More formatting and clippy fixes

inputs/printing_program.bas

@@ -0,0 +1,8 @@
+10 REM Assign vars
+20 LET a$="Hello"
+30 LET b$="World"
+40 LET c$=a$
+50 REM Print values
+60 PRINT a$
+70 PRINT b$
+80 PRINT c$

inputs/simple_program.bas

@@ -0,0 +1,4 @@
+10 PRINT "Hello World"
+20 LET apple=10
+30 LET b$="Hello"
+40 LET cat=apple

src/basic.rs

@@ -1,41 +1,173 @@
+use std::collections::HashMap;
+
 use nom::{
-    branch::alt,
-    bytes::complete::{escaped_transform, tag, take_until},
-    character::{
-        complete::{u32 as ccu32},
-        streaming::none_of,
-    },
-    combinator::{map, value},
-    sequence::{delimited, terminated, tuple},
-    IResult,
+    branch::alt, bytes::complete::tag, character::complete::u64 as ccu64, combinator::map,
+    multi::separated_list0, sequence::terminated, IResult,
 };
 
-pub type Line = (u32, Command);
+use crate::parsers::{generic, variables};
 
-#[derive(Debug, PartialEq, Eq)]
+pub type Line = (usize, Command);
+
+#[derive(Debug, PartialEq, Eq, Clone)]
 pub enum Command {
-    Print(String),
+    Print(PrintOutput),
+    GoTo(usize),
+    Var((String, Primitive)),
+    Comment,
     None,
 }
 
-fn read_string(i: &str) -> IResult<&str, String> {
-    // take_until("\"")(i)
-    delimited(
-        tag("\""),
-        escaped_transform(
-            none_of("\\\""),
-            '\\',
-            alt((value("\\", tag("\\")), value("\"", tag("\"")))),
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum Primitive {
+    Int(i64),
+    String(String),
+    Assignment(String),
+}
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum PrintOutput {
+    Value(String),
+    Variable(String),
+}
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum Node {
+    None,
+    Link { item: Line, next: Box<Node> },
+}
+
+impl Node {
+    fn push(&mut self, val: Line) {
+        *self = match self {
+            Self::Link { item, next } => {
+                next.push(val);
+                Self::Link {
+                    item: item.clone(),
+                    next: next.clone(),
+                }
+            }
+            Self::None => Self::Link {
+                item: val,
+                next: Box::new(Self::None),
+            },
+        }
+    }
+
+    pub fn find_line(&self, line: usize) -> Option<Node> {
+        if let Self::Link { item, next } = self {
+            if item.0 == line {
+                Some(self.clone())
+            } else {
+                next.find_line(line)
+            }
+        } else {
+            None
+        }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub struct Program {
+    nodes: Node,
+    current: Node,
+    vars: HashMap<String, Primitive>,
+}
+
+impl Program {
+    pub fn new(node: Node) -> Self {
+        Program {
+            vars: HashMap::new(),
+            nodes: node.clone(),
+            current: node,
+        }
+    }
+
+    pub fn jump_to_line(&mut self, line: usize) {
+        if let Some(node) = self.nodes.find_line(line) {
+            self.current = node;
+        } else {
+            panic!("Cannot jump to line {}, it does not exist", line);
+        }
+    }
+
+    pub fn execute(&mut self) {
+        let mut iter = self.clone();
+
+        while let Some(node) = iter.next() {
+            if let Node::Link { item, next: _ } = node {
+                match item.1 {
+                    Command::Print(PrintOutput::Value(line)) => println!("{}", line),
+                    Command::Print(PrintOutput::Variable(variable)) => {
+                        println!("{:?}", self.vars.get(&variable).unwrap())
+                    }
+                    Command::GoTo(line) => iter.jump_to_line(line),
+                    Command::Var((id, Primitive::Assignment(variable))) => {
+                        self.vars
+                            .insert(id, self.vars.get(&variable).unwrap().clone());
+                    }
+                    Command::Var((id, var)) => {
+                        self.vars.insert(id, var);
+                    }
+                    Command::Comment => (),
+                    _ => panic!("Unrecognised command"),
+                }
+            };
+        }
+    }
+}
+
+impl From<&str> for Program {
+    fn from(value: &str) -> Self {
+        let (_, program) = read_program(value).unwrap();
+        program
+    }
+}
+
+impl Iterator for Program {
+    type Item = Node;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let curr = self.current.clone();
+        match &self.current {
+            Node::Link { item: _, next } => {
+                self.current = *next.clone();
+                Some(curr)
+            }
+            Node::None => None,
+        }
+    }
+}
+
+fn match_command(i: &str) -> IResult<&str, &str> {
+    alt((tag("PRINT"), tag("GO TO"), tag("LET"), tag("REM")))(i)
+}
+
+fn parse_print_command(i: &str) -> IResult<&str, PrintOutput> {
+    alt((
+        map(
+            alt((
+                variables::parse_str_variable_name,
+                variables::parse_int_variable_name,
+            )),
+            PrintOutput::Variable,
         ),
-        tag("\""),
-    )(i)
+        map(generic::read_string, PrintOutput::Value),
+    ))(i)
 }
 
