lexer code

src/bong/lexer.rs

@@ -1,68 +1,278 @@
-use std::{iter::Peekable, str::Chars};
+enum LexerErrorType {
+    UnexpectedToken(char),
+    InvalidConstructor,
+}
 
-pub enum TokenType {
-    SinglelineWhitespace,
-    MultilineWhitespace,
-    SinglelineComment,
-    MultilineComment,
+struct LexerError {
+    error: LexerErrorType,
+    line: isize,
+    col: isize,
+}
 
+enum Token {
+    Name(String),
+    Class(String),
+    SlWhitespace(String),
+    MlWhitespace(String),
+    SlComment(String),
+    String(String),
+    LBrace(String),
+    RBrace(String),
+}
+
+enum Mode {
     Name,
-    Id,
     Class,
-
-    Int,
-    Float,
     String,
-    Null,
-    False,
-    True,
-
-    LBrace,
-    RBrace,
-    LBracket,
-    RBracket,
-
-    Equal,
-    Colon,
-    SemiColon,
-    Comma,
+    EscapedString,
+    SlWhitespace,
+    MlWhitespace,
+    SlComment,
 }
 
-pub struct Token<'a> {
-    token_type: TokenType,
-    value: &'a str,
-    line: u32,
-    col: u32,
-}
-
-pub struct LexerError {
-    line: u32,
-    col: u32,
-    message: String,
-}
-
-impl LexerError {
-    pub fn new(line: u32, col: u32, message: String) -> Self {
-        Self { line, col, message }
-    }
-}
-
-pub struct Lexer<'a> {
-    phantom: std::marker::PhantomData<&'a u32>,
-}
-
-impl<'a> Lexer<'a> {
-    pub fn new(text: &'a str) -> Self {
-        Self {
-            phantom: std::marker::PhantomData {},
+impl Mode {
+    fn token_constructor(&self) -> Result<Box<dyn Fn(String) -> Token>, LexerErrorType> {
+        match self {
+            Mode::Name => Ok(Box::new(Token::Name)),
+            Mode::Class => Ok(Box::new(Token::Class)),
+            Mode::String => Ok(Box::new(Token::String)),
+            Mode::SlWhitespace => Ok(Box::new(Token::SlWhitespace)),
+            Mode::MlWhitespace => Ok(Box::new(Token::MlWhitespace)),
+            Mode::SlComment => Ok(Box::new(Token::SlComment)),
+            Mode::EscapedString => Err(LexerErrorType::InvalidConstructor),
         }
     }
 }
 
