Add lexing and parsing for I/O built-in functions; Refactor built-in function parsing

dust-lang/src/analyzer.rs

@@ -71,22 +71,23 @@ impl<'a> Analyzer<'a> {
     fn analyze_node(&self, node: &Node) -> Result<(), AnalyzerError> {
         match &node.statement {
             Statement::Add(left, right) => {
-                if let Some(Type::Integer) | Some(Type::Float) =
-                    left.statement.expected_type(self.variables)
-                {
-                } else {
-                    return Err(AnalyzerError::ExpectedIntegerOrFloat {
-                        actual: left.as_ref().clone(),
-                    });
-                }
+                let left_type = left.statement.expected_type(self.variables);
+                let right_type = right.statement.expected_type(self.variables);
 
-                if let Some(Type::Integer) | Some(Type::Float) =
-                    right.statement.expected_type(self.variables)
-                {
-                } else {
-                    return Err(AnalyzerError::ExpectedIntegerOrFloat {
-                        actual: right.as_ref().clone(),
-                    });
+                match (left_type, right_type) {
+                    (Some(Type::Integer), Some(Type::Integer)) => {}
+                    (Some(Type::Float), Some(Type::Float)) => {}
+                    (Some(Type::String), Some(Type::String)) => {}
+                    (Some(Type::Integer), _) | (Some(Type::Float), _) | (Some(Type::String), _) => {
+                        return Err(AnalyzerError::ExpectedIntegerFloatOrString {
+                            actual: right.as_ref().clone(),
+                        });
+                    }
+                    _ => {
+                        return Err(AnalyzerError::ExpectedIntegerFloatOrString {
+                            actual: left.as_ref().clone(),
+                        });
+                    }
                 }
 
                 self.analyze_node(left)?;
@@ -183,6 +184,7 @@ pub enum AnalyzerError {
     ExpectedIdentifier { actual: Node },
     ExpectedIdentifierOrValue { actual: Node },
     ExpectedIntegerOrFloat { actual: Node },
+    ExpectedIntegerFloatOrString { actual: Node },
     UnexpectedIdentifier { identifier: Node },
 }
 
@@ -192,6 +194,52 @@ mod tests {
 
     use super::*;
 
+    #[test]
+    fn add_expects_same_types() {
+        let abstract_tree = AbstractSyntaxTree {
+            nodes: [Node::new(
+                Statement::Add(
+                    Box::new(Node::new(Statement::Constant(Value::integer(1)), (0, 1))),
+                    Box::new(Node::new(Statement::Constant(Value::float(1.0)), (1, 2))),
+                ),
+                (0, 2),
+            )]
+            .into(),
+        };
+        let variables = HashMap::new();
+        let analyzer = Analyzer::new(&abstract_tree, &variables);
+
+        assert_eq!(
+            analyzer.analyze(),
+            Err(AnalyzerError::ExpectedIntegerFloatOrString {
+                actual: Node::new(Statement::Constant(Value::float(1.0)), (1, 2))
+            })
+        )
+    }
+
+    #[test]
+    fn add_expects_integer_float_or_string() {
+        let abstract_tree = AbstractSyntaxTree {
+            nodes: [Node::new(
+                Statement::Add(
+                    Box::new(Node::new(Statement::Constant(Value::boolean(true)), (0, 1))),
+                    Box::new(Node::new(Statement::Constant(Value::integer(1)), (1, 2))),
+                ),
+                (0, 2),
+            )]
+            .into(),
+        };
+        let variables = HashMap::new();
+        let analyzer = Analyzer::new(&abstract_tree, &variables);
+
+        assert_eq!(
+            analyzer.analyze(),
+            Err(AnalyzerError::ExpectedIntegerFloatOrString {
+                actual: Node::new(Statement::Constant(Value::boolean(true)), (0, 1))
+            })
+        )
+    }
+
     #[test]
     fn is_even_expects_number() {
         let abstract_tree = AbstractSyntaxTree {
@@ -277,32 +325,6 @@ mod tests {
         )
     }
 
