1 files changed, 58 insertions, 0 deletions
diff --git a/src/Var.vala b/src/Var.vala
new file mode 100644
index 0000000..1437ede
--- /dev/null
+++ b/src/Var.vala
@@ -0,0 +1,58 @@
+namespace Eva {
+  public class Var : Object, Term {
+    public string name {get; construct;}
+    
+    public Var(string name0) {
+      assert(name0.get_char() == '_' || name0.get_char().isupper());
+      
+      Object(name: name0);
+    }
+    
+    public string to_string() {
+      return name;
+    }
+    
+    internal static string alias(string key, Gee.Map<string, string> aliases) {
+      if(!(key in aliases))
+        return key;
+      else
+        return alias(aliases[key], aliases);
+    }
+    
+    protected bool do_match(Term o, Gee.Map<string, Term> vars, Gee.Map<string, string> aliases) {
+      string key = alias(name, aliases);
+      
+      if(o is Var) {
+        Var v = o as Var;
+        string vkey = alias(v.name, aliases);
+        
+        if(key == vkey)
+          return true;
+        
+        if(key in vars && vkey in vars)
+          return vars[key].do_match(vars[vkey], vars, aliases);
+        else if(!(vkey in vars)) {
+          aliases[vkey] = key;
+          return true;
+        }
+        else /* !(key in vars) */ {
+          aliases[key] = vkey;
+          return true;
+        }
+      }
+      else {
+        if(key in vars) {
+          return vars[key].do_match(o, vars, aliases);
+        }
+        else {
+          vars[key] = o;
+          return true;
+        }
+      }
+    }
+    
+    public void encode(Erl.Buffer buffer) {
+      assert_not_reached();
+    }
+  }
+}