99 lines
2.6 KiB
Rust
99 lines
2.6 KiB
Rust
use crate::tokens::Token;
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/* --------- *
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* AST nodes *
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* --------- */
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/// The AST node for the program
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#[derive(Default, Debug, Clone)]
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pub struct ProgramNode(pub Vec<StmtNode>);
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/// An AST node that represents a statement.
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#[derive(Debug, Clone)]
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pub enum StmtNode {
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/// A variable declaration
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VarDecl(String, Option<ExprNode>),
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/// An single expression
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Expression(ExprNode),
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/// The print statement
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Print(ExprNode),
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}
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/// An AST node that represents an expression.
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#[derive(Debug, Clone)]
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pub enum ExprNode {
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/// Binary expression.
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Binary {
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left: Box<ExprNode>,
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operator: Token,
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right: Box<ExprNode>,
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},
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/// Unary expression.
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Unary {
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operator: Token,
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right: Box<ExprNode>,
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},
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/// Grouping expression, containing a sub-expression.
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Grouping { expression: Box<ExprNode> },
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/// A litteral value, represented by the corresponding token.
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Litteral { value: Token },
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/// A reference to a variable.
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Variable { name: Token },
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}
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/* -------------------------------- *
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* Dumper trait and implementations *
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* -------------------------------- */
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/// This trait should be implemented by nodes to allow AST dumps.
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pub trait AstDumper {
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/// Dump the node as a string.
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fn dump(&self) -> String;
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}
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impl AstDumper for ProgramNode {
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fn dump(&self) -> String {
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self.0
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.iter()
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.map(|node| node.dump())
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.collect::<Vec<String>>()
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.join(" ")
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}
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}
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impl AstDumper for StmtNode {
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fn dump(&self) -> String {
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match self {
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Self::VarDecl(name, Some(expr)) => format!("( var {} {} )", name, expr.dump()),
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Self::VarDecl(name, None) => format!("( var {} nil )", name),
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Self::Expression(expr) => format!("( {} )", expr.dump()),
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Self::Print(expr) => format!("(print {})", expr.dump()),
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}
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}
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}
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impl AstDumper for ExprNode {
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fn dump(&self) -> String {
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match self {
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Self::Binary {
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left,
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operator,
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right,
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} => format!("( {} {} {} )", operator.lexeme, left.dump(), right.dump()),
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Self::Unary { operator, right } => format!("( {} {} )", operator.lexeme, right.dump()),
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Self::Grouping { expression } => format!("( {} )", expression.dump()),
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Self::Variable { name } => name.lexeme.clone(),
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Self::Litteral { value } => {
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if value.is_litteral() {
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value.lexeme.clone()
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} else {
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panic!("Unexpected token type for token {:#?}", value)
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}
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}
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}
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}
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}
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