a few more consts

ml.cpp

@@ -152,7 +152,7 @@ class Error {
 public:
     // Create an error with the value that caused the error,
     // the scope where the error was found, and the message.
-    Error(Value v, Environment const &env, const char *msg);
+    Error(const Value &v, Environment const &env, const char *msg);
     // Copy constructor is needed to prevent double frees
     Error(Error const &other);
     ~Error();
@@ -183,7 +183,7 @@ public:
     // Constructs a floating point value
     Value(double f) : type(FLOAT) { stack_data.f = f; }
     // Constructs a list
-    Value(std::vector<Value> list) : type(LIST), list(list) {}
+    Value(const std::vector<Value> &list) : type(LIST), list(list) {}
 
     // Construct a quoted value
     static Value quote(Value quoted) {
@@ -197,7 +197,7 @@ public:
     }
 
     // Construct an atom
-    static Value atom(std::string s) {
+    static Value atom(const std::string &s) {
         Value result;
         result.type = ATOM;
 
@@ -207,7 +207,7 @@ public:
     }
 
     // Construct a string
-    static Value string(std::string s) {
+    static Value string(const std::string &s) {
         Value result;
         result.type = STRING;
 
@@ -217,7 +217,7 @@ public:
     }
 
     // Construct a lambda function
-    Value(std::vector<Value> params, Value ret, Environment const &env) : type(LAMBDA) {
+    Value(const std::vector<Value> &params, Value ret, Environment const &env) : type(LAMBDA) {
         // We store the params and the result in the list member
         // instead of having dedicated members. This is to save memory.
         list.push_back(Value(params));
@@ -233,7 +233,7 @@ public:
     }
 
     // Construct a builtin function
-    Value(std::string name, Builtin b) : type(BUILTIN) {
+    Value(const std::string &name, Builtin b) : type(BUILTIN) {
         // Store the name of the builtin function in the str member
         // to save memory, and use the builtin function slot in the union
         // to store the function pointer.
@@ -773,7 +773,7 @@ private:
     Environment lambda_scope;
 };
 
-Error::Error(Value v, Environment const &env, const char *msg) : env(env), msg(msg) {
+Error::Error(const Value &v, Environment const &env, const char *msg) : env(env), msg(msg) {
     cause = new Value;
     *cause = v;
 }
@@ -1014,7 +1014,7 @@ std::vector<Value> parse(std::string s) {
 }
 
 // Execute code in an environment
-Value run(std::string code, Environment &env) {
+Value run(const std::string &code, Environment &env) {
     // Parse the code
     std::vector<Value> parsed = parse(code);
     // Iterate over the expressions and evaluate them