operators: ==, !=, <, >, <=, >=

Also language support two main unary operators: -, !

Examples

1 + 2 * 3 // evaluates to `7.0`

3 * 4 < 15 // evaluates to `true`

!(1 < 2) // evaluates to `false`

Var

lets user to declare variables

• can be parsed only as a statement

Pattern

var <ident> = <expression>;

var <ident>; // here the value is `nil`

Example

var test = "test string";

---

Block

lets user to define scoped set of statements

• can be parsed as statement or expression
• last non statement value is parsed as return expression

Pattern

{ <set_of_statements> <return_expression> }

return_expression is optional here if the block ends with an expression it becomes its return value. It also works fo fn blocks if the funtion does not return early it returns the default block return value so either the last expression or nil

Example

{
    var test = "test string";
}
var block_value = {
    1 + 2 + 3
};

---

If

• can be parsed as statement or expression
• its block can have return value
• returns value of a block
• can have else statement

Pattern

if(<condition_expression>) <yes_block> else <no_block>

yes and no expressions should be blocks, else is completly optional

if we use if as expression and else block is not present it will return nil in else case

Example

if (1 < 2) { print "yes"; }

var if_value = if (1 < 2) {
    1
} else {
    2
};

---

For & While loops

• can be parsed as statement or expression
• its block cant have return value
• can return value by break <expression>;
• can be stopped with break;
• can be continued with continue
• returns nil by default

Pattern

for(<init_statement>;<condition_expression>;<step_statement>) <loop_block>

while(<condition_expression>) <loop_block>

Example

for(var i = 1; i < 3; i = i + 1) {
    print i;
}

var for_val = for(var i = 1; i < 3; i = i + 1) {
    if (i == 2) {
        break i;
    }
};

if we want for loop to return value we can use break with epxression right after it, otherwise for loop will return nil

Fn

TBD