-    #[test]
-    fn add_expect_integer_or_float() {
-        let abstract_tree = AbstractSyntaxTree {
-            nodes: [Node::new(
-                Statement::Add(
-                    Box::new(Node::new(Statement::Constant(Value::integer(1)), (0, 1))),
-                    Box::new(Node::new(
-                        Statement::Constant(Value::boolean(false)),
-                        (1, 2),
-                    )),
-                ),
-                (0, 2),
-            )]
-            .into(),
-        };
-        let variables = HashMap::new();
-        let analyzer = Analyzer::new(&abstract_tree, &variables);
-
-        assert_eq!(
-            analyzer.analyze(),
-            Err(AnalyzerError::ExpectedIntegerOrFloat {
-                actual: Node::new(Statement::Constant(Value::boolean(false)), (1, 2))
-            })
-        )
-    }
-
     #[test]
     fn assignment_expect_identifier() {
         let abstract_tree = AbstractSyntaxTree {

dust-lang/src/built_in_function.rs

@@ -1,4 +1,7 @@
-use std::fmt::{self, Display, Formatter};
+use std::{
+    fmt::{self, Display, Formatter},
+    io::{self, stdin},
+};
 
 use serde::{Deserialize, Serialize};
 
@@ -6,9 +9,16 @@ use crate::{Type, Value};
 
 #[derive(Debug, Clone, Eq, PartialEq, PartialOrd, Ord, Serialize, Deserialize)]
 pub enum BuiltInFunction {
+    // Integer and float tools
     IsEven,
     IsOdd,
+
+    // List tools
     Length,
+
+    // I/O
+    ReadLine,
+    WriteLine,
 }
 
 impl BuiltInFunction {
@@ -17,6 +27,8 @@ impl BuiltInFunction {
             BuiltInFunction::IsEven => "is_even",
             BuiltInFunction::IsOdd => "is_odd",
             BuiltInFunction::Length => "length",
+            BuiltInFunction::ReadLine => "read_line",
+            BuiltInFunction::WriteLine => "write_line",
         }
     }
 
@@ -24,13 +36,13 @@ impl BuiltInFunction {
         &self,
         _type_arguments: Option<Vec<Type>>,
         value_arguments: Option<Vec<Value>>,
-    ) -> Result<Value, BuiltInFunctionError> {
+    ) -> Result<Option<Value>, BuiltInFunctionError> {
         match self {
             BuiltInFunction::IsEven => {
                 if let Some(value_arguments) = value_arguments {
                     if value_arguments.len() == 1 {
                         if let Some(integer) = value_arguments[0].as_integer() {
-                            Ok(Value::boolean(integer % 2 == 0))
+                            Ok(Some(Value::boolean(integer % 2 == 0)))
                         } else {
                             Err(BuiltInFunctionError::ExpectedInteger)
                         }
@@ -45,7 +57,7 @@ impl BuiltInFunction {
                 if let Some(value_arguments) = value_arguments {
                     if value_arguments.len() == 1 {
                         if let Some(integer) = value_arguments[0].as_integer() {
-                            Ok(Value::boolean(integer % 2 != 0))
+                            Ok(Some(Value::boolean(integer % 2 != 0)))
                         } else {
                             Err(BuiltInFunctionError::ExpectedInteger)
                         }
@@ -60,7 +72,7 @@ impl BuiltInFunction {
                 if let Some(value_arguments) = value_arguments {
                     if value_arguments.len() == 1 {
                         if let Some(list) = value_arguments[0].as_list() {
-                            Ok(Value::integer(list.len() as i64))
+                            Ok(Some(Value::integer(list.len() as i64)))
                         } else {
                             Err(BuiltInFunctionError::ExpectedInteger)
                         }
@@ -71,6 +83,30 @@ impl BuiltInFunction {
                     Err(BuiltInFunctionError::WrongNumberOfValueArguments)
                 }
             }
+            BuiltInFunction::ReadLine => {
+                if value_arguments.is_none() {
+                    let mut input = String::new();
+
+                    stdin().read_line(&mut input)?;
+
+                    Ok(Some(Value::string(input)))
+                } else {
+                    Err(BuiltInFunctionError::WrongNumberOfValueArguments)
+                }
+            }
+            BuiltInFunction::WriteLine => {
+                if let Some(value_arguments) = value_arguments {
+                    if value_arguments.len() == 1 {
+                        println!("{}", value_arguments[0]);
+
+                        Ok(None)
+                    } else {
+                        Err(BuiltInFunctionError::WrongNumberOfValueArguments)
+                    }
+                } else {
+                    Err(BuiltInFunctionError::WrongNumberOfValueArguments)
+                }
+            }
         }
     }
 
