Implement define statements

demo/Cargo.lock

@@ -1739,9 +1739,9 @@ dependencies = [
 
 [[package]]
 name = "regex"
-version = "1.8.1"
+version = "1.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "af83e617f331cc6ae2da5443c602dfa5af81e517212d9d611a5b3ba1777b5370"
+checksum = "81ca098a9821bd52d6b24fd8b10bd081f47d39c22778cafaa75a2857a62c6390"
 dependencies = [
  "aho-corasick",
  "memchr",
@@ -1750,9 +1750,9 @@ dependencies = [
 
 [[package]]
 name = "regex-syntax"
-version = "0.7.1"
+version = "0.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a5996294f19bd3aae0453a862ad728f60e6600695733dd5df01da90c54363a3c"
+checksum = "436b050e76ed2903236f032a59761c1eb99e1b0aead2c257922771dab1fc8c78"
 
 [[package]]
 name = "renrs"
@@ -1760,6 +1760,7 @@ version = "0.1.0"
 dependencies = [
  "pest",
  "pest_derive",
+ "regex",
 ]
 
 [[package]]

demo/demo.rpy

@@ -1,5 +1,6 @@
 # Control testing
-"Bob" "I will not say anything"
+"Bob" "I will not say anything, [foo]"
+define foo = "bar"
 if False:
     "Bob" "W-what? Why am I saying this?"
     if True:
@@ -11,4 +12,6 @@ if True:
     "Bob" "...cereal!"
     if False:
         "Bob" "But I actually hate it."
+        define bar = "potato"
+        define foo = bar
 "Bob sat on the bench."

renrs/Cargo.toml

@@ -9,3 +9,4 @@ edition = "2021"
 [dependencies]
 pest = "2.6.0"
 pest_derive = "2.6.0"
+regex = "1.8.3"

renrs/src/lib.rs

@@ -1,8 +1,9 @@
 use core::panic;
-use std::{fs, path::PathBuf};
+use std::{fs, path::PathBuf, collections::HashMap, rc::Rc, cell::RefCell, hash::Hash};
 
 use pest::Parser;
 use pest_derive::Parser;
+use regex::Regex;
 
 #[derive(Parser)]
 #[grammar = "rpy.pest"]
@@ -31,16 +32,41 @@ impl Token {
     }
 }
 
+impl ToString for Token {
+    fn to_string(&self) -> String {
+        use Token::*;
+        match self {
+            Keyword(_) => panic!("keywords should not be used as values"),
+            Str(string) => string.to_owned(),
+            Array(array) => format!(
+                "[{}]",
+                array
+                    .iter()
+                    .map(|token| token.to_string())
+                    .collect::<Vec<String>>()
+                    .join(", ")
+            ),
+            Boolean(boolean) => match boolean {
+                true => "True",
+                false => "False",
+            }.to_owned(),
+            Number(number) => number.to_string(),
+        }
+    }
+}
+
 // Indented command block
 #[derive(Debug)]
 struct CommandBlock {
+    parent: Option<Rc<RefCell<CommandBlock>>>,
     control: Option<Control>,
     elements: Vec<BlockElement>,
     next: Option<usize>,
+    variables: Option<Rc<RefCell<HashMap<String, Token>>>>,
 }
 
 impl CommandBlock {
-    fn next(&mut self) -> Option<&Command> {
+    fn next(&mut self) -> Option<Command> {
         let mut next = match self.next {
             Some(next) => next,
             None => return None,
@@ -53,14 +79,14 @@ impl CommandBlock {
         for element in &mut self.elements[next..] {
             match element {
                 BlockElement::Command(command) => {
-                    result = Some(&*command);
+                    result = Some(command.clone());
                     next += 1;
                     break;
                 },
                 BlockElement::Block(block) => {
-                    match block.next() {
+                    match block.borrow_mut().next() {
                         Some(command) => {
-                            result = Some(command);
+                            result = Some(command.clone());
                             break;
                         },
                         None => {
@@ -84,14 +110,32 @@ impl CommandBlock {
             If { condition } => *condition,
         })
     }
+
+    fn get_variables(&self) -> HashMap<String, Token> {
+        match &self.variables {
+            Some(variables) => {
+                let variables = variables.borrow().clone();
+                if let Some(parent) = &self.parent {
+                    let mut parent_variables = parent.borrow().get_variables();
+                    parent_variables.extend(variables.into_iter());
+                    parent_variables
+                } else {
+                    variables
+                }
+            },
+            None => HashMap::new(),
+        }
+    }
 }
 