-impl<'a> Iterator for Lexer<'a> {
-    type Item = Result<Token<'a>, String>;
-
-    fn next(&mut self) -> Option<Self::Item> {
-        todo!()
+fn lex(code: String) -> Result<Vec<Token>, LexerError> {
+    let mut tokens = Vec::new();
+    let mut value = Vec::new();
+    let mut iter = code.chars();
+    let mut mode = Mode::SlWhitespace;
+    let mut line = 0;
+    let mut col = 0;
+    let position_map = move |error: LexerErrorType| LexerError { error, line, col };
+    loop {
+        let c = iter.next();
+        if c.is_none() {
+            break;
+        };
+        match c.unwrap() {
+            '.' => {
+                match mode {
+                    m @ Mode::Name
+                    | m @ Mode::Class
+                    | m @ Mode::SlWhitespace
+                    | m @ Mode::MlWhitespace => {
+                        let string_value = value.iter().collect();
+                        let constructor = m.token_constructor().map_err(position_map)?;
+                        tokens.push(constructor(string_value));
+                        value.clear();
+                        mode = Mode::Class;
                     }
+                    Mode::String | Mode::SlComment => {}
+                    Mode::EscapedString => {
+                        return Err(LexerError {
+                            line,
+                            col,
+                            error: LexerErrorType::UnexpectedToken('.'),
+                        })
+                    }
+                };
+                value.push('.');
+            }
+            '\\' => match mode {
+                Mode::String => {
+                    value.push('\\');
+                    mode = Mode::EscapedString;
+                }
+                _ => {
+                    return Err(LexerError {
+                        line,
+                        col,
+                        error: LexerErrorType::UnexpectedToken('\\'),
+                    })
+                }
+            },
+            '"' => {
+                match mode {
+                    m @ Mode::String => {
+                        mode = Mode::SlWhitespace;
+                        value.push('"');
+                        let string_value = value.iter().collect();
+                        let constructor = m.token_constructor().map_err(position_map)?;
+                        tokens.push(constructor(string_value));
+                        value.clear();
+                    }
+                    m @ Mode::SlWhitespace | m @ Mode::MlWhitespace => {
+                        mode = Mode::String;
+                        let string_value = value.iter().collect();
+                        let constructor = m.token_constructor().map_err(position_map)?;
+                        tokens.push(constructor(string_value));
+                        value.clear();
+                        value.push('"');
+                    }
+                    Mode::EscapedString => {
+                        value.push('"');
+                        mode = Mode::String;
+                    }
+                    Mode::SlComment => {
+                        value.push('"');
+                    }
+                    _ => {
+                        return Err(LexerError {
+                            line,
+                            col,
+                            error: LexerErrorType::UnexpectedToken('"'),
+                        })
+                    }
+                };
+            }
+            '{' => match mode {
+                m @ Mode::Name
+                | m @ Mode::Class
+                | m @ Mode::MlWhitespace
+                | m @ Mode::SlWhitespace => {
+                    let string_value = value.iter().collect();
+                    let constructor = m.token_constructor().map_err(position_map)?;
+                    tokens.push(constructor(string_value));
+                    value.clear();
+                    mode = Mode::SlWhitespace;
+                    tokens.push(Token::LBrace(String::from('{')));
+                }
+                Mode::EscapedString => {
+                    return Err(LexerError {
+                        line,
+                        col,
+                        error: LexerErrorType::UnexpectedToken('{'),
+                    })
+                }
+                Mode::String | Mode::SlComment => {
+                    value.push('{');
+                }
+            },
+            '}' => match mode {
+                m @ Mode::Name
+                | m @ Mode::Class
+                | m @ Mode::MlWhitespace
+                | m @ Mode::SlWhitespace => {
+                    let string_value = value.iter().collect();
+                    let constructor = m.token_constructor().map_err(position_map)?;
+                    tokens.push(constructor(string_value));
+                    value.clear();
+                    mode = Mode::SlWhitespace;
+                    tokens.push(Token::RBrace(String::from('}')));
+                }
+                Mode::String | Mode::SlComment => {
+                    value.push('}');
+                }
+                Mode::EscapedString => {
+                    return Err(LexerError {
+                        line,
+                        col,
+                        error: LexerErrorType::UnexpectedToken('}'),
+                    })
+                }
+            },
+            c @ ' ' | c @ '\r' => {
+                match mode {
+                    m @ Mode::Name | m @ Mode::Class => {
+                        let string_value = value.iter().collect();
+                        let constructor = m.token_constructor().map_err(position_map)?;
+                        tokens.push(constructor(string_value));
+                        value.clear();
+                        mode = Mode::SlWhitespace;
+                    }
+                    Mode::String | Mode::SlComment | Mode::MlWhitespace | Mode::SlWhitespace => {}
+                    Mode::EscapedString => {
+                        return Err(LexerError {
+                            line,
+                            col,
+                            error: LexerErrorType::UnexpectedToken(c),
+                        })
+                    }
+                };
+                value.push(c);
+            }
+            c @ '\n' => {
+                match mode {
+                    m @ Mode::Name | m @ Mode::Class | m @ Mode::SlComment => {
+                        let string_value = value.iter().collect();
+                        let constructor = m.token_constructor().map_err(position_map)?;
+                        tokens.push(constructor(string_value));
+                        value.clear();
+                        mode = Mode::MlWhitespace;
+                    }
+                    Mode::MlWhitespace | Mode::SlWhitespace => {
+                        mode = Mode::MlWhitespace;
+                    }
+                    Mode::String => {}
+                    Mode::EscapedString => {
+                        return Err(LexerError {
+                            line,
+                            col,
+                            error: LexerErrorType::UnexpectedToken('\n'),
+                        })
+                    }
+                };
+                value.push(c);
+                line += 1;
+                col = -1;
+            }
+            '/' => {
+                match mode {
+                    Mode::String | Mode::SlComment => {}
+                    m @ Mode::Name
+                    | m @ Mode::Class
+                    | m @ Mode::SlWhitespace
+                    | m @ Mode::MlWhitespace => {
+                        let string_value = value.iter().collect();
+                        let constructor = m.token_constructor().map_err(position_map)?;
+                        tokens.push(constructor(string_value));
+                        value.clear();
+                        mode = Mode::SlComment;
+                    }
+                    Mode::EscapedString => {
+                        return Err(LexerError {
+                            line,
+                            col,
+                            error: LexerErrorType::UnexpectedToken('/'),
+                        })
+                    }
+                };
+                value.push('/');
+            }
+            v @ 'A'..='Z' | v @ 'a'..='z' | v @ '0'..='9' => {
+                match mode {
+                    Mode::String | Mode::SlComment | Mode::Name | Mode::Class => {}
+                    m @ Mode::SlWhitespace | m @ Mode::MlWhitespace => {
+                        let string_value = value.iter().collect();
+                        let constructor = m.token_constructor().map_err(position_map)?;
+                        tokens.push(constructor(string_value));
+                        value.clear();
+                        mode = Mode::Name;
+                    }
+
+                    Mode::EscapedString => {
+                        return Err(LexerError {
+                            line,
+                            col,
+                            error: LexerErrorType::UnexpectedToken(v),
+                        })
+                    }
+                };
+                value.push(v);
+            }
+            unrecognized_char => {
+                return Err(LexerError {
+                    line,
+                    col,
+                    error: LexerErrorType::UnexpectedToken(unrecognized_char),
+                })
+            }
+        }
+        col += 1;
+    }
+
+    Ok(tokens)
 }