@@ -79,6 +115,8 @@ impl BuiltInFunction {
             BuiltInFunction::IsEven => Some(Type::Boolean),
             BuiltInFunction::IsOdd => Some(Type::Boolean),
             BuiltInFunction::Length => Some(Type::Integer),
+            BuiltInFunction::ReadLine => Some(Type::String),
+            BuiltInFunction::WriteLine => None,
         }
     }
 }
@@ -92,5 +130,12 @@ impl Display for BuiltInFunction {
 #[derive(Debug, Clone, PartialEq)]
 pub enum BuiltInFunctionError {
     ExpectedInteger,
+    Io(io::ErrorKind),
     WrongNumberOfValueArguments,
 }
+
+impl From<io::Error> for BuiltInFunctionError {
+    fn from(error: io::Error) -> Self {
+        Self::Io(error.kind())
+    }
+}

dust-lang/src/lex.rs

@@ -108,6 +108,8 @@ impl<'a> Lexer<'a> {
             match c {
                 '0'..='9' => self.lex_number()?,
                 'a'..='z' | 'A'..='Z' => self.lex_alphabetical()?,
+                '"' => self.lex_string('"')?,
+                '\'' => self.lex_string('\'')?,
                 '+' => {
                     self.position += 1;
                     (Token::Plus, (self.position - 1, self.position))
@@ -248,11 +250,34 @@ impl<'a> Lexer<'a> {
             "is_even" => Token::IsEven,
             "is_odd" => Token::IsOdd,
             "length" => Token::Length,
+            "read_line" => Token::ReadLine,
+            "write_line" => Token::WriteLine,
             _ => Token::Identifier(Identifier::new(string)),
         };
 
         Ok((token, (start_pos, self.position)))
     }
+
+    fn lex_string(&mut self, delimiter: char) -> Result<(Token, Span), LexError> {
+        let start_pos = self.position;
+
+        self.next_char();
+
+        while let Some(c) = self.peek_char() {
+            if c == delimiter {
+                self.next_char();
+                break;
+            } else {
+                self.next_char();
+            }
+        }
+
+        let string = &self.source[start_pos + 1..self.position - 1];
+        Ok((
+            Token::String(string.to_string()),
+            (start_pos, self.position),
+        ))
+    }
 }
 
 #[derive(Debug, PartialEq, Clone)]
@@ -277,6 +302,34 @@ impl From<ParseIntError> for LexError {
 mod tests {
     use super::*;
 
+    #[test]
+    fn string_concatenation() {
+        let input = "'Hello, ' + 'world!'";
+
+        assert_eq!(
+            lex(input),
+            Ok(vec![
+                (Token::String("Hello, ".to_string()), (0, 9)),
+                (Token::Plus, (10, 11)),
+                (Token::String("world!".to_string()), (12, 20)),
+                (Token::Eof, (20, 20)),
+            ])
+        )
+    }
+
+    #[test]
+    fn string() {
+        let input = "'Hello, world!'";
+
+        assert_eq!(
+            lex(input),
+            Ok(vec![
+                (Token::String("Hello, world!".to_string()), (0, 15)),
+                (Token::Eof, (15, 15)),
+            ])
+        )
+    }
+
     #[test]
     fn r#true() {
         let input = "true";

dust-lang/src/parse.rs

@@ -206,6 +206,11 @@ impl<'src> Parser<'src> {
 
                 Ok(Node::new(Statement::Identifier(identifier), span))
             }
+            (Token::String(string), span) => {
+                self.next_token()?;
+
+                Ok(Node::new(Statement::Constant(Value::string(string)), span))
+            }
             (Token::LeftParenthesis, left_span) => {
                 self.next_token()?;
 