 fn parse_command(i: &str) -> IResult<&str, Command> {
-    let (i, (command, _)) = tuple((take_until(" "), tag(" ")))(i)?;
+    let (i, command): (&str, &str) = match_command(i).unwrap_or((i, ""));
+    let (i, _) = tag(" ")(i)?;
 
     let (i, cmd) = match command {
-        "PRINT" => map(read_string, Command::Print)(i)?,
+        "PRINT" => map(parse_print_command, Command::Print)(i)?,
+        "GO TO" => map(ccu64, |line| Command::GoTo(line as usize))(i)?,
+        "LET" => map(variables::parse_var, Command::Var)(i)?,
+        "REM" => {
+            let (i, _) = generic::consume_line(i)?;
+            (i, Command::Comment)
+        }
         _ => (i, Command::None),
     };
 
@@ -43,35 +175,222 @@ fn parse_command(i: &str) -> IResult<&str, Command> {
 }
 
 pub fn parse_line(line: &str) -> IResult<&str, Line> {
-    let (i, line_number) = terminated(ccu32, tag(" "))(line)?;
+    let (i, line_number) = map(terminated(ccu64, tag(" ")), |l| l as usize)(line)?;
     let (i, command) = parse_command(i)?;
     Ok((i, (line_number, command)))
 }
 
+pub fn read_program(i: &str) -> IResult<&str, Program> {
+    let (i, lines) = separated_list0(tag("\n"), parse_line)(i)?;
+    let mut node = Node::None;
+
+    for line in lines.iter() {
+        node.push(line.clone());
+    }
+
+    Ok((i, Program::new(node)))
+}
+
 #[cfg(test)]
 mod tests {
+    use crate::basic::PrintOutput;
+
+    use super::{parse_line, read_program, Command, Line, Node, Primitive};
+
+    use crate::parsers::generic::read_string;
+
     #[test]
     fn it_parses_a_print_command() {
         let input = "10 PRINT \"Hello, world\"";
-        let expected = (10, super::Command::Print(String::from("Hello, world")));
+        let expected = (
+            10,
+            Command::Print(PrintOutput::Value(String::from("Hello, world"))),
+        );
 
-        let (_, result) = super::parse_line(input).unwrap();
+        let (_, result) = parse_line(input).unwrap();
         assert_eq!(expected, result);
     }
 
     #[test]
     fn it_reads_a_string() {
         let input = r#""Hello, \"World\"""#;
-        let (_, output) = super::read_string(input).unwrap();
+        let (_, output) = read_string(input).unwrap();
         assert_eq!(r#"Hello, "World""#, output);
     }
 
     #[test]
     fn it_parses_a_print_command_with_escaped_quotes() {
         let input = r#"10 PRINT "Hello, \"world\"""#;
-        let expected = (10, super::Command::Print(String::from(r#"Hello, "world""#)));
+        let expected = (
+            10,
+            Command::Print(PrintOutput::Value(String::from(r#"Hello, "world""#))),
+        );
 
