trim-newline

Author: erkkikeranen

src/clojure_string.rs

@@ -6,6 +6,7 @@ pub(crate) mod lower_case;
 pub(crate) mod reverse;
 pub(crate) mod starts_with_qmark_;
 pub(crate) mod trim;
+pub(crate) mod trim_newline;
 pub(crate) mod triml;
 pub(crate) mod trimr;
 pub(crate) mod upper_case;

src/clojure_string/trim_newline.rs

@@ -0,0 +1,60 @@
+use crate::ifn::IFn;
+use crate::value::{ToValue, Value};
+use std::rc::Rc;
+
+use crate::error_message;
+use crate::type_tag::TypeTag;
+
+/// clojure.string/trim_newline trims white space from start of string
+#[derive(Debug, Clone)]
+pub struct TrimNewlineFn {}
+impl ToValue for TrimNewlineFn {
+    fn to_value(&self) -> Value {
+        Value::IFn(Rc::new(self.clone()))
+    }
+}
+impl IFn for TrimNewlineFn {
+    fn invoke(&self, args: Vec<Rc<Value>>) -> Value {
+        if args.len() != 1 {
+            return error_message::wrong_arg_count(1, args.len());
+        } else {
+            match args.get(0).unwrap().to_value() {
+                Value::String(s) => {
+                    Value::String(s.trim_end_matches(|c| c == '\n' || c == '\r').to_string())
+                }
+                _a => error_message::type_mismatch(TypeTag::String, &_a.to_value()),
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    mod trim_newline_tests {
+        use crate::clojure_string::trim_newline::TrimNewlineFn;
+        use crate::ifn::IFn;
+        use crate::value::Value;
+        use std::rc::Rc;
+
+        #[test]
+        fn trim_newline() {
+            let trim_newline = TrimNewlineFn {};
+            let s = " \r \t  hello   \n\r";
+            let args = vec![Rc::new(Value::String(String::from(s)))];
+            assert_eq!(
+                Value::String(String::from(" \r \t  hello   ")),
+                trim_newline.invoke(args)
+            );
+        }
+        #[test]
+        fn trim_newline_does_nothing() {
+            let trim_newline = TrimNewlineFn {};
+            let s = " \r \t  hello   . ";
+            let args = vec![Rc::new(Value::String(String::from(s)))];
+            assert_eq!(
+                Value::String(String::from(" \r \t  hello   . ")),
+                trim_newline.invoke(args)
+            );
+        }
+    }
+}

src/environment.rs

@@ -214,6 +214,7 @@ impl Environment {
         let trim_fn = clojure_string::trim::TrimFn {};
         let triml_fn = clojure_string::triml::TrimLFn {};
         let trimr_fn = clojure_string::trimr::TrimRFn {};
+        let trim_newline_fn = clojure_string::trim_newline::TrimNewlineFn {};
 
         // Hardcoded fns
         let lexical_eval_fn = Value::LexicalEvalFn {};
@@ -327,6 +328,12 @@ impl Environment {
             trimr_fn.to_rc_value(),
         );
 
+        environment.insert_into_namespace(
+            &Symbol::intern("clojure.string"),
+            Symbol::intern("trim-newline"),
+            trim_newline_fn.to_rc_value(),
+        );
+
         environment.insert(Symbol::intern("+"), add_fn.to_rc_value());
         environment.insert(Symbol::intern("let"), let_macro.to_rc_value());
         environment.insert(Symbol::intern("str"), str_fn.to_rc_value());