Added equals

Author: Tko1

src/environment.rs

@@ -1,6 +1,6 @@
 use crate::clojure_std;
 use crate::clojure_string;
-use crate::namespace::{Namespace, Namespaces};
+use crate::namespace::{Namespaces};
 use crate::repl::Repl;
 use crate::rust_core;
 use crate::symbol::Symbol;
@@ -231,6 +231,7 @@ impl Environment {
         let if_macro = Value::IfMacro {};
         let environment = Rc::new(Environment::new_main_environment());
 
+        let equals_fn = rust_core::EqualsFn {};
         let eval_fn = rust_core::EvalFn::new(Rc::clone(&environment));
         let ns_macro = rust_core::NsMacro::new(Rc::clone(&environment));
         let load_file_fn = rust_core::LoadFileFn::new(Rc::clone(&environment));
@@ -388,6 +389,7 @@ impl Environment {
         );
         environment.insert(Symbol::intern("read-line"), read_line_fn.to_rc_value());
 
+        environment.insert(Symbol::intern("="),equals_fn.to_rc_value());
         //
         // Read in clojure.core
         //

src/rust_core.rs

@@ -66,3 +66,6 @@ pub use self::slurp::*;
 
 pub(crate) mod load_file;
 pub use self::load_file::*;
+
+pub(crate) mod equals;
+pub use self::equals::*;

src/rust_core/equals.rs

@@ -0,0 +1,69 @@
+use crate::ifn::IFn;
+use crate::value::{ToValue, Value};
+use std::rc::Rc;
+
+/// (assoc map key val & kvs)
+///
+// General assoc fn; however,  currently just implemented
+// for our one map type, PersistentListMap
+#[derive(Debug, Clone)]
+pub struct EqualsFn {}
+impl ToValue for EqualsFn {
+    fn to_value(&self) -> Value {
+        Value::IFn(Rc::new(self.clone()))
+    }
+}
+impl IFn for EqualsFn {
+    fn invoke(&self, args: Vec<Rc<Value>>) -> Value {
+        if args.is_empty() {
+            //@TODO use proper error function 
+            return Value::Condition(format!(
+                "Wrong number of arguments given to function (Given: {}, Expected: > 0)",
+                args.len()
+            ));
+        }
+
+        for pair in args.windows(2) {
+            let a = &pair[0];
+            let b = &pair[1];
+            if a != b {
+                return Value::Boolean(false);
+            }
+        };
+        Value::Boolean(true)
+
+    }
+}
+
+mod tests {
+    use crate::value::{Value,ToValue};
+    use crate::rust_core::EqualsFn;
+    use crate::keyword::Keyword;
+    use crate::ifn::IFn;
+
+    // Just checks that different Values do not count as equal, and that
+    // at least one Value of the same kind does, and that one Value of the same
+    // kind and different Value doesn't
+    //
+    // Otherwise, does not test every type 
+    #[test]
+    fn equals_basic() {
+        let equals = EqualsFn{};
+        let _i32 = Value::I32(1).to_rc_value();
+        // To test that we're not getting some sort of 'memory equality'
+        let i32_copy = Value::I32(1).to_rc_value();
+        assert!(equals.invoke(vec![i32_copy.clone(),_i32.clone()]).is_truthy());
+        assert!(equals.invoke(vec![_i32.clone(),_i32.clone()]).is_truthy());
+
+        let i32_2 = Value::I32(5).to_rc_value();
+        assert!(!equals.invoke(vec![_i32.clone(),i32_2.clone()]).is_truthy());
+        
+        let keyword = Keyword::intern("cat").to_rc_value();
+        let keyword2 = Keyword::intern("cat").to_rc_value();
+        let keyword3 = Keyword::intern("dog").to_rc_value();
+
+        assert!(equals.invoke(vec![keyword.clone(),keyword2.clone()]).is_truthy());
+        assert!(!equals.invoke(vec![keyword2,keyword3]).is_truthy());
+        assert!(!equals.invoke(vec![keyword,_i32]).is_truthy());
+    }
+}

src/rust_core/flush_stdout.rs

@@ -1,12 +1,11 @@
 use crate::ifn::IFn;
-use crate::value::{Value, ToValue, Evaluable};
+use crate::value::{Value, ToValue};
 use std::rc::Rc;
 
 use std::io;
 
 use crate::error_message;
-use nom::lib::std::convert::TryFrom;
-use std::io::{Read, Write};
+use std::io::{Write};
 
 /// Read a line from stdin TODO: should be aware of *in*
 /// (defn read-line [])
@@ -25,4 +24,4 @@ impl IFn for FlushStdoutFn {
         io::stdout().flush();
         Value::Nil
     }
-}
+}

src/rust_core/read_line.rs

@@ -1,12 +1,11 @@
 use crate::ifn::IFn;
-use crate::value::{Value, ToValue, Evaluable};
+use crate::value::{Value, ToValue};
 use std::rc::Rc;
 
 use std::io;
 
 use crate::error_message;
 use nom::lib::std::convert::TryFrom;
-use std::io::{Read, Write};
 
 /// Read a line from stdin TODO: should be aware of *in*
 /// (defn read-line [])
@@ -31,4 +30,4 @@ impl IFn for ReadLineFn {
             Err(error) => error_message::generic_err(Box::try_from(error).unwrap())
         }
     }
-}
+}

src/value.rs

@@ -530,7 +530,10 @@ impl Value {
     ////////////////////////////////////////////////////////////////////////////////////////////////////
     // Eval Helper
     ////////////////////////////////////////////////////////////////////////////////////////////////////
-    fn is_truthy(&self) -> bool {
+    pub fn is_truthy(&self) -> bool {
+        if let Value::Boolean(false) = self {
+            return false;
+        }
         if let Value::Nil = self {
             return false;
         }