Chapter 2: Milestone 1, a better C

Rome wasn't build in a day.

To make a language as ambitious and complex as Venus, we need a very solid base. As what we want to achieve is a better D, which is a better C++, which is an enhanced C, we need to look back and start with C first. So we need a better C first.

C is a much simpler language compared to C++ or D, so we can attack it with more ease and strengthen our understanding of the compiler in the process. We won't do OO or high-level compile time magic here. But C has its warts and can be narly, like macros, which I'm not inclined to implement. So we won't write the exact C language, instead, we'll design a language that has similar complexity to C, but should look simpler in most cases.

Here is what I want to get in the first Milestone:

• function definition and calling
• basic builtin types including int, double and char
• basic control flows including if-else, while, for and switch
• module and import instead of textual inclusion
• basic static-if and/or version blocks to replace text macros in C
• immutability first, variables second
• able to call extern C functions

Here is what M1 would look like:

// comment
import std.io // module and import

// extern C function/constant declaration
extern sin(arg double) double
extern PI

// define a new function
fun toRadian(degree int) double {
    return degree*PI/180
}

// main block
main {
    // value definition and assignment
    val degree = 30

    // variable definition
    var result

    // assignment with a function call
    result = sin(toRadian(degree))

    // call println function in std.io module
    println("sin(30°)=", result)

}