@@ -253,7 +258,19 @@ impl<'src> Parser<'src> {
                     }
                 }
             }
-            (Token::IsEven, left_span) => {
+            (
+                Token::IsEven | Token::IsOdd | Token::Length | Token::ReadLine | Token::WriteLine,
+                left_span,
+            ) => {
+                let function = match self.current.0 {
+                    Token::IsEven => BuiltInFunction::IsEven,
+                    Token::IsOdd => BuiltInFunction::IsOdd,
+                    Token::Length => BuiltInFunction::Length,
+                    Token::ReadLine => BuiltInFunction::ReadLine,
+                    Token::WriteLine => BuiltInFunction::WriteLine,
+                    _ => unreachable!(),
+                };
+
                 self.next_token()?;
 
                 if let (Token::LeftParenthesis, _) = self.current {
@@ -265,80 +282,38 @@ impl<'src> Parser<'src> {
                     });
                 }
 
-                if let (Token::RightParenthesis, _) = self.current {
-                    self.next_token()?;
-                } else {
-                    return Err(ParseError::ExpectedClosingParenthesis {
-                        actual: self.current.0.clone(),
-                        span: self.current.1,
-                    });
+                let mut value_arguments: Option<Vec<Node>> = None;
+
+                loop {
+                    if let (Token::RightParenthesis, _) = self.current {
+                        self.next_token()?;
+                        break;
+                    }
+
+                    if let (Token::Comma, _) = self.current {
+                        self.next_token()?;
+                        continue;
+                    }
+
+                    if let Ok(node) = self.parse_node(0) {
+                        if let Some(ref mut arguments) = value_arguments {
+                            arguments.push(node);
+                        } else {
+                            value_arguments = Some(vec![node]);
+                        }
+                    } else {
+                        return Err(ParseError::ExpectedClosingParenthesis {
+                            actual: self.current.0.clone(),
+                            span: self.current.1,
+                        });
+                    }
                 }
 
                 Ok(Node::new(
                     Statement::BuiltInFunctionCall {
-                        function: BuiltInFunction::IsEven,
+                        function,
                         type_arguments: None,
-                        value_arguments: None,
-                    },
-                    left_span,
-                ))
-            }
-            (Token::IsOdd, left_span) => {
-                self.next_token()?;
-
-                if let (Token::LeftParenthesis, _) = self.current {
-                    self.next_token()?;
-                } else {
-                    return Err(ParseError::ExpectedOpeningParenthesis {
-                        actual: self.current.0.clone(),
-                        span: self.current.1,
-                    });
-                }
-
-                if let (Token::RightParenthesis, _) = self.current {
-                    self.next_token()?;
-                } else {
-                    return Err(ParseError::ExpectedClosingParenthesis {
-                        actual: self.current.0.clone(),
-                        span: self.current.1,
-                    });
-                }
-
-                Ok(Node::new(
-                    Statement::BuiltInFunctionCall {
-                        function: BuiltInFunction::IsOdd,
-                        type_arguments: None,
-                        value_arguments: None,
-                    },
-                    left_span,
-                ))
-            }
-            (Token::Length, left_span) => {
-                self.next_token()?;
-
-                if let (Token::LeftParenthesis, _) = self.current {
-                    self.next_token()?;
-                } else {
-                    return Err(ParseError::ExpectedOpeningParenthesis {
-                        actual: self.current.0.clone(),
-                        span: self.current.1,
-                    });
-                }
-
-                if let (Token::RightParenthesis, _) = self.current {
-                    self.next_token()?;
-                } else {
-                    return Err(ParseError::ExpectedClosingParenthesis {
-                        actual: self.current.0.clone(),
-                        span: self.current.1,
-                    });
-                }
-
-                Ok(Node::new(
-                    Statement::BuiltInFunctionCall {
-                        function: BuiltInFunction::Length,
-                        type_arguments: None,
-                        value_arguments: None,
+                        value_arguments,
                     },
                     left_span,
                 ))
@@ -379,6 +354,47 @@ mod tests {
 
     use super::*;
 
