Cleaning repl

Cleaning repl, removing multi-statement repl, further implementation as
separated code from the rest

Signed-off-by: teo3300 <matteo.rogora@live.it>

src/main.rs

@@ -29,10 +29,8 @@ fn main() -> io::Result<()> {
             // Perform rep on whole available input
             match rep(&input) {
                 Ok(output) => {
-                    for el in output {
-                        num += 1;
-                        println!("[{}]> {}", num, el);
-                    }
+                    num += 1;
+                    println!("[{}]> {}", num, output);
                 }
                 Err(err) => {
                     if line == "\n" {

src/reader.rs

@@ -19,26 +19,23 @@ impl Reader {
         Reader { tokens, ptr: 0 }
     }
 
-    fn avail(&self) -> bool {
-        self.ptr < self.tokens.len()
+    // May be improved
+    fn get_token(&self, i: usize) -> Result<String, MalErr> {
+        match self.tokens.get(i) {
+            Some(token) => Ok(token.to_string()),
+            None => Err("Unexpected EOF".to_string()),
+        }
     }
 
     /// Returns the token at the current position
     fn peek(&self) -> Result<String, MalErr> {
-        match self.tokens.get(self.ptr) {
-            Some(token) => Ok(token.to_string()),
-            None => Err("Unexpected EOF, Missing parenthesis?".to_string()),
-        }
+        self.get_token(self.ptr)
     }
 
     /// Returns the token at current position and increment current position
-    // TODO: PLEASE USE THE PEEK FUNCTION
     fn next(&mut self) -> Result<String, MalErr> {
         self.ptr += 1;
-        match self.tokens.get(self.ptr - 1) {
-            Some(token) => Ok(token.to_string()),
-            None => Err("Unexpected EOF, Missing parenthesis?".to_string()),
-        }
+        self.get_token(self.ptr - 1)
     }
 
     /// Repeatedly calls `read_form` of the reader object until it finds a ")" token
@@ -50,44 +47,36 @@ impl Reader {
         self.next()?;
 
         let mut vector = Vec::new();
-        loop {
-            let token = self.peek()?;
-            if token == terminator {
-                break;
-            }
+
+        while self.peek()? != terminator {
             vector.push(self.read_form()?)
         }
         self.next()?;
+
         match terminator {
             ")" => Ok(List(vector)),
             "]" => Ok(Vector(vector)),
             "}" => make_map(vector),
-            _ => Err(format!("Unknown collection terminator: {}", terminator)),
+            _ => Err("Unknown collection terminator".to_string()),
         }
     }
 
     /// Read atomic token and return appropriate scalar ()
     fn read_atom(&mut self) -> MalRet {
-        let token = self.next()?;
-        let re_digits = Regex::new(r"^-?[0-9]+$").unwrap();
-        match token.as_str() {
-            ")" | "]" | "}" => Err(format!("Lone parenthesis {}", token)),
+        match &self.next()?[..] {
+            ")" | "]" | "}" => Err("Missing open parenthesis".to_string()),
             "false" => Ok(Bool(false)),
             "true" => Ok(Bool(true)),
             "nil" => Ok(Nil),
-            _ => {
-                if re_digits.is_match(&token) {
-                    Ok(Int(token.parse::<isize>().unwrap()))
-                } else if token.starts_with('\"') {
-                    if token.ends_with('\"') {
-                        Ok(Str(map_key(KeyVar::Str, &unescape_str(&token))))
-                    } else {
-                        Err("Unterminated string, expected \"".to_string())
-                    }
-                } else if token.starts_with(':') {
-                    Ok(Key(map_key(KeyVar::Key, &token)))
+            tk => {
+                if Regex::new(r"^-?[0-9]+$").unwrap().is_match(tk) {
+                    Ok(Int(tk.parse::<isize>().unwrap()))
+                } else if tk.starts_with('\"') {
+                    Ok(Str(map_key(KeyVar::Str, &unescape_str(tk))))
+                } else if tk.starts_with(':') {
+                    Ok(Key(map_key(KeyVar::Key, tk)))
                 } else {
-                    Ok(Sym(map_key(KeyVar::Sym, &token)))
+                    Ok(Sym(map_key(KeyVar::Sym, tk)))
                 }
             }
         }
@@ -99,9 +88,8 @@ impl Reader {
     /// "(" -> call `read_list`
     /// otherwise  -> call `read_atom`
     fn read_form(&mut self) -> MalRet {
-        let token = self.peek()?;
         // String slice containing the whole string
-        match &token[..] {
+        match &self.peek()?[..] {
             // Consume "(" and parse list
             "(" => self.read_list(")"),
             "[" => self.read_list("]"),
@@ -114,43 +102,17 @@ impl Reader {
 /// Call `tokenize` on a string
 /// Create anew Reader with the tokens
 /// Call read_from with the reader instance
-/// TODO: catch errors
-pub fn read_str(input: &str) -> Result<Vec<MalType>, MalErr> {
-    let tokens = tokenize(input);
-    match tokens.len() {
-        0 => Ok(vec![Nil]),
-        _ => {
-            let mut reader = Reader::new(tokens);
-            let mut res = Vec::new();
-            while reader.avail() {
-                match reader.read_form() {
-                    Err(err) => return Err(err),
-                    Ok(any) => res.push(any),
-                };
-            }
-            Ok(res)
-        }
-    }
+pub fn read_str(input: &str) -> MalRet {
+    Reader::new(tokenize(input)).read_form()
 }
 
