Rio Programming Language

Goal

A safe, tiny, flexible, systemsy, data-friendly, functional-first language, with no runtime nor std lib of its own.

See also my YouTube channel called Context Free where I discuss programming languages, including things I think about while working on Rio.

Description

NOTE: These examples are out of date. I've been redoing things on other branches. Maybe I'll merge back to main someday.

For an example, here's a Rio script:

use "c"

do
  # Assignment here declares new *const* values
  name = "Alice"
  age = 40
  show_prices([
    # Shorthand field names work like JS or Rust
    {age, name},
    {name = "Bernie", age = 14},
    {name = "Clara", age = 9},
    {name = "Darlene", age = 68},
  ])
end do

Person struct
  name: string
  age: int
end

show_prices proc(persons: [Person])
  for person in persons
    printf("%s pays $%.2f\n", person.name, ticket_price(person.age))
  end
end

ticket_price proc(age: int): float
  if
    case age <= 11
      6.75
    end
    case age >= 62
      7.00
    end
    else
      if age < 18
        printf("You think age %d gets child prices here?\n", age)
      end
      11.00
    end
  end if
end ticket_price

That compiles to this C file (with manual whitespace added to the struct array in main for readability):

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>

typedef double rio_float;
typedef ptrdiff_t rio_int;
typedef const char* rio_string;

// sample2.rio

typedef struct sample2_Person {
  rio_string name;
  rio_int age;
} sample2_Person;

typedef struct rio_Span_sample2_Person {
  sample2_Person* items;
  rio_int len;
} rio_Span_sample2_Person;

void sample2_show_prices(rio_Span_sample2_Person const persons);
rio_float sample2_ticket_price(rio_int const age);

int main() {
  rio_string const name = "Alice";
  rio_int const age = 40;
  sample2_show_prices((rio_Span_sample2_Person){(sample2_Person[4]){
    (sample2_Person){.age = age, .name = name},
    (sample2_Person){.name = "Bernie", .age = 14},
    (sample2_Person){.name = "Clara", .age = 9},
    (sample2_Person){.name = "Darlene", .age = 68}
  }, 4});
}

void sample2_show_prices(rio_Span_sample2_Person const persons) {
  {
    rio_Span_sample2_Person rio_span = persons;
    for (rio_int rio_index = 0; rio_index < rio_span.len; rio_index += 1) {
      sample2_Person person = rio_span.items[rio_index];
      printf("%s pays $%.2f\n", person.name, sample2_ticket_price(person.age));
    }
  }
}

rio_float sample2_ticket_price(rio_int const age) {
  if (age <= 11) {
    return 6.75;
  }
  else if (age >= 62) {
    return 7.00;
  }
  else {
    if (age < 18) {
      printf("You think age %d gets child prices here?\n", age)
    }
    return 11.00;
  }
}

Status

A few things work (like the example above!).
Many other things don't yet.
No error checking at all yet.
Supports relative path module includes (for combining multiple files) and uses (for separate modules).
Coding ground up with language server in mind.
Uses arenas, interning, and so on with the hopes of being efficient.
Coded in C++ for now but without the C++ std lib for faster compiling and fewer dependencies later down the road.
Current strategy: Support enough features I can port the compiler to Rio, then port, then finish and polish.
Testing output in tcc, since high speed compilation is great. (And testing in gcc, too.)

tjpalmer/rio

Rio Programming Language

Goal

Description

Status