Create macro for constructing a program

src/main.rs

@@ -13,6 +13,13 @@ struct Program {
     funcs: HashMap<char, String>
 }
 
+macro_rules! create_program {
+    ($filename:expr, $prog_name:ident) => {
+        let contents = fs::read_to_string($filename).expect("Something went wrong reading the file");
+        let mut $prog_name = Program::from_string(contents);
+    };
+}
+
 impl Program {
     fn from_string(program: String) -> Program {
         let mut op_list: Vec<String> = Vec::new();
@@ -148,8 +155,7 @@ impl Program {
         let filename = argument_vec[0];
 
         // Read contents of the provided file and construct a symbolic Program from it
-        let contents = fs::read_to_string(filename).expect("Something went wrong reading the file");
-        let mut prog = Program::from_string(contents);
+        create_program!(filename, prog);
         prog.run();
 
         if argument_vec.len() > 1 {
@@ -243,8 +249,7 @@ fn main() {
     let filename = &args[1];
 
     // Read contents of the provided file and construct a symbolic Program from it
-    let contents = fs::read_to_string(filename).expect("Something went wrong reading the file");
-    let mut prog = Program::from_string(contents);
+    create_program!(filename, prog);
     prog.run();
 }
 

src/tests.rs

@@ -1,8 +1,11 @@
 use super::*;
 
-fn make_program(contents: &str) -> Program {
-    Program::from_string(contents.to_string())
+macro_rules! create_program_with_contents {
+    ($contents:expr, $prog_name:ident) => {
+        let mut $prog_name = Program::from_string($contents.to_string());
+    };
 }
+
 #[test]
 fn test_math() {
     assert_eq!(eval::do_math("2-2".to_string(), '+'), 4);
@@ -10,27 +13,31 @@ fn test_math() {
 #[test]
 #[should_panic]
 fn test_undefined_opcode() {
-    make_program("Hello\nWorld!").run();
+    create_program_with_contents!("Hello\nWorld!", prog);
+    prog.run()
 }
 #[test]
 #[should_panic]
 fn test_undefined_variable() {
-    make_program("p$v").run();
+    create_program_with_contents!("p$v", prog);
+    prog.run()
 }
 #[test]
 #[should_panic]
 fn test_undefined_function() {
-    make_program("p*x").run();
+    create_program_with_contents!("p*x", prog);
+    prog.run()
 }
 #[test]
 fn test_factory() {
-    let prog = make_program("lhHello\nlwWorld\np$h $w");
+    create_program_with_contents!("lhHello\nlwWorld\np$h $w", prog);
+    prog.run();
     let vec_to_check: Vec<String> = vec!["lhHello", "lwWorld", "p$h $w"].into_iter().map(|s| s.to_string()).collect();
     assert_eq!(prog.data, vec_to_check);
 }
 #[test]
 fn test_args() {
-    let mut prog = make_program("lhHello\nlwWorld\np$h $w");
+    create_program_with_contents!("lhHello\nlwWorld\np$h $w", prog);
     prog.run();
     let args_to_check: HashMap<char, String> = [('h', String::from("Hello")), ('w', String::from("World"))].iter().cloned().collect();
     assert_eq!(prog.vars, args_to_check);
@@ -38,7 +45,7 @@ fn test_args() {
 
 #[test]
 fn test_funcs() {
-    let mut prog = make_program("fxa10-10\nfys10-5\np*x *y");
+    create_program_with_contents!("fxa10-10\nfys10-5\np*x *y", prog);
     prog.run();
     let funcs_to_check: HashMap<char, String> = [('x', String::from("a10-10")), ('y', String::from("s10-5"))].iter().cloned().collect();
     assert_eq!(prog.funcs, funcs_to_check);