 impl Default for CommandBlock {
     fn default() -> Self {
         Self {
+            parent: None,
             control: None,
             elements: Vec::new(),
             next: Some(0),
+            variables: None,
         }
     }
 }
@@ -99,32 +143,43 @@ impl Default for CommandBlock {
 #[derive(Debug)]
 enum BlockElement {
     Command(Command),
-    Block(CommandBlock),
+    Block(Rc<RefCell<CommandBlock>>),
 }
 
-type Script = CommandBlock;
-
 #[derive(Debug)]
 #[allow(dead_code)]
 enum Control {
     If { condition: bool },
 }
 
+impl Control {
+    fn has_variable_scope(&self) -> bool {
+        match self {
+            _ => false,
+        }
+    }
+}
+
 // Parsed script commands
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 #[allow(dead_code)]
 enum Command {
     Say { name: Option<String>, text: String },
     Eat { food: String, politely: bool },
+    Define { variable: String, value: Token },
 }
 
 impl Command {
-    fn is_blocking(&self) -> bool {
+    fn execute(&self, context: &Rc<RefCell<CommandBlock>>) -> Option<Event> {
         use Command::*;
-        match self {
-            Say { .. } => true,
-            _ => false,
-        }
+        Some(match self {
+            Say { name, text } => Event::Say {
+                name: name.clone(),
+                text: text.clone(),
+            },
+            Define { .. } => panic!("define command should not be executed at runtime!"),
+            Eat { .. } => return None,
+        }.process(context))
     }
 }
 
@@ -133,6 +188,42 @@ pub enum Event {
     Say { name: Option<String>, text: String },
 }
 
+impl Event {
+    fn is_blocking(&self) -> bool {
+        use Event::*;
+        match self {
+            Say { .. } => true,
+        }
+    }
+
+    fn process(mut self, context: &Rc<RefCell<CommandBlock>>) -> Self {
+        use Event::*;
+        match &mut self {
+            Say { name, text } => {
+                let context = context.borrow();
+                let variables = context.get_variables();
+                *name = name.as_deref().map(|name| interpolate_string(&name, &variables));
+                *text = interpolate_string(&text, &variables);
+            }
+        }
+        self
+    }
+}
+
+fn interpolate_string(input: &str, variables: &HashMap<String, Token>) -> String {
+    let re = Regex::new(r"\[(\w+)\]").unwrap();
+    let interpolated_string = re.replace_all(input, |caps: &regex::Captures| {
+        let var_name = &caps[1];
+        if let Some(value) = variables.get(var_name) {
+            value.to_string()
+        } else {
+            format!("[{}]", var_name)
+        }
+    });
+
+    interpolated_string.into_owned()
+}
+
 // ======
 // Parser
 // ======
@@ -140,25 +231,33 @@ pub enum Event {
 type Pair<'a> = pest::iterators::Pair<'a, Rule>;
 
 // Read file into commands
-fn parse_file(file_path: &PathBuf) -> CommandBlock {
+fn parse_file(file_path: &PathBuf) -> Rc<RefCell<CommandBlock>> {
     let unparsed_file = fs::read_to_string(file_path).expect("cannot find file");
     parse(&unparsed_file)
 }
 
-fn parse(script: &str) -> CommandBlock {
+fn parse(script: &str) -> Rc<RefCell<CommandBlock>> {
     let file = RpyParser::parse(Rule::File, script)
         .expect("unsuccessful parse")
         .next()
         .unwrap();
-    parse_block(file)
+    parse_block(file, None)
 }
 
