fortran_descriptor_parser

fortran_descriptor_parser provides a macro descriptor_parser to generate a parser at compile time to parse bytes which are formatted according to a fortran format edit descriptor. The macro uses a simplified syntax inspired by the format used in the fortran descriptors.

Syntax

nTw
n = number of repetitions
T = the type to parse (I: i32, S: String, F: f32, D: f64)
w = number of bytes to take

Basic example

use fortran_descriptor_parser::descriptor_parser;
let input = " -0.31415D+01";
let f = descriptor_parser!("D13")(input.as_bytes()).unwrap();
assert_eq!(f, -3.1415);

Explained example

use fortran_descriptor_parser::descriptor_parser;
// input is a string generated by a fortran program.
// For this example a format edit descriptor like the following has been used:
// FORMAT(I10, A10, E13.5, D13.5) and values 1, "Test", -3.1415, 3.1415
let input = "         1      Test -0.31415E+01  0.31415D+01";
// The descriptor_parser macro generates four parsers in a tuple
// bytes 0..10 get parsed into an i32
// bytes 10..20 get parsed into a String
// bytes 20..33 get parsed into a f32
// bytes 33..46 get parsed into a f64
let (i, s, f, d) = descriptor_parser!("I10,S10,F13,D13")(input.as_bytes()).unwrap();
assert_eq!(i, 1);
assert_eq!(s, "Test");
assert_eq!(f, -3.1415);
assert_eq!(d, 3.1415);

Repetitions

use fortran_descriptor_parser::descriptor_parser;
// repetition of single elements can be done like this
descriptor_parser!("3I10");
// which is equivalent to
descriptor_parser!("I10,I10,I10");
// repetition of multiple elements is also supported
descriptor_parser!("2(I5,S5)");
// which is equivalent to
descriptor_parser!("I5,S5,I5,S5");

The macro can parse i32, f32, f64 and Strings