Expression Macros

An expression macro is a type of expression which is resolved during assembly. This is useful for defining constant values or constant functions on values, such as defining getters on memory pointers.

Defining an Expression Macro

Expression macros can accept an arbitrary number of parameters. Parameters are referenced within the macro definition by prepending $ to the parameter's name.

#![allow(unused)]
fn main() {
extern crate etk_asm;
let src = r#"
%def my_macro()
    42
%end

%def sum(x, y, z)
    $x+$y+$z
%end
"#;
let mut ingest = etk_asm::ingest::Ingest::new(Vec::new());
ingest.ingest(file!(), src).unwrap();
}

Using an Expression Macro

Expression macros can be invoked anywhere an expression is expected.

#![allow(unused)]
fn main() {
extern crate etk_asm;
let src = r#"
%def my_macro()
   42
%end
%def sum(x, y, z)
    $x+$y+$z
%end
push1 my_macro()
push1 sum(1, 2, my_macro())
"#;
let mut output = Vec::new();
let mut ingest = etk_asm::ingest::Ingest::new(&mut output);
ingest.ingest(file!(), src).unwrap();
assert_eq!(output, &[0x60, 0x2a, 0x60, 0x2d]);
}