+    #[test]
+    fn string_concatenation() {
+        let input = "\"Hello, \" + \"World!\"";
+
+        assert_eq!(
+            parse(input),
+            Ok(AbstractSyntaxTree {
+                nodes: [Node::new(
+                    Statement::Add(
+                        Box::new(Node::new(
+                            Statement::Constant(Value::string("Hello, ")),
+                            (0, 9)
+                        )),
+                        Box::new(Node::new(
+                            Statement::Constant(Value::string("World!")),
+                            (12, 20)
+                        ))
+                    ),
+                    (0, 20)
+                )]
+                .into()
+            })
+        );
+    }
+
+    #[test]
+    fn string() {
+        let input = "\"Hello, World!\"";
+
+        assert_eq!(
+            parse(input),
+            Ok(AbstractSyntaxTree {
+                nodes: [Node::new(
+                    Statement::Constant(Value::string("Hello, World!")),
+                    (0, 15)
+                )]
+                .into()
+            })
+        );
+    }
+
     #[test]
     fn boolean() {
         let input = "true";

dust-lang/src/token.rs

@@ -14,22 +14,25 @@ pub enum Token {
     Boolean(bool),
     Float(f64),
     Integer(i64),
+    String(String),
 
     // Keywords
     IsEven,
     IsOdd,
     Length,
+    ReadLine,
+    WriteLine,
 
     // Symbols
     Comma,
     Dot,
     Equal,
-    Plus,
-    Star,
     LeftParenthesis,
-    RightParenthesis,
     LeftSquareBrace,
+    Plus,
+    RightParenthesis,
     RightSquareBrace,
+    Star,
 }
 
 impl Display for Token {
@@ -40,9 +43,12 @@ impl Display for Token {
             Token::Boolean(boolean) => write!(f, "{boolean}"),
             Token::Float(float) => write!(f, "{float}"),
             Token::Integer(integer) => write!(f, "{integer}"),
+            Token::String(string) => write!(f, "{string}"),
             Token::IsEven => write!(f, "is_even"),
             Token::IsOdd => write!(f, "is_odd"),
             Token::Length => write!(f, "length"),
+            Token::ReadLine => write!(f, "read_line"),
+            Token::WriteLine => write!(f, "write_line"),
             Token::Comma => write!(f, ","),
             Token::Dot => write!(f, "."),
             Token::Equal => write!(f, "="),

dust-lang/src/value.rs

@@ -527,18 +527,6 @@ impl ValueInner {
     }
 }
 
-pub trait ValueProperties<'a> {}
-
-pub struct IntegerProperties<'a>(&'a Value);
-
-impl<'a> IntegerProperties<'a> {
-    pub fn is_even(&self) -> bool {
-        self.0.as_integer().unwrap() % 2 == 0
-    }
-}
-
-impl<'a> ValueProperties<'a> for IntegerProperties<'a> {}
-
 impl Eq for ValueInner {}
 
 impl PartialOrd for ValueInner {

dust-lang/src/vm.rs

@@ -114,7 +114,7 @@ impl Vm {
                 };
                 let function_call_return = function.call(None, values)?;
 
-                Ok(Some(function_call_return))
+                Ok(function_call_return)
             }
             Statement::Constant(value) => Ok(Some(value.clone())),
             Statement::FunctionCall {
@@ -226,7 +226,7 @@ impl Vm {
 
                     let function_call_return = function.call(None, Some(value_arguments))?;
 
-                    return Ok(Some(function_call_return));
+                    return Ok(function_call_return);
                 }
 
                 Err(VmError::ExpectedIdentifierOrInteger {

dust_examples/hello_world.ds

@@ -1,8 +1,6 @@
-use std.io
+write_line("Hello, world!")
+write_line("Enter your name...")
 
-io.write_line("Hello, world!")
-io.write_line("Enter your name...")
+name = read_line()
 
-message = io.read_line()
-
-io.write_line("Hello " + message + "!")
+write_line("Hello " + name + "!")