add string split method

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "relish"
 version = "0.1.0"
-authors = ["Aidan <aidan@aidanis.online>"]
+authors = ["Ava <ava@sunnypup.io>"]
 edition = "2018"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
@@ -9,4 +9,3 @@ edition = "2018"
 [dependencies]
 dirs = "3.0"
 rustyline = "8.2.0"
-once_cell = "1.17.1"

src/stl.rs

@@ -74,6 +74,17 @@ pub fn static_stdlib(syms: &mut SymTable) -> Result<(), String> {
         },
     );
 
+    syms.insert(
+        "split".to_string(),
+        Symbol {
+            name: String::from("split"),
+            args: Args::Strict(vec![Type::String, Type::String]),
+            conditional_branches: false,
+            docs: strings::SPLIT_DOCSTRING.to_string(),
+            value: ValueType::Internal(Rc::new(strings::split_callback)),
+        },
+    );
+
     syms.insert(
         "strlen".to_string(),
         Symbol {

src/stl/strings.rs

@@ -115,3 +115,36 @@ pub fn contains_callback(ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String>
 
     Ok(Ctr::Bool(parent_str.contains(&child_str)))
 }
+
+pub const SPLIT_DOCSTRING: &str = "Takes two strings. String 1 is a source string and string 2 is a delimiter.
+Returns a list of substrings from string 1 that were found delimited by string 2.";
+
+pub fn split_callback(ast: &Seg, _syms: &mut SymTable) -> Result<Ctr, String> {
+    let parent_str: String;
+    if let Ctr::String(ref s) = *ast.car {
+        parent_str = s.to_string();
+    } else {
+        return Err("first argument must be a string".to_string());
+    }
+
+    let second_arg_obj: &Ctr;
+    let delim_str: String;
+    if let Ctr::Seg(ref s) = *ast.cdr {
+        second_arg_obj = &*s.car;
+    } else {
+        return Err("impossible error: needs two arguments".to_string());
+    }
+
+    if let Ctr::String(ref s) = &*second_arg_obj {
+        delim_str = s.clone();
+    } else {
+        return Err("second argument must be a string".to_string());
+    }
+
+    let mut ret = Seg::new();
+    for substr in parent_str.split(&delim_str) {
+        ret.append(Box::new(Ctr::String(substr.to_string())));
+    }
+
+    Ok(Ctr::Seg(ret))
+}

tests/test_lib_str.rs

@@ -181,4 +181,49 @@ mod str_lib_tests {
             result.to_string(),
         );
     }
+
+    #[test]
+    fn test_split() {
+        let document = "(split 'one.two.three' '.')";
+        let result = "('one' 'two' 'three')";
+        let mut syms = SymTable::new();
+        static_stdlib(&mut syms).unwrap();
+        dynamic_stdlib(&mut syms).unwrap();
+        assert_eq!(
+            *eval(&lex(&document.to_string()).unwrap(), &mut syms)
+                .unwrap()
+                .to_string(),
+            result.to_string(),
+        );
+    }
+
+    #[test]
+    fn test_split_big_delim() {
+        let document = "(split 'one:d:two:d:three' ':d:')";
+        let result = "('one' 'two' 'three')";
+        let mut syms = SymTable::new();
+        static_stdlib(&mut syms).unwrap();
+        dynamic_stdlib(&mut syms).unwrap();
+        assert_eq!(
+            *eval(&lex(&document.to_string()).unwrap(), &mut syms)
+                .unwrap()
+                .to_string(),
+            result.to_string(),
+        );
+    }
+
+    #[test]
+    fn test_splitnt() {
+        let document = "(split 'one.two.three' '-')";
+        let result = "('one.two.three')";
+        let mut syms = SymTable::new();
+        static_stdlib(&mut syms).unwrap();
+        dynamic_stdlib(&mut syms).unwrap();
+        assert_eq!(
+            *eval(&lex(&document.to_string()).unwrap(), &mut syms)
+                .unwrap()
+                .to_string(),
+            result.to_string(),
+        );
+    }
 }