feat: implement identifier matching system

src/dartfile.rs

@@ -88,7 +88,7 @@ impl DotfileRaw {
 /// The configuration object parsed from the `config` field in `dartgun.toml`
 #[derive(Debug)]
 pub struct Machine {
-    identifiers: Vec<String>,
+    pub identifiers: Vec<String>,
 }
 
 impl Machine {

src/dartgun.rs

@@ -1,17 +1,25 @@
 /// Utilities for translating Dartfiles into actual actions on the system.
 use crate::dartfile::{Dartfile, Dotfile};
-use std::os::unix::fs::symlink;
+use std::{collections::HashSet, os::unix::fs::symlink};
+
+fn have_common_elements(vec1: &[String], vec2: &[String]) -> bool {
+    let set: HashSet<_> = vec1.iter().collect();
+    vec2.iter().any(|item| set.contains(item))
+}
 
 impl Dotfile {
-    pub fn create_symlink(&self) -> Result<(), std::io::Error> {
-        symlink(self.location.canonicalize()?, &self.destination)
+    pub fn create_symlink(&self, machine_identifiers: &[String]) -> Result<(), std::io::Error> {
+        if have_common_elements(&self.identifiers, machine_identifiers) {
+            return symlink(self.location.canonicalize()?, &self.destination);
+        }
+        Ok(())
     }
 }
 
 impl Dartfile {
     pub fn create_symlinks(&self) -> Result<(), std::io::Error> {
         for dot in self.dots.iter() {
-            dot.create_symlink()?
+            dot.create_symlink(&self.machine.identifiers)?
         }
         Ok(())
     }