 /// Read a string and return a list of tokens in it (following regex in README)
 // Add error handling for strings that are not terminated
 fn tokenize(input: &str) -> Vec<String> {
-    let mut tokens = Vec::new();
-
-    let re = Regex::new(
-        r###"[\s,]*(~@|[\[\]{}()'`~^@]|"(?:\\.|[^\\"])*"?|;.*\n|[^\s\[\]{}('"`,;)]*)"###,
-    )
-    .unwrap();
-    for match_str in re.captures_iter(input) {
-        if !match_str[1].is_empty() {
-            // Drop comments
-            if match_str[1].starts_with(';') {
-                continue;
-            }
-            tokens.push(match_str[1].to_string());
-        }
-    }
-
-    tokens
+    Regex::new(r###"[\s,]*(~@|[\[\]{}()'`~^@]|"(?:\\.|[^\\"])*"?|;.*\n|[^\s\[\]{}('"`,;)]*)"###)
+        .unwrap()
+        .captures_iter(input)
+        .map(|e| e[1].to_string())
+        .filter(|e| !e.is_empty() || !e.starts_with(';'))
+        .collect::<Vec<String>>()
 }

src/step1_read_print.rs

@@ -6,11 +6,11 @@
 
 use crate::printer::pr_str;
 use crate::reader::read_str;
-use crate::types::{MalErr, MalType};
+use crate::types::{MalRet, MalType};
 
 #[allow(non_snake_case)]
 /// Read input and generate an ast
-fn READ(input: &str) -> Result<Vec<MalType>, MalErr> {
+fn READ(input: &str) -> MalRet {
     match read_str(input) {
         Ok(ast) => Ok(ast),
         Err(err) => Err(format!("@ READ: {}", err)),
@@ -19,22 +19,18 @@ fn READ(input: &str) -> Result<Vec<MalType>, MalErr> {
 
 #[allow(non_snake_case)]
 /// Evaluate the generated ast
-fn EVAL(ast: Vec<MalType>) -> Vec<MalType> {
-    ast
+fn EVAL(ast: MalType) -> MalRet {
+    Ok(ast)
 }
 
 #[allow(non_snake_case)]
 /// Print out the result of the evaluation
-fn PRINT(input: Vec<MalType>) -> Vec<String> {
-    let mut ret = Vec::new();
-    for expr in input {
-        ret.push(pr_str(&expr, true))
-    }
-    ret
+fn PRINT(output: MalType) -> String {
+    pr_str(&output, true)
 }
 
-pub fn rep(input: &str) -> Result<Vec<String>, MalErr> {
+pub fn rep(input: &str) -> Result<String, String> {
     let ast = READ(input)?;
-    let out = EVAL(ast);
+    let out = EVAL(ast)?;
     Ok(PRINT(out))
 }