division symbol is now /

Author: erkkikeranen

src/clojure/core.clj

@@ -47,7 +47,7 @@
 (defmacro time [expr]
  (list (quote let) [(quote start) (quote (System/nanoTime)) (quote ret) expr]
  (quote (do
- (println (str "Elapsed time: " (_slash_ (- (System/nanoTime) start) 1000000.0) " msecs"))
+ (println (str "Elapsed time: " (/ (- (System/nanoTime) start) 1000000.0) " msecs"))
  ret))))
 
 (defn slurp [f & opts]

src/environment.rs

@@ -249,6 +249,7 @@ impl Environment {
  let subtract_fn = rust_core::SubtractFn {};
  let multiply_fn = rust_core::MultiplyFn {};
  let divide_fn = rust_core::DivideFn {};
+ let rem_fn = rust_core::RemFn {};
  let rand_fn = rust_core::RandFn {};
  let rand_int_fn = rust_core::RandIntFn {};
  let str_fn = rust_core::StrFn {};
@@ -315,7 +316,8 @@ impl Environment {
  environment.insert(Symbol::intern("+"), add_fn.to_rc_value());
  environment.insert(Symbol::intern("-"), subtract_fn.to_rc_value());
  environment.insert(Symbol::intern("*"), multiply_fn.to_rc_value());
- environment.insert(Symbol::intern("_slash_"), divide_fn.to_rc_value());
+ environment.insert(Symbol::intern("/"), divide_fn.to_rc_value());
+ environment.insert(Symbol::intern("rem"), rem_fn.to_rc_value());
  environment.insert(Symbol::intern("rand"), rand_fn.to_rc_value());
  environment.insert(Symbol::intern("rand-int"), rand_int_fn.to_rc_value());
  environment.insert(Symbol::intern("let"), let_macro.to_rc_value());

src/reader.rs

@@ -148,7 +148,7 @@ fn is_period_char(chr: char) -> bool {
 ///
 /// Clojure defines a whitespace as either a comma or an unicode whitespace.
 fn is_clojure_whitespace(c: char) -> bool {
- c.is_whitespace() || c == ',' 
+ c.is_whitespace() || c == ','
 }
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 // End predicates
@@ -169,16 +169,16 @@ fn consume_clojure_whitespaces_parser(input: &str) -> IResult<&str, ()> {
 
  named!(whitespace_parser<&str,()>,
  value!((),
- many0!(alt!(comment_parser | 
+ many0!(alt!(comment_parser |
  take_while1!(is_clojure_whitespace))))
  );
 
  named!(no_whitespace_parser<&str,()>, value!((),tag!("")));
 
- // @TODO rename / check that all parsers are consistent? 
+ // @TODO rename / check that all parsers are consistent?
  named!(parser<&str,()>,
  // Because 'whitespace_parser' loops, we cannot include the case where there's no whitespace at all in
- // its definition -- nom wouldn't allow it, as it would loop forever consuming no whitespace 
+ // its definition -- nom wouldn't allow it, as it would loop forever consuming no whitespace
  // So instead, we eat up all the whitespace first, and then use the no_whitespace_parser as our sort-of
  // base-case after
  alt!(whitespace_parser | no_whitespace_parser)
@@ -432,6 +432,16 @@ pub fn try_read_pattern(input: &str) -> IResult<&str, Value> {
  Ok((rest_input, regex))
 }
 
+/// This reader is needed for parsing the division sign /
+pub fn try_read_division_forward_slash(input: &str) -> IResult<&str, Value> {
+ named!(slash_parser<&str, &str>, preceded!(consume_clojure_whitespaces_parser, tag!("/")));
+
+ let (rest_input, slash) = slash_parser(input)?;
+
+ // If an error is thrown, this will be coerced into a condition
+ Ok((rest_input, Value::Symbol(Symbol::intern(slash))))
+}
+
 // @TODO Perhaps generalize this, or even generalize it as a reader macro
 /// Tries to parse &str into Value::PersistentListMap, or some other Value::..Map
 /// Example Successes:
@@ -533,6 +543,7 @@ pub fn try_read(input: &str) -> IResult<&str, Value> {
  try_read_bool,
  try_read_nil,
  try_read_symbol,
+ try_read_division_forward_slash,
  try_read_keyword,
  try_read_list,
  try_read_vector,
@@ -560,12 +571,15 @@ pub fn read<R: BufRead>(reader: &mut R) -> Value {
  // loop over and ask for more lines, accumulating them in input_buffer until we can read
  loop {
  let maybe_line = reader.by_ref().lines().next();
- 
+
  match maybe_line {
  Some(Err(e)) => return Value::Condition(format!("Reader error: {}", e)),
  // `lines` does not include \n, but \n is part of the whitespace given to the reader
- // (and is important for reading comments) so we will push a newline as well 
- Some(Ok(line)) => { input_buffer.push_str(&line); input_buffer.push_str("\n"); },
+ // (and is important for reading comments) so we will push a newline as well
+ Some(Ok(line)) => {
+ input_buffer.push_str(&line);
+ input_buffer.push_str("\n");
+ }
  None => {
  return Value::Condition(String::from("Tried to read empty stream; unexpected EOF"))
  }
@@ -881,6 +895,14 @@ mod tests {
  fn try_read_bool_false_test() {
  assert_eq!(Value::Boolean(false), try_read("false ").ok().unwrap().1)
  }
+
+ #[test]
+ fn try_read_forward_slash_test() {
+ assert_eq!(
+ Value::Symbol(Symbol::intern(&"/")),
+ try_read("/ ").ok().unwrap().1
+ );
+ }
  }
 
  mod regex_tests {

src/rust_core.rs

@@ -29,6 +29,9 @@ pub use self::_divide_::*;
 pub(crate) mod _multiply_;
 pub use self::_multiply_::*;
 