-        let (_, result) = super::parse_line(input).unwrap();
+        let (_, result) = parse_line(input).unwrap();
         assert_eq!(expected, result);
     }
+
+    #[test]
+    fn it_parses_a_goto_command() {
+        let input = "20 GO TO 10";
+        let expected = (20, Command::GoTo(10));
+        let (_, result) = parse_line(input).unwrap();
+        assert_eq!(expected, result);
+    }
+
+    #[test]
+    fn it_can_create_a_linked_list_for_a_program() {
+        let mut node = Node::Link {
+            item: (
+                10,
+                Command::Print(PrintOutput::Value(String::from("Hello world"))),
+            ),
+            next: Box::new(Node::None),
+        };
+        node.push((20, Command::GoTo(10)));
+
+        let expected = Node::Link {
+            item: (
+                10,
+                Command::Print(PrintOutput::Value(String::from("Hello world"))),
+            ),
+            next: Box::new(Node::Link {
+                item: (20, Command::GoTo(10)),
+                next: Box::new(Node::None),
+            }),
+        };
+        assert_eq!(node, expected);
+    }
+
+    #[test]
+    fn it_finds_a_node_by_line_number() {
+        let mut node = Node::Link {
+            item: (
+                10,
+                Command::Print(PrintOutput::Value(String::from("Hello world"))),
+            ),
+            next: Box::new(Node::None),
+        };
+        node.push((
+            20,
+            Command::Print(PrintOutput::Value(String::from("I'm a second line"))),
+        ));
+        node.push((
+            30,
+            Command::Print(PrintOutput::Value(String::from("Still printing..."))),
+        ));
+        node.push((40, Command::GoTo(10)));
+
+        let expected: Option<Node> = Some(Node::Link {
+            item: (
+                30,
+                Command::Print(PrintOutput::Value(String::from("Still printing..."))),
+            ),
+            next: Box::new(Node::Link {
+                item: (40, Command::GoTo(10)),
+                next: Box::new(Node::None),
+            }),
+        });
+        let result = node.find_line(30);
+        assert_eq!(expected, result);
+    }
+
+    #[test]
+    fn it_reads_a_program() {
+        let lines = "10 PRINT \"Hello world\"\n20 GO TO 10";
+        let expected_node = Node::Link {
+            item: (
+                10,
+                Command::Print(PrintOutput::Value(String::from("Hello world"))),
+            ),
+            next: Box::new(Node::Link {
+                item: (20, Command::GoTo(10)),
+                next: Box::new(Node::None),
+            }),
+        };
+        let expected = ("", super::Program::new(expected_node));
+        let result = read_program(lines).unwrap();
+        assert_eq!(expected, result);
+    }
+
+    #[test]
+    fn it_parses_an_integer() {
+        let line = "10 LET a=22";
+        let expected: Line = (10, Command::Var((String::from("a"), Primitive::Int(22))));
+        let (_, result) = parse_line(line).unwrap();
+        assert_eq!(expected, result);
+    }
+
+    #[test]
+    fn it_parses_a_many_char_integer() {
+        let line = "10 LET apple=1";
+        let expected: Line = (10, Command::Var((String::from("apple"), Primitive::Int(1))));
+        let (_, result) = parse_line(line).unwrap();
+        assert_eq!(expected, result);
+    }
+
+    #[test]
+    fn it_fails_if_integer_var_name_starts_with_number() {
+        let line = "10 LET 0apple=1";
+        let result = parse_line(line);
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn it_parses_a_string_variable() {
+        let line = r#"10 LET a$="Hello world""#;
+        let expected: Line = (
+            10,
+            Command::Var((
+                String::from("a$"),
+                Primitive::String(String::from("Hello world")),
+            )),
+        );
+        let (_, result) = parse_line(line).unwrap();
+        assert_eq!(expected, result);
+    }
+
+    #[test]
+    fn it_fails_a_string_var_with_a_multichar_name() {
+        let line = r#"10 LET asd$="Hello world""#;
+        let result = parse_line(line);
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn it_fails_a_string_var_with_a_numeric_name() {
+        let line = r#"10 LET 0$="Hello world""#;
+        let result = parse_line(line);
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn it_assigns_one_variable_to_another() {
+        let line = "10 LET a=b$";
+        let (_, result) = parse_line(line).unwrap();
+        let expected: Line = (
+            10,
+            Command::Var((String::from("a"), Primitive::Assignment(String::from("b$")))),
+        );
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn it_parses_a_print_command_with_a_variable_name() {
+        let line = "10 PRINT a$";
+        let (_, result) = parse_line(line).unwrap();
+        let expected: Line = (
+            10,
+            Command::Print(PrintOutput::Variable(String::from("a$"))),
+        );
+        assert_eq!(result, expected);
+    }
+
+    #[test]
+    fn it_parses_a_comment() {
+        let line = "10 REM This is an arbitrary comment";
+        let (_, result) = parse_line(line).unwrap();
+        let expected: Line = (10, Command::Comment);
+        assert_eq!(result, expected);
+    }
 }

src/main.rs

@@ -1,17 +1,10 @@
 use std::fs;
 
 mod basic;
+mod parsers;
 
 fn main() {
-    let file = fs::read_to_string("./inputs/hello_world.bas").unwrap();
-    let lines = file.lines().next().unwrap();
-    let (_, (_, command)) = basic::parse_line(lines).unwrap();
-    match command {
-        basic::Command::Print(input) => {
-            println!("{}", input);
-        }
-        _ => {
-            panic!("Command not recognised");
-        }
-    };
+    let file = fs::read_to_string("./inputs/printing_program.bas").unwrap();
+    let mut program = basic::Program::from(file.as_str());
+    program.execute();
 }

src/parsers.rs

@@ -0,0 +1,2 @@
+pub mod generic;
+pub mod variables;

src/parsers/generic.rs

@@ -0,0 +1,25 @@
+use nom::{
+    branch::alt,
+    bytes::complete::{escaped_transform, tag, take_while},
+    character::complete::none_of,
+    combinator::value,
+    sequence::delimited,
+    IResult,
+};
+
+// Take everything until it hits a newline, if it does
+pub fn consume_line(i: &str) -> IResult<&str, &str> {
+    take_while(|c| c != '\n')(i)
+}
+
+pub fn read_string(i: &str) -> IResult<&str, String> {
+    delimited(
+        tag("\""),
+        escaped_transform(
+            none_of("\\\""),
+            '\\',
+            alt((value("\\", tag("\\")), value("\"", tag("\"")))),
+        ),
+        tag("\""),
+    )(i)
+}

src/parsers/variables.rs

@@ -0,0 +1,51 @@
+use nom::{
+    branch::alt,
+    bytes::complete::tag,
+    character::complete::{alphanumeric1, anychar, digit1, i64 as cci64},
+    combinator::{map, not, verify},
+    sequence::{preceded, terminated},
+    IResult,
+};
+
+use crate::basic::Primitive;
+
+use super::generic::{consume_line, read_string};
+
+pub fn parse_int_variable_name(i: &str) -> IResult<&str, String> {
+    map(preceded(not(digit1), alphanumeric1), String::from)(i)
+}
+
+pub fn parse_int(i: &str) -> IResult<&str, (String, Primitive)> {
+    let (i, id) = parse_int_variable_name(i)?;
+    let (i, _) = tag("=")(i)?;
+    let (i, var) = map(cci64, Primitive::Int)(i)?;
+
+    Ok((i, (id, var)))
+}
+
+pub fn parse_str_variable_name(i: &str) -> IResult<&str, String> {
+    let (i, id) = terminated(verify(anychar, |c| c.is_alphabetic()), tag("$"))(i)?;
+    let id = format!("{}$", id);
+    Ok((i, id))
+}
+
+pub fn parse_str(i: &str) -> IResult<&str, (String, Primitive)> {
+    let (i, id) = parse_str_variable_name(i)?;
+    let (i, _) = tag("=")(i)?;
+    let (i, var) = map(read_string, Primitive::String)(i)?;
+    Ok((i, (id, var)))
+}
+
+pub fn parse_assignment(i: &str) -> IResult<&str, (String, Primitive)> {
+    let (i, id) = alt((parse_str_variable_name, parse_int_variable_name))(i)?;
+    let (i, _) = tag("=")(i)?;
+    let (i, assigned_variable) = consume_line(i)?;
+    Ok((
+        i,
+        (id, Primitive::Assignment(assigned_variable.to_string())),
+    ))
+}
+
+pub fn parse_var(i: &str) -> IResult<&str, (String, Primitive)> {
+    alt((parse_int, parse_str, parse_assignment))(i)
+}