shader-crusher 0.2.0

use std::env;
use std::fs::File;
use std::io::Write;
use std::path::Path;

fn all_combinations( input: &[u8;4], l: u8 ) -> Vec<String> {
	let mut r = Vec::new();
	if l <= 0 {
	} else if l == 1 {
		for i in input {
			r.push( format!( "{}", *i as char).to_string() );
		}
	} else {
		let s = all_combinations( &input, l-1 );
		for e in s {
			r.push( e.clone() );	// :HACK: not true
			for i in input {
				r.push( format!( "{}{}", e, *i as char).to_string() );
			}
		}
	}
	r
}
fn main() {
    let out_dir = env::var("OUT_DIR").unwrap();
    let dest_path = Path::new(&out_dir).join("glsl_keywords.rs");
    let mut f = File::create(&dest_path).unwrap();

    f.write_all(b"
    	pub struct GlslKeywords {
    	}

    	impl GlslKeywords {
        	pub fn get() -> std::vec::Vec<String> {
        		let mut r = Vec::new();
        		r.push(\"main\".to_string());	// technically not a keyword according to the spec, but we get in trouble if we 'fix' it, so blacklist it here
    \n").unwrap();

    // blacklist all swizzles, accroding to the glsl spec mixing components from different sets is not legal
    // :TODO: would be better if we could recognize a swizzle during parsing
    for e in all_combinations( b"xywz", 4 ) {
    	f.write_fmt( format_args!("\t\t\t\tr.push(\"{}\".to_string());\n", e )).unwrap();
    }
    for e in all_combinations( b"rgba", 4 ) {
    	f.write_fmt( format_args!("\t\t\t\tr.push(\"{}\".to_string());\n", e )).unwrap();
    }
    for e in all_combinations( b"stpq", 4 ) {
    	f.write_fmt( format_args!("\t\t\t\tr.push(\"{}\".to_string());\n", e )).unwrap();
    }

    let ks = include_str!("src/glsl_keywords.txt");
    for k in ks.split_whitespace() {
    	f.write_fmt( format_args!("\t\t\t\tr.push(\"{}\".to_string());\n", k) ).unwrap();
    }
    f.write_all(b"
    			r
        	}
    	}
    ").unwrap();

    println!("cargo:rerun-if-changed=src/glsl_keywords.txt");
}