-fn parse_block(block: Pair) -> CommandBlock {
-    CommandBlock {
-        elements: {
+fn parse_block(pair: Pair, definitions: Option<Rc<RefCell<HashMap<String, Token>>>>) -> Rc<RefCell<CommandBlock>> {
+    //let variables: HashMap<String, Token> = HashMap::new();
+    let is_root = definitions.is_none();
+    let definitions = definitions.unwrap_or(Rc::new(RefCell::new(HashMap::new())));
+    let block_rc = Rc::new(RefCell::new(CommandBlock {
+        variables: if is_root { Some(definitions.clone()) } else { None },
+        ..Default::default()
+    }));
+    {
+        let mut block = block_rc.borrow_mut();
+        block.elements = {
             let mut control = None;
             let mut elements = Vec::new();
-            for pair in block.into_inner() {
+            for pair in pair.into_inner() {
                 elements.push(match pair.as_rule() {
                     Rule::Control => {
                         if control.is_some() {
@@ -167,25 +266,50 @@ fn parse_block(block: Pair) -> CommandBlock {
                         control = Some(parse_control(pair));
                         continue;
                     },
-                    Rule::Line => BlockElement::Command(parse_command(pair)),
+                    Rule::Line => BlockElement::Command(match parse_command(pair) {
+                        Command::Define { variable, value } => {
+                            let mut value = value;
+                            if let Token::Keyword(keyword) = value {
+                                value = definitions
+                                    .borrow()
+                                    .get(&keyword)
+                                    .unwrap_or_else(|| panic!("undefined variable `{keyword}`"))
+                                    .clone();
+                            }
+                            definitions.borrow_mut().insert(variable, value);
+                            continue;
+                        }
+                        command => command,
+                    }),
                     Rule::Block => BlockElement::Block({
-                        let mut block = parse_block(pair);
-                        if control.is_none() {
+                        let subblock_rc = parse_block(pair, Some(definitions.clone()));
+                        {
+                            let mut subblock = subblock_rc.borrow_mut();
+                            if let Some(control) = control.as_ref() {
+                                if control.has_variable_scope() {
+                                    subblock.variables = Some(Rc::new(RefCell::new(HashMap::new())));
+                                }
+                            } else {
                                 panic!("block should have control");
                             }
-                        block.control = control;
+                            subblock.parent = Some(block_rc.clone());
+                            subblock.control = control;
                             control = None;
-                        block
+                        }
+                        subblock_rc
                     }),
                     Rule::EOI => break, // end
                     _ => unreachable!(),
                 });
             }
             elements
-        },
-        ..Default::default()
+        };
+        if is_root {
+            block.variables = Some(definitions);
         }
     }
+    block_rc
+}
 
 fn parse_line(pair: Pair) -> Vec<Token> {
     pair
@@ -229,6 +353,10 @@ fn parse_command(pair: Pair) -> Command {
             name: Some(name.to_owned()),
             text: text.to_owned(),
         },
+        [Keyword(keyword), Keyword(variable), Keyword(equals), value] if keyword.eq("define") && equals.eq("=") => Define {
+            variable: variable.to_owned(),
+            value: value.clone(),
+        },
         [Keyword(keyword), Str(food), tail @ ..] if keyword.eq("eat") => Eat {
             food: food.to_owned(),
             politely: match tail {
@@ -293,7 +421,7 @@ fn parse_token(pair: Pair) -> Token {
 // =====
 
 pub struct State {
-    script: Script,
+    script: Rc<RefCell<CommandBlock>>,
 }
 
 impl State {
@@ -305,20 +433,15 @@ impl State {
 
     pub fn next(&mut self) -> Option<Event> {
         while let Some(command) = self.next_command() {
-            if command.is_blocking() {
-                return Some(match command {
-                    Command::Say { name, text } => Event::Say {
-                        name: name.clone(),
-                        text: text.clone()
-                    },
-                    _ => unimplemented!(),
-                });
+            let event = command.execute(&self.script);
+            if event.as_ref().map_or(false, |event| event.is_blocking()) {
+                return event;
             }
         }
         None
     }
 
-    fn next_command(&mut self) -> Option<&Command> {
-        self.script.next()
+    fn next_command(&mut self) -> Option<Command> {
+        self.script.borrow_mut().next()
     }
 }

renrs/src/rpy.pest

@@ -43,7 +43,7 @@ Number = @{
 
 // comments are a # followed by
 // any Number of non-newline characters
-// TODO: Inline comments broken by no implicit whitespace
+// FIXME: Inline comments broken by no implicit whitespace
 COMMENT = _{ "#" ~ char* }
 
 Colon = { ":" }