+pub(crate) mod rem;
+pub use self::rem::*;
+
 pub(crate) mod rand;
 pub use self::rand::*;
 

src/rust_core/_divide_.rs

@@ -20,6 +20,8 @@ impl IFn for DivideFn {
  1 => {
  let val = args.get(0).unwrap().to_value();
  match val {
+ Value::I32(0) => Value::Condition("Divide by zero".to_string()),
+ Value::F64(0.0) => Value::Condition("Divide by zero".to_string()),
  Value::I32(a_) => Value::F64(1.0 / a_ as f64),
  Value::F64(f_) => Value::F64(1.0 / f_),
  _ => Value::Condition(format!(
@@ -34,6 +36,8 @@ impl IFn for DivideFn {
  let first_arg = args_iterator.next().unwrap();
  args_iterator.fold(first_arg.to_value(), |a, b| match a {
  Value::I32(a_) => match *b {
+ Value::I32(0) => Value::Condition("Divide by zero".to_string()),
+ Value::F64(0.0) => Value::Condition("Divide by zero".to_string()),
  Value::I32(b_) => Value::I32(a_ / b_),
  Value::F64(b_) => Value::F64(a_ as f64 / b_),
  _ => Value::Condition(format!(
@@ -43,6 +47,8 @@ impl IFn for DivideFn {
  )),
  },
  Value::F64(a_) => match *b {
+ Value::I32(0) => Value::Condition("Divide by zero".to_string()),
+ Value::F64(0.0) => Value::Condition("Divide by zero".to_string()),
  Value::I32(b_) => Value::F64(a_ / b_ as f64),
  Value::F64(b_) => Value::F64(a_ / b_),
  _ => Value::Condition(format!(

src/rust_core/rem.rs

@@ -0,0 +1,82 @@
+use crate::ifn::IFn;
+use crate::value::{ToValue, Value};
+use std::rc::Rc;
+
+use crate::error_message;
+
+/// (rem x y)
+/// Calculate remainder
+#[derive(Debug, Clone)]
+pub struct RemFn {}
+impl ToValue for RemFn {
+ fn to_value(&self) -> Value {
+ Value::IFn(Rc::new(self.clone()))
+ }
+}
+impl IFn for RemFn {
+ fn invoke(&self, args: Vec<Rc<Value>>) -> Value {
+ match args.len() {
+ 2 => {
+ match args.get(0).unwrap().to_value() {
+ Value::I32(a_) => match args.get(1).unwrap().to_value() {
+ Value::I32(0) => Value::Condition("Divide by zero".to_string()),
+ Value::F64(0.0) => Value::Condition("Divide by zero".to_string()),
+ Value::I32(b_) => Value::I32(a_ % b_),
+ Value::F64(b_) => Value::F64(a_ as f64 % b_),
+ _b => Value::Condition(format!(
+ // TODO: what error message should be returned regarding using typetags?
+ "Type mismatch; Expecting: (i32 | i64 | f32 | f64), Found: {}",
+ _b.type_tag()
+ )),
+ },
+ Value::F64(a_) => match args.get(1).unwrap().to_value() {
+ Value::I32(0) => Value::Condition("Divide by zero".to_string()),
+ Value::F64(0.0) => Value::Condition("Divide by zero".to_string()),
+ Value::I32(b_) => Value::F64(a_ % b_ as f64),
+ Value::F64(b_) => Value::F64(a_ % b_),
+ _b => Value::Condition(format!(
+ // TODO: what error message should be returned regarding using typetags?
+ "Type mismatch; Expecting: (i32 | i64 | f32 | f64), Found: {}",
+ _b.type_tag()
+ )),
+ },
+ _a => Value::Condition(format!(
+ // TODO: what error message should be returned regarding using typetags?
+ "Type mismatch: Expecting: (i32 | i64 | f32 | f64), Found: {}",
+ _a.type_tag()
+ )),
+ }
+ }
+ _ => error_message::wrong_arg_count(2, args.len()),
+ }
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ mod rem_tests {
+ use crate::ifn::IFn;
+ use crate::rust_core::rem::RemFn;
+ use crate::value::Value;
+ use std::rc::Rc;
+
+ #[test]
+ fn rem_without_arguments_returns_error() {
+ let rem = RemFn {};
+ let args = vec![];
+ assert_eq!(
+ Value::Condition(String::from(
+ "Wrong number of arguments given to function (Given: 0, Expected: 2)"
+ )),
+ rem.invoke(args)
+ );
+ }
+
+ #[test]
+ fn rem_with_two_integer_argument_returns_remainder() {
+ let rem = RemFn {};
+ let args = vec![Rc::new(Value::I32(10)), Rc::new(Value::I32(3))];
+ assert_eq!(Value::I32(1), rem.invoke(args));
+ }
+ }
+}

src/symbol.rs

@@ -28,8 +28,12 @@ impl Symbol {
  // we need to make sure each 'character' in this case
  // is 1 byte, and not some other grapheme abstraction
  // else,these are two different indexes
- ns = &name[..ind];
- name = &name[ind + 1..];
+
+ // support interning of the symbol '/' for division
+ if ind > 0 || name.len() > 1 {
+ ns = &name[..ind];
+ name = &name[ind + 1..];
+ }
  }
  Symbol::intern_with_ns(